Systems and methods for identifying one or more substances using micro-plasma induced breakdown spectroscopy

Abstract

A system for identifying one or more substances in a liquid sample using micro¬ plasma induced breakdown spectroscopy (MIBS) includes a system controller including a processor and memory encoded with instructions that, when executed by the processor, cause the processer to activate one or more pulse generators to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the voltage of each of the one or more electrical pulses applied to the plasma electrode is between 13 kilovolts (kV) and 40 kV, and activate an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by an optical collector.

Description

SYSTEMS AND METHODS FOR IDENTIFYING ONE OR MORE SUBSTANCES USING MICRO-PLASMA INDUCED BREAKDOWN SPECTROSCOPYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional patent application Serial No. 63 / 536,300 filed September 1 , 2023, and entitled "Methods and Systems for Identifying and Measuring Elements Using Micro-Plasma Induced Breakdown Spectroscopy," which is hereby incorporated herein by reference in its entirety for all purposes.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.BACKGROUND

[0003] Optical emission spectroscopy (OES) is a technique used to detect or identify (as well as potentially quantify) the presence of one or more substances in various sample materials. Particularly, OES exploits the characteristic emission spectra of different substances such as chemical elements to identify and quantify the presence of said substances within a sample material. Particularly, when a sample material is exposed to a high-energy excitation source, such as a plasma, flame, or electrical arc / spark, its atoms become excited to higher energy levels. Additionally, as these excited atoms return to their ground state, they emit light at specific wavelengths corresponding to the energy difference between their respective excited and ground states. By analyzing the emitted light, the elemental composition of the sample material can be determined.BRIEF SUMMARY OF THE DISCLOSURE

[0004] An embodiment of a system for identifying one or more substances in a liquid sample using micro-plasma induced breakdown spectroscopy (MIBS) comprises a voltage source, one or more pulse generators electrically connected to the voltage source, a plasma receptacle configured to receive a liquid sample, a plasma electrode electrically connected to the one or more pulse generators and having an exposed electrode tip positioned at least partially in the plasma receptacle, an optical detector comprising an optical collector positioned at least partially in the plasma receptacle, and one or more spectrometers in optical communication with the optical collector, and a system controller comprising a processor and memory encoded with instructions that, when executed by the processor, cause the processer to activate the one or more pulsegenerators to apply one or more electrical pulses to the plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the voltage of each of the one or more electrical pulses applied to the plasma electrode is between 13 kilovolts (kV) and 40 kV, and activate the optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector. In some embodiments, the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz. In some embodiments, the MIBS system comprises only one of the one or more pulse generators, the one of the one or more pulse generators comprising a single spark gap. In certain embodiments, a maximum radius of the exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm. In certain embodiments, an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW. In some embodiments, an electric field at the exposed electrode tip of the plasma electrode, in response to the activation of the pulse generator, is between 0.15 gigavolts / meter (GV / m) and 1.2 GV / m. In some embodiments, the plasma receptacle comprises a fluid conduit extending between an upstream end configured to receive a continuous flow of the liquid sample, and an opposing discharge end configured to discharge the continuous flow of the liquid sample. In certain embodiments, the plasma receptacle comprises plasma chamber configured to receive a batch of the liquid sample. In certain embodiments, the system comprises an outer case, and one or more racks receivable in the outer case internally housing at least one of the pulse generator, the plasma receptacle, and the optical detector. In some embodiments, the one or more racks internally house each of the pulse generator, the plasma receptacle, and the optical detector. In some embodiments, the one or more substances comprise one or more chemical compounds.

[0005] An embodiment of a system for identifying one or more substances in a liquid sample using MIBS comprises a voltage source, a pulse generator electrically connected to the voltage source, a plasma receptacle configured to receive a liquid sample, a plasma electrode electrically connected to the pulse generator and having an electrode tip positioned at least partially in the plasma receptacle, an optical detector comprising an optical collector positioned at least partially in the plasma receptacle, and one or more spectrometers in optical communication with the optical collector, and a system controller comprising a processor and memory encoded with instructions that,when executed by the processor, cause the processer to activate the pulse generator to apply one or more electrical pulses to the plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the energy per pulse for each of the one or more electrical pulses is between 20 millijoules (mJ) and 300 mJ, and activate the optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector. In certain embodiments, the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz. In certain embodiments, the pulse generator comprises a single spark gap. In some embodiments, a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm. In some embodiments, the one or more spectrometers comprise an optical disperser configured to produce a dispersed optical signal into its component wavelengths, and an optical sensor optically coupled to the optical disperser and configured to measure an intensity of the component wavelengths of the dispersed optical signal. In certain embodiments, the plasma receptacle comprises a fluid conduit extending between an upstream end configured to receive a continuous flow of the liquid sample, and an opposing discharge end configured to discharge the continuous flow of the liquid sample. In certain embodiments, the one or more substances comprise one or more chemical compounds.

[0006] An embodiment of a system for identifying one or more substances in a liquid sample using MIBS comprises a voltage source, a pulse generator electrically connected to the voltage source, a plasma receptacle configured to receive a liquid sample, a plasma electrode electrically connected to the pulse generator and having an electrode tip positioned at least partially in the plasma receptacle, an optical detector comprising an optical collector positioned at least partially in the plasma receptacle, and one or more spectrometers in optical communication with the optical collector, and a system controller comprising a processor and memory encoded with instructions that, when executed by the processor, cause the processer to activate the pulse generator to apply one or more electrical pulses to the plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the duration for each of the one or more electrical pulses is between 0.005 microseconds (ps) and 40 ps, and activate the optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector. In some embodiments, thefrequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz. In some embodiments, the pulse generator comprises a single spark gap. In certain embodiments, a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm. In certain embodiments, the plasma receptacle comprises a fluid conduit extending between an upstream end configured to receive a continuous flow of the liquid sample, and an opposing discharge end configured to discharge the continuous flow of the liquid sample. In some embodiments, the one or more substances comprise one or more chemical compounds.

[0007] An embodiment of a method for identifying one or more substances in a liquid sample using MIBS comprises (a) activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample, wherein the voltage of each of the one or more electrical pulses applied to the plasma electrode is between 13 kilovolts (kV) and 40 kV, and (b) activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical detector. In some embodiments, the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz. In certain embodiments, a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm. In certain embodiments, an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW. In some embodiments, the method comprises (c) flowing a continuous flow of the liquid sample through a fluid conduit in which the plasma electrode is at least partially received as the pulse generator is activated to apply the one or more electrical pulses to generate the plasma discharge in the liquid sample as it flows through the fluid conduit. In some embodiments, the one or more substances comprise one or more chemical compounds.

[0008] An embodiment of a method for identifying one or more substances in a liquid sample using MIBS comprises (a) activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample, wherein the energy per pulse for each of the one or more electrical pulses is between 20 millijoules (mJ) and 300 mJ, and (b) activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical detector. In some embodiments, the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.In some embodiments, a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm. In certain embodiments, an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW. In certain embodiments, the method comprises (c) flowing a continuous flow of the liquid sample through a fluid conduit in which the plasma electrode is at least partially received as the pulse generator is activated to apply the one or more electrical pulses to generate the plasma discharge in the liquid sample as it flows through the fluid conduit. In some embodiments, the one or more substances comprise one or more chemical compounds.

[0009] An embodiment of a method for identifying one or more substances in a liquid sample using MIBS comprises (a) activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample, wherein the duration for each of the one or more electrical pulses is between 0.005 microseconds (ps) and 40 ps, and (b) activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical detector. In some embodiments, the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz. In certain embodiments, a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm. In certain embodiments, an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW. In some embodiments, the method comprises (c) flowing a continuous flow of the liquid sample through a fluid conduit in which the plasma electrode is at least partially received as the pulse generator is activated to apply the one or more electrical pulses to generate the plasma discharge in the liquid sample as it flows through the fluid conduit. In some embodiments, the one or more substances comprise one or more chemical compounds.

[0010] Embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical characteristics of the disclosed embodiments in order that the detailed description that follows may be better understood. The various characteristics and features described above, as well as others, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated that the conception and the specificembodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the disclosed embodiments. It should also be realized that such equivalent constructions do not depart from the spirit and scope of the principles disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For a detailed description of exemplary embodiments of the disclosure, reference will now be made to the accompanying drawings in which:

[0012] FIGS. 1A and W are schematic views of embodiments of systems for identifying one or more substances using MIBS in accordance with principles described herein;

[0013] FIG. 2 is a perspective view of another embodiment of a system for identifying one or more substances using MIBS in accordance with principles described herein;

[0014] FIG. 3 is a schematic view of the MIBS system shown in FIG. 2;

[0015] FIG. 4 is a perspective view of an embodiment of a fluid system in accordance with principles described herein;

[0016] FIGS. 5 and 6 zoomed-in side views of embodiments of plasma electrodes in accordance with principles described herein;

[0017] FIG. 7 is a block diagram of another embodiment of a system for identifying one or more substances using MIBS in accordance with principles described herein;

[0018] FIG. 8 is a perspective view of another embodiment of a system for identifying one or more substances using MIBS in accordance with principles described herein;

[0019] FIG. 9 is a top view of an embodiment of a first rack of the MIBS system of FIG.8 in accordance with principles described herein;

[0020] FIG. 10 is a top view of an embodiment of a second rack of the MIBS system of FIG. 8 in accordance with principles described herein;

[0021] FIG. 11 is a graph of spectral lines produced by a MIBS system in accordance with principles described herein;

[0022] FIG. 12 is a block diagram of an embodiment of a computer system in accordance with principles described herein; and

[0023] FIG. 13 is a flowchart of an embodiment of a method for identifying one or more substances using MIBS in accordance with principles described herein.DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

[0024] The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.

[0025] Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

[0026] Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.

[0027] In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to...” Also, the term "couple" or "couples" is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms "axial" and "axially" generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms "radial" and "radially" generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis.

[0028] As described above, OES is a technique used to detect the presence of one or more substances in various sample materials by analyzing light emitted from the sample material in response to being exposed to a high-energy excitation source. OES is widely used in various industrial, environmental, and scientific applications due to its ability todetect and quantify different chemical elements of sample materials. For example, OES is utilized in environmental monitoring for detecting pollutants and toxic elements, metallurgical analysis for analyzing the composition of metals and alloys, in pharmaceuticals for ensuring the purity of selected drugs and other pharmaceutical products, and in the food industry for ensuring the safety and quality of food products.

[0029] OES may be implemented or practiced using a variety of different techniques employing varying excitation sources. For example, OES may be implemented using inductively-coupled plasma (ICP), direct-current plasma (DCP), microwave-induced plasma (MIP), and laser-induced breakdown (LIBS). Generally, several OES techniques such as ICP and DCP techniques are limited in their applicability by requirements related to preparing the sample material for excitation (e.g., dissolving of solid sample material in a liquid), maintaining the sample material in a predefined state or atmosphere during operation (e.g., maintaining the sample material under a vacuum), and other costly and time delaying requirements and complications.

[0030] LIBS addresses some of the limitations of conventional OES techniques by limiting the degree of required sample preparation and providing a solution that can be flexibly implemented outside of tightly controlled laboratory settings. However, while LIBS addresses some of the limitations of conventional OES techniques, it introduces shortcomings and limitations of its own.

[0031] Particularly, LIBS uses a high-energy laser pulse to ablate a sample material and thereby produce a laser induced plasma that is probed via a spectrometer and the like to estimate elemental compositions of the subject material. The laser pulse employed in LIBS can range from femtoseconds to nanoseconds. LIBS may be employed with both solid sample materials and liquid sample materials. As used herein, the term “liquid sample material” and “liquid sample” include single-phase liquids along with multi-phase or two-phase fluids. For instance, some liquid samples may include some entrained gas bubbles and the like which can be introduced into the liquid sample intentionally or unintentionally.

[0032] For LIBS employed on liquid samples, optical lenses are typically used to focus the laser pulse at a predefined location. Focusing of the laser pulse permits exceeding the breakdown threshold (breakdown threshold irradiance) of the liquid sample whereby plasma is generated in the liquid sample. Parameters materially affecting the performance of LIBS systems include, for example, laser energy, laser wavelength, and laser pulse duration. In a laser-induced plasma generated by a LIBS system, theinternal energy modes are typically in a state of local thermodynamic equilibrium (LTE) where the temperature of the plasma is approximately equal to each of the rotational, vibrational, and electron temperatures such that the laser-generated plasma is a thermal plasma having a relatively high electron density (e.g., 1023per centimeter cubed). LTE plasma discharges having relatively high electron densities, such as those produced by LIBS systems, generally sufferfrom reduced emission fidelity due to broadening or even splitting of the peaks of the emission spectra of the plasma discharge. Such limitations often necessitate the use of computationally expensive deconvolution techniques or supplementary diagnostic methods which may add significant time and expense to the process, limiting the applicability of LIBS systems.

[0033] Additionally, while LIBS systems can be used in conjunction with liquid samples, LIBS systems are generally less energy efficient when used in conjunction with liquid samples because a greater proportion of the energy of the laser is expended evaporating the liquid, and where the moving breakdown phenomenon associated with LIBS systems makes this process relatively more complex. Particularly, moving breakdown phenomenon, frequently observed in LIBS systems used in conjunction with liquid samples, corresponds to the condition in which the plasma discharge occurs away from the focal point such as at locations positioned towards the incoming laser beam in different sequential layers - each layer establishing its own plasma discharge.

[0034] Further, LIBS systems are affected by the presence of debris and changes in liquid opacity given that said systems generally rely on optical focusing techniques. Lasers typically used in LIBS systems include Class IV or Class 3B lasers that are not contained in an external housing (meaning users can come into physical contact with the laser beam) and often operate at a wavelength of 1064 nanometers- meaning the laser beam may be invisible to the human eye in some applications and thus can result in injury to a user’s eyes or skins due to inadvertent contact between the user and the invisible laser beam. For this reason, users of LIBS systems are typically required to maintain a predefined distance from the beam (e.g., Nominal Ocular Hazard Distance), wear appropriately rated safety goggles, never look directly into the beam, and to be cautious of any reflective surfaces while operating the laser. MIBS does not have such operation hazards, as everything is enclosed in a case.

[0035] Accordingly, embodiments of methods and systems described herein provides a portable, no special sample preparation, quick sample analysis, and inexpensive means for identifying and measuring substances in liquid samples in comparison toconventional systems. As used herein, the term “substance” and “substances” refers to both chemical elements (e.g., any element listed in the Periodic Table of elements) and chemical compounds including, for example, Oxygen-Hydrogen (OH) molecular bonds, Carbon-Fluorine (CF) molecular bonds, Carbon-Sulfur (CS) molecular bonds, Carbon- Hydrogen (CH) molecular bonds, Carbon-Carbon (C2) molecular bonds, Hydrogen- Hydrogen (H2) molecular bonds, Nitrogen-Oxygen (NO) molecular bonds, Nitrogen- Nitrogen (N2) molecular bonds, Oxygen-Oxygen (02) molecular bonds, among others. In this manner, embodiments of MIBS systems described herein may be used to identify presence of organic compounds, inorganic compounds, hydrocarbon compounds, gases, oils, bacterial presence, and the like. Atoms and diatomic molecules exhibit multiple spectral line transitions, each occurring at different wavelengths and can be used to determine the presence or absence of compounds.

[0036] As one example, using embodiments of MIBS systems described herein, the detection of carbon-fluorine (C-F) bonds, particularly within per- and polyfluoroalkyl substances (PFAS) can also be effectively achieved. In such applications, a microplasma discharge in an aqueous environment containing PFAS is generated using a plasma electrode, where the energetic plasma species interact with the PFAS molecules, leading to the dissociation of their robust C-F bonds. This dissociation is facilitated by the non-equilibrium nature of the electric discharge, which is characterized by a relatively high electron temperature induced by the electric field compared to the neutral gas temperature. This condition allows for the efficient excitation of C-F molecular bonds, resulting in the emission of light at characteristic wavelengths, particularly around CF A2Z+-X2FI (208-235 nanometers (nm)) and B2A-X2F1 bands (198-203 nm). Light emitted from the plasma discharge may be captured by an optical collector of the MBIS system and conveyed to a spectrometer for analysis to thereby provide a reliable means of detecting and quantifying the presence of C-F bonds.

[0037] In addition to the emission from the C-F bond, the spectrometer of the MIBS system can detect emissions from other elements present in PFAS, such as for example carbon (around 247 nm), fluorine (at approximately 685 nm), and sulfur (near 921 nm), as demonstrated in the dissociation products of perfluorooctanesulfonic acid (PFOS). The simultaneous presence of these multi-elemental emissions aids in uniquely deconvolving the spectral features specific to PFAS, reducing the likelihood of interference from other compounds that may contain similar elements. In addition, calibration procedures can be employed to gather the spectral responses of morecomplex molecules, and this data can be used to train algorithms for accurately deconvolving and identifying various potential sources. This approach significantly enhances the specificity and reliability of MIBS in environmental remediation applications.

[0038] Atoms and diatomic molecules exhibit multiple spectral line transitions, each occurring at different wavelengths. The transitions mentioned are representative examples, but they may not always be the most suitable for analysis due to several factors, including line strength, interference from overlapping spectral lines, absorption effects, and the wavelength sensitivity of transmission and detection optics. These factors must be carefully considered when selecting the optimal transition for precise spectroscopic analysis.

[0039] In different embodiments, MIBS systems include a fluid system (e.g., facilitating the flow of fluids such as liquids through the MIBS system), a plasma generation chamber or simply “plasma chamber,” a voltage source or power supply, a spectrometer (e.g., an optical emission spectrometer (OES)), and a system controller. The fluid system, voltage source, and / or spectrometer may be monitored or controlled by the system controller. Particularly, a user may be able to adjust process parameters such as the spectra acquisition time, the plasma applied voltage, the plasma energy per pulse or use pre-defined manufacturer settings.

[0040] Generally, for the MIBS systems and methods disclosed herein, the plasma is in local thermodynamic non-equilibrium (Tgas< Trotationai < T vibrational < Teiectron) and is induced electrically by exceeding the dielectric breakdown strength of the liquid sample. This is unlike the plasma generated in LIBS systems which is instead in thermal equilibrium with a relatively high electron number density suffering from the limitations outlined above. A non-equilibrium or a non-thermal plasma can be produced around a single electrode tip in the form of a corona discharge. Due to comparatively lower electron densities, OES of a non-thermal plasma results in narrow spectral lines with reduced peak broadening and is insensitive to solution salinity changes.

[0041] Additionally, the disclosed system may be configured to be in-line on a flowing liquid system and can also perform rapid batch processing in the field. It is easily attached to an existing system with the use of standard fittings and doesn’t require a complete overhaul on the user’s side. The controlled energy per pulse of the plasma discharge allows excitation of emission from elements without generating a high temp broadband emission thereby making the plasma non-equilibrium and non-thermal. Innonthermal plasmas only the electron temperatures are higher than the rest of the heavy species in the plasma (ions and neutrals). Depending on the input voltage pulse duration, the type of species observed can be changed. For short duration pulses (< 100 ns) light emission is solely due to recombination of ions, whereas for longer duration input pulses (> 100 ns) light emission is due to recombined ions and decomposition of the liquid. This property is leveraged to minimize peak broadening and interference of certain species in the fluid (e.g., N2, OH, Ha, HP). The plasma discharges for OES may be done on liquid surface, in the bulk of the liquid and in an atomized form of the liquid.

[0042] Referring initially to FIG. 1A, an embodiment of a system 10 for identifying one or more substances using MIBS is shown. In this exemplary embodiment, MIBS system 10 generally includes an electrical power supply or voltage source 12, an electrical resistor 14, an electrical capacitor 16, an electrical pulse generator 18, a pair of plasma electrodes 22 located in a plasma receptacle 23 and separated by a gap extending therebetween, an electrical ground 26, and an optical detector 30. In some embodiments, plasma electrodes 22 (and other embodiments of plasma electrodes described herein) are formed from or comprise refractory metals, and / or electrically conductive ceramic materials. For example, in some embodiments, plasma electrodes 22 comprise one or more (e.g., a composite of) Tungsten, Palladium, Gold, Silver, Molybdenum, Silicon, Carbon, Platinum, Iron, Titanium, Rhodium, Rhenium, Osmium, Iridium, Tantalum, Niobium, Ruthenium, Vanadium, Chromium, Zirconium, Nickel, Aluminum, Tin, Zinc, Lanthanum, Manganese, Barium. Generally, plasma electrodes 22 comprise ceramic composites, metal alloys, pure metals, metals having an oxidation layer, pure carbon, or pure silicone. In some applications, plasma electrodes 22 may be formed from materials having a relatively great melting point because the exposed electrode tips of plasma electrodes 22 may be sharp and the degradation rate thereof may increase with decreasing melting point.

[0043] MIBS system 10 defines an electrical circuit as shown in FIG. 1A and, particularly in this exemplary embodiment, a HV solid state nanosecond pulser (FID) configured to generate pulsed plasma discharges in a liquid sample. In other embodiments, however, the configuration of MIBS system 10 may vary from that shown in FIG. 1A.

[0044] Voltage source 12 is electrically connected along the electrical circuit shown in FIG. 1 A with the resistor 14, capacitor 16, pulse generator 18, plasma electrodes 22 and ground 26. In this exemplary embodiment, voltage source 12 of MIBS system 10 is configured to selectably generate and apply an electrical voltage to the pulse generator18 electrically connected with the voltage source 12. Voltage source 12 may take many forms including, for example, portable batteries and / or a power supply connectable to an electrical grid via a power outlet and the like. In some embodiments, voltage source 12 comprise a direct current (DC) voltage source configured to provide a DC voltage having a reversible polarity. The configuration of plasma receptacle 23 may take many forms in accordance with the principles described herein. For instance, the plasma receptacle 23 may comprise and be referred to alternatively herein as a plasma reactor, a plasma chamber, a plasma generation chamber, and the like. Similarly, plasma electrodes 22 may also take many forms and thus may comprise or be referred to alternatively herein as a “HV electrode,” a “powered electrode,” and a “plasma electrode.”

[0045] In this exemplary embodiment, voltage source 12, resistor 14, and capacitor 16 collectively form or define a resistor-capacitor or “RC” charging electrical circuit. Particularly, the voltage generated by voltage source 12 may charge capacitor 16 whereby an electric field potential builds in capacitor 16 until the electric field potential is sufficient to cause a breakdown across pulse generator 18 whereby a HV electrical pulse is applied to the pair of plasma electrodes 22. Particularly, in this exemplary embodiment, pulse generator 18 comprises a pair of pulser electrodes 20 separated by an air or spark gap 21 . Particularly, in this exemplary embodiment, spark gap 21 (along with potentially spark gaps of other embodiments of MIBS systems and methods described herein) is formed in a hermetically sealed environment (e.g., a hermetically sealed chamber of pulse generator 18) that may be filled by a noble gas such as, for example, nitrogen or air. Additionally, the magnitude or distance of the spark gap 21 may comprise a user-selected or tuned parameter in some embodiments. Further, in this exemplary embodiment, MIBS system 10 includes only the single spark gap 21 for generating the electrical pulse supplied to the pair of plasma electrodes 22 and thus MIBS system 10 may be referred to as a single spark gap system.

[0046] The breakdown across pulse generator 18 permits electrical current to arc across spark gap 21 such that the voltage pulse is applied to the pair of plasma electrodes 22. Although resistor 14 and capacitor 16 are described in FIG. 1A as being separate from voltage source 12, in other embodiments, resistor 14 and / or capacitor 16 may form components or features of the voltage source 12. Additionally, this process may continue repeatedly or cyclically whereby a plurality of voltage pulses are applied to the plasma electrodes 22 via the operation of the RC charging circuit and the pulse generator 18 of MIBS system 10 In some embodiments, a magnitude or distance of the spark gap 21 ofpulse generator 18 may control or tune the resulting magnitude of the voltage pulses applied to plasma electrodes 22 of MIBS system 10 and / or the repetition or frequency of the voltage pulses applied to plasma electrodes 22. In certain embodiments, the magnitude of spark gap 21 may be adjustable to control one or more parameters of the electrical voltage applied by plasma electrodes 22. In some embodiments, parameters of the voltage generated by voltage source 12 may be selectably controlled to influence or affect the voltage pulse applied to plasma electrodes 22 such as by a computer- implemented controller of MIBS system 10.

[0047] In some embodiments, the pulse generator 18 is configured (e.g., when powered by voltage source 12) to provide one or more electrical pulses to the pair of plasma electrodes 22 each having a voltage approximately greater than between 13 kilovolts (kV) and 40 kV. Applying a voltage equal to or greater than 13 kV may achieve sufficient energy deposition into the plasma discharge, leading to sufficient to light production for spectroscopic analysis. Thus, in at least some applications, voltages less than 13 KV may result in limited light making it difficult to capture enough light to be able to obtain a meaningful spectrum. Additionally, it may be preferred to exceeding approximately 40 kV in some applications given that increasing voltages result in increased energy deposition in the submerged gap, resulting in increased electron density. This increased electron density, in turn, accelerates H2O decomposition, leading to effects such as Stark broadening, Stark splitting, and the like. Additionally, operating at voltages above 40 kV may require additional design considerations for the MIBS system, such as increased insulation requirements, resulting in a bulkier system. Moreover, voltages above 40 kV may result in a stronger shockwave formation at above 40 kV that could cause material degradation.

[0048] In some embodiments, pulse generator 18 is configured to provide one or more electrical pulses to plasma electrodes 22 each having a peak electrical current approximately equal to or greater than 10 amps (A) and less than 500 A. In certain embodiments, pulse generator 18 is configured to provide one or more electrical pulses to plasma electrodes 22 whereby an electric field is generated at the tips of plasma electrodes 22 having a strength of between approximately 0.10 gigavolts / meter (GV / m) and 1 .5 GV / m. Additionally, in some embodiments, pulse generator 18 is configured to provide one or more electrical pulses to plasma electrodes 22 each having a rise time of between approximately 0.001 microseconds (ps) and 10 ps. Further, in some embodiments, pulse generator 18 is configured to provide one or more electrical pulsesto plasma electrodes 22 each having a pulse duration (e.g., a discharge duration) of between approximately 0.005 ps and 40 ps.

[0049] Although MIBS system 10 is shown in FIG. 1A as including only a single pulse generator 18, in other embodiments, MIBS system 10 may include a plurality of separate pulse generators 18 each forming a separate spark gap 21 , for example. Particularly, and referring briefly to FIG. 1 B, another embodiment of a MIBS system 40 is shown including a pair of pulse generators 18-1 and 18-2. In this exemplary embodiment, a second pulse generator 18-2 is electrically connected in parallel to the plasma electrodes 22. In this arrangement, the second pulse generator 18-2 may selectably tune (e.g., reduce) the voltage applied to the plasma electrodes 22 while also tuning (e.g., reducing) the pulse duration of the electrical pulse applied to the plasma electrodes 22. The magnitude of a spark gap 21-2 of the second pulse generator 18-2 may be equal to or different than the magnitude of a spark gap 21-1 of a first pulse generator 18-1 of the MIBS system 40.

[0050] Returning to FIG. 1A, in some embodiments, pulse generator 18 is configured to provide one or more electrical pulses to plasma electrodes 22 whereby plasma electrodes 22 provide an instantaneous plasma power of between approximately 0.1 megawatts (MW) and 15 MW. In some embodiments, pulse generator 18 is configured to provide one or more electrical pulses to plasma electrodes 22 at a pulsing frequency of between approximately 5 hertz (Hz) and 80 Hz. In certain embodiments, Additionally, in some embodiments, pulse generator 18 is configured to provide one or more electrical pulses to plasma electrodes 22 each having an energy (e.g., electrical energy) per pulse of between approximately 20 milli-Joules (mJ) and 300 mJ. In certain embodiments, plasma electrodes 22 are provided with a tip radius of between approximately 10 microns (pm) and 2000 pm. In some embodiments, plasma electrodes 22 each have an exposed electrode tip having a length between approximately 100 pm and 2,000 pm. The exposed electrode tip length may vary in other embodiments while maintaining losses via electrolysis and dissipation. In certain embodiments, plasma electrodes 22 are spaced from the optical detector 30 (e.g., from a light or optical collector 32 of optical detector 30) by a distance between approximately 1 millimeter (mm) and 20 mm. In other embodiments, one or more of the various parameters of Ml BS system 10 provided above may vary in accordance with the requirements of the given application.

[0051] The plasma receptacle 23 of MIBS system 10 is configured to receive a liquid sample 24 which may be acted upon by the pair of plasma electrodes 22 whereby aplasma discharge may be generated in the liquid sample 24 in response to applying an electrical pulse by the pulse generator 18 to the pair of plasma electrodes 22. The plasma discharge generated in the liquid sample 24 releases light that may be separated into emission spectra. Optical detector 30 is in visual or optical communication with the plasma receptacle 23 and the liquid sample 24 received therein whereby the optical detector 30 may optically (e.g., via the optical collector 32 of the optical detector 30) capture or acquire the plurality of emission spectra released by the plasma discharge generated in the liquid sample 24.

[0052] In this exemplary embodiment, optical detector 30 additionally includes a spectrometer 33 (e.g., an optical emission spectrometer) in signal communication with the optical collector 32 of optical detector 30. Although MIBS system 10 is shown in FIG. 1 A as including a single spectrometer 33, in other embodiments, MIBS system 10 (and other embodiments of MIBS systems disclosed herein) may include a plurality of separate spectrometers such as a plurality of OESs. For example, in an embodiment, a first spectrometer of the MIBS system may configured to detect a broad wavelength range (e.g., 180 nm to 1100 nm), and additional spectrometers may be configured to detect in increasingly narrower wavelength ranges (e.g, 400 nm to 700 nm, or 180 nm to 250 nm) with increasing fidelity.

[0053] The spectrometer 33 of optical detector 30 includes both an optical or light disperser 34 and an optical sensor 36. Light disperser is configured to disperse the optical signal collected by optical collector 32 into its component wavelengths and thus may comprise diffraction grating, a prism, and the like. Optical sensor 36 is configured to measure the intensity of the component wavelengths of the dispersed light or optical signal. Particularly, in some embodiments, optical sensor 36 comprises an optical sensor such as a photomultiplier tube (PMT), charge-coupled device (CCD), photodiode array (PDA), and the like configured to measure as electrical signals the intensity of light (e.g., of the plasma discharge) at specific wavelengths corresponding to particular substances. In this manner, spectrometer 33 is configured to identify a presence of one or more predefined substances in the liquid sample 24 based on or using the emission spectra captured by the optical sensor 36. In certain embodiments, optical detector 30 may instead be configured only to detect the presence of one or more chemical elements present in the liquid sample 24. In some embodiments, optical detector 30 is calibrated using appropriate reference standards to ensure that the detected wavelengths correspond to specific predefined substances such as chemical elements andcompounds. For instance, in some embodiments, the National Institute of Standards and Technology (NIST) is used as the reference standard or database. The NIST reference database contains spectral lines and associated energy levels displayed in wavelength order with all selected spectra intermixed or in multiplet order.

[0054] In certain embodiments, the spectrometer 33 identifies one or more peaks of the emission spectra described above in order to identify or detect the presence of one or more substances. Additionally, in certain embodiments, the presence of one or more substances in the liquid sample 24 may be quantified (e.g., in terms of concentration) by the spectrometer 33 by comparing the intensity of a selected emission spectra with a predefined calibration curve. Thus, in at least some embodiments, MIBS system 10 is configured to estimate a concentration of one or more substances in the liquid sample 24.

[0055] Referring to FIGS. 2 and 3, another embodiment of a system 50 for identifying one or more substances using MIBS is shown. MIBS system 50 may comprise a specific implementation or use case of the MIBS system 10 shown in FIG. 1A, and thus MIBS system 50 may share features in common with MIBS system 10 shown in FIG. 1A. Particularly, MIBS system 50 is configured to continually detect or identify the presence of one or more substances in a fluid (liquid) sample flow 51 continuously flowing through the MIBS system 50. For example, in some embodiments, MIBS system 50 may be used to detect the presence (including potentially quantifying as a concentration and the like) of one or more selected substances such as toxins and pollutants (e.g., lead, arsenic, and the like), or desirable materials such as critical and rare earth metals.

[0056] Generally, MIBS system 50 is field-deployable and thus particularly useful in applications requiring portability. Additionally, MIBS system 50 requires no special sample preparation, performs relatively quick sample analysis (e.g., within a few minutes or less) to identify and measure substances contained in the liquid sample flow 51 . In addition, MIBS system 50 is also more economical in comparison to at least some other conventional OES systems. Additionally, MIBS system 50 may be positioned in-line on a flowing liquid system, or can be configured to perform rapid batch processing in field. For instance, MIBS system 50 may be conveniently coupled or otherwise incorporated into an existing fluid system using conventional or standard couplings.

[0057] As an example, liquid sample flow 51 may comprise a flow of water produced from a subsurface region or subterranean formation and the like that is brought to the surface during the production of hydrocarbons from the subsurface region. Alternatively,liquid sample flow 51 may comprise a waste water stream generated by an industrial facility such as a mining operation, a hydrometallurgical plant, a recycling (e.g., a battery recycling) facility, and the like. In a further example, liquid sample flow 51 may comprise potable or agricultural feed or source water in which MIBS system 50 is configured to detect selected toxins and pollutants. In this manner, MIBS system 50 may be used to continually monitor for the presence of the one or more selected substances in the liquid sample flow 51 .

[0058] IBS system 50 generally includes a plasma receptacle 52, an outer housing 60, a voltage source or power supply 62, a pulse generator 64, a pair of plasma electrodes 70 and 74, an optical detector 78, and a computer-implemented system controller 90. In this exemplary embodiment, the plasma receptacle 52 of MIBS system 50 comprises a tubular fluid conduit and thus may also be referred to herein as fluid conduit 52. Fluid conduit 52 has a first or upstream end 54, a longitudinally opposed second or downstream end 56, and an opening or port 58 located longitudinally between the upstream end 54 and downstream end 56. In some embodiments, ends 54, 56 and port 58 may comprise flanged connectors (e.g., bolted connectors) as shown in FIGS. 2 and 3. Alternatively, the structural configuration of ends 54, 56 and port 58 may vary in other embodiments. The upstream end 54 of fluid conduit 52 receives the liquid sample flow 51 while the downstream end 56 is configured to discharge the same.

[0059] Additionally, port 58 of fluid conduit 52 is configured to interface or couple (e.g., releasably couple) with a corresponding connector of the housing 60 whereby the pair of plasma electrodes 70 and 74 may be (sealably) inserted into the fluid conduit 52 at a location positioned longitudinally between the ends 54 and 56 thereof whereby the pair of plasma electrodes 70 and 74 may be placed in or otherwise come into contact with the liquid sample flow 51 passing through fluid conduit 52.

[0060] The voltage source 62 may share features in common or be similarly configured as the voltage source 12 shown in FIG. 1A, and thus may comprise electrical batteries and / or a power supply configured to connect to a power source such as an electrical grid and the like. At least some of the operational parameters of voltage source 62 may be controlled by system controller 90 which is in signal communication therewith. Additionally, pulse generator 64 of MIBS system 50 is electrically powered by the voltage source 62 and is at least partially received in the housing 60. Additionally, at least some parameters of the operation of pulse generator 64 may be controlled by the system controller 90 of MIBS system 50. Similar to the pulse generator 18 shown in FIG. 1A,pulse generator 64 is configured to apply a series of HV electrical pulses to the pair of plasma electrodes 70 and 74 to generate a plasma discharge 53 in the liquid sample flow 51 as the liquid sample flow 51 flows through fluid conduit 52. In some embodiments, plasma discharge comprises a LTNE or non-thermal plasma discharge in the form of, for example, a corona discharge.

[0061] In some embodiments, MIBS system 50 is operated at power levels equal to or less than 200 watts (W), allowing the MIBS system 50 to be portable and to require less electrode maintenance. Additionally, interference from N2 spectral lines is eliminated given that plasma electrodes 70 and 74 are submerged in liquid sample flow 51 and the non-thermal nature of the resulting plasma discharge 53 minimizes OH, H-a, and H-p spectral line interference over a wider range of wavelengths as well.

[0062] Discharge electrodes 70 and 74 are each positioned in the fluid conduit 52 and are partially electrically shielded or insulated with each plasma electrode 70 and 74 having an electrically conductive, exposed electrode tip 72 and 76, respectively, that is in physical contact with the liquid sample flow 51. In some embodiments, parameters of the pulse generator 64, plasma electrodes 70 and 74, and the plasma discharge 53 generated thereby (e.g., voltage, amperage, electric field strength, discharge duration, pulse rise time, instantaneous plasma power, pulsing frequency, electrode tip radius, exposed electrode tip length) may be similar or equivalent to the corresponding parameters of MIBS system 10 shown in FIG. 1A and described above. Alternatively, one or more parameters of pulse generator 64, plasma electrodes 70 and 74, and the plasma discharge 53 may vary from the parameters provided above with respect to MIBS system 10.

[0063] In this exemplary embodiment, optical detector 78 includes an optical collector 80, an optical fiber 82 in optical communication with the optical collector 80, and a spectrometer 84 in signal communication with the optical fiber 82 and optical collector 80, where at least some of the operational parameters of optical detector (including that of spectrometer 84) may be controlled by system controller 90 which is in signal communication with spectrometer 84.

[0064] Optical collector 80 of the optical detector 78 is positioned in the fluid conduit 52 proximal plasma electrodes 70 and 74 whereby optical collector 80 may capture light from the plasma discharge 53 (located adjacent or proximal plasma discharge 53) which may be communicated via optical fiber 82 to the spectrometer 84. In someembodiments, the magnitude of the gap formed between the plasma discharge 53 and optical collector 80 may be adjusted or tuned in accordance with light sensitivity.

[0065] Additionally, spectrometer 84 is generally configured to convert the optical signal (which may be formed into emission spectra via a diffraction grating and the like) into an electrical signal whereby the intensity of the different spectral lines of the optical signal conducted by the optical cable 82 may be measured. In some embodiments, for example, spectrometer 84 may comprise an optical emission spectrometer and the like. Particularly, spectrometer 84 may receive the original optical signal and then employ diffraction grating and the like to divide the optical signal into a plurality of separate spectral lines from which emission spectra may be measured via an optical sensor such as a CCD and the like of the spectrometer 84. Additionally, spectrometer 84 may be in signal communication with a computer system that is in signal communication with the optical sensor configured to detect (or quantify as a concentration and the like) the presence of one or more substances in the liquid sample flow 51 to continually monitor the composition of liquid sample flow 51 (e.g., over days, weeks, months, years).

[0066] As described above, at least some parameters of the operation of pulse generator 64 may be controlled by the system controller 90 of MIBS system 50. For example, in some embodiments, system controller 90 may be operated by a user of MIBS system 50 to adjust characteristics of the electrical pulse applied to plasma electrodes 70 and 74, the spectra acquisition time, and other settings. In some embodiments, system controller continually logs and / or transmits (e.g., via a wireless or wired transmitter or transceiver thereof) the acquired emission spectra of liquid sample flow 51 and / or the estimated concentrations (based on the acquired emission spectra) of one or more substances contained in the liquid sample flow 51. In this exemplary embodiment, this information may be indicated to a user of MIBS system 50 via a visual display 94 (e.g., a digital display such as a liquid crystal display (LCD)) of MIBS system 50 that is in signal communication with system controller 90 and which displays exemplary optical emission spectra 96 of the liquid sample flow 51 . Additionally, this information may be presented to remote users via wireless transmission and the like.

[0067] Referring briefly to FIG. 4, an embodiment of a fluid system 100 is shown that incorporates one or more MIBS systems 50. Fluid system 100 may be any of a variety of industrial systems and, in this exemplary embodiment, includes a plurality of fluid vessels 102, 104, and 106 connected in series via a plurality of interconnecting fluid conduits. In this exemplary embodiment, a first or inlet MIBS system 50 (shown as inletMIBS system 50-1 in FIG. 4) is placed at an upstream end of fluid system 100 for monitoring an inlet liquid flow 101 of fluid system 100. Additionally, a second or discharge MIBS system 50 (shown as discharge MIBS system 50-2 in FIG. 4) is placed at a discharge end of fluid system 100 for monitoring a discharge liquid flow 103 of fluid system 100.

[0068] In some embodiments, the chemical composition of inlet liquid flow 101 may vary from that of discharge liquid flow 103 and thus inlet MIBS system 50-1 may detect different substances at different concentrations than the discharge MIBS system 50-2. For example, vessels 102, 104, and 106 may be configured to increase or decrease a concentration of one or more selected substances present in the liquid sample flow 51 with discharge MIBS system 50-2 providing an indication of the efficacy of fluid system 100 in increasing or decreasing the concentrations of the selected substances. For instance, data provided by discharge MIBS systems 50-1 and 50-2 of fluid system 10 may be used to tune operational parameters of fluid system 10 (including operational parameters of vessels 102, 104, and / or 106) to maximize the efficiency of fluid system 10 in increasing or decreasing the concentrations of the selected substances. In some embodiments, fluid system 100 may comprise a processing plant. However, the configuration of fluid system 100 may vary in other embodiments. For example, in other embodiments, fluid system 100 may comprise a wastewater or produced water plant and the like.

[0069] Although the pair of plasma electrodes 70 and 74 are submerged in the liquid sample flow 51 in the MIBS system 50 shown in FIGS. 3 and 4, both plasma electrodes of MIBS systems in accordance with the principles disclosed herein need not be entirely submerged in a liquid sample. For example, and referring now to FIGS. 5 and 6, additional embodiments of MIBS systems 110 and 120, respectively, are partially shown. MIBS systems 110 and 120 may include features in common with MIBS system 50 shown in FIGS. 2 and 3. Particularly, MIBS system 110 includes, among other features, a sample injector 112 comprising a nozzle 113 configured to emit an atomized stream or jet of liquid sample droplets 114 towards the pair of plasma electrodes 70 and 74 and the optical collector 80 of MIBS system 110. In the exemplary embodiment shown in FIG. 5, rather than being submerged in a liquid sample, the exposed tips 72 and 76 of plasma electrodes 70 and 74 are positioned in the path of the atomized stream of liquid sample droplets 114 whereby a multi-phase plasma discharge 116 is generated in the stream of liquid sample droplets 114.

[0070] As for the exemplary embodiment shown in FIG. 6, MIBS system 120 includes first plasma electrode 70 and a second plasma electrode 122 having an exposed electrode tip 124. In this exemplary embodiment, the tip 72 of discharge is positioned vertically above a surface 127 of a liquid sample 126 of the MIBS system 120. Conversely, the exposed tip 124 of second plasma electrode 122 is submerged in the liquid sample 126 vertically beneath the surface 127 of liquid sample 126. In this configuration, at least a portion of the plasma discharge 128 forms a vertically extending column located above the surface 127 of the liquid sample 126. A vertical distance extending between the exposed tip 72 of first plasma electrode 70 and the surface 127 of liquid sample 126 may be adjusted to control or tune the length of the plasma discharge 128.

[0071] Referring to FIG. 7, another embodiment of a system 150 for identifying one or more substances using MIBS is shown. MIBS system 150 may comprise another specific implementation of the MIBS system 10 shown in FIG. 1A, and thus MIBS system 150 may share features in common with MIBS system 10. In certain embodiments, MIBS system 150 requires no special sample preparation prior to MIBS system 150 receiving and ingesting the sample. MIBS system 150 generally includes a plasma receptacle 152, a liquid (e.g., water in this exemplary embodiment) receptacle 154, a fluid pump 156, a voltage source or power supply 170, a pulse generator 172 (indicated as defining a HV circuit in FIG. 7), a plasma receptacle 174, a plasma electrode 180, an optical detector 182, and a computer-implemented system controller 190.

[0072] Sample receptacle 152 is configured to receive a sample material to be analyzed by the MIBS system 150 while liquid receptacle 154 is configured to receive a liquid carrier fluid such as water to be mixed or otherwise combined with the sample received in sample receptacle 152. Receptacles 152 and 154 are each in fluid communication with the fluid pump 156 of MIBS system 150. Particularly, in this exemplary embodiment, sample receptacle 152 if fluidically connected to fluid pump 156 with a filter 153 and a first isolation valve 158-1 fluidically connected in series between sample receptacle 152 and fluid pump 156. Similarly, liquid receptacle 154 is fluidically connected to fluid pump 156 with a second isolation valve 158-2 fluidically connected therebetween. In at least some embodiments, the sample material received by sample receptacle 152 comprises a liquid sample material

[0073] A fluid junction upstream of fluid pump 156 mixes or otherwise combines the sample material received in sample receptacle 152 with the liquid received in liquidreceptacle 154 upstream of a suction of fluid pump 156 to form a liquid sample stream 155. Alternatively, MIBS system 150 may not include liquid receptacle 154 and thus may not mix the sample material with another material upstream from fluid pump 156. Fluid pump is in signal communication with system controller 190 which may operate fluid pump 156 to discharge the liquid sample stream 155 and thereby flow the liquid sample stream 155 into the plasma receptacle 174 of MIBS system 150.

[0074] The liquid sample stream 155 is received in the plasma receptacle 174 (e.g., as a discrete batch to be analyzed by the MIBS system 150) along with the plasma electrode 180 and an optical collector 184 of the optical detector 182 of MIBS system 150. Discharge electrode 180 is in signal (e.g., electrical) communication with system controller 190 through the pulse generator 172 which is electrically connected to the system controller 190 via an electrical conductor extending therebetween. Pulse generator 172 is operable by the system controller 190 to generate one or more (e.g., a series) of HV electrical pulses to the plasma electrode 180 whereby, with the plasma electrode 180 submerged or located proximal the liquid sample 155 received in plasma receptacle 174, generates a plasma discharge 157 in the liquid sample within the plasma receptacle 174. Additionally, in this exemplary embodiment, both the pulse generator 172 and the plasma receptacle 174 are each located or positioned within a faraday shield 176 to use to restrict the transmission of electromagnetic fields thereacross. Additionally, in this exemplary embodiment, the liquid sample 155 is electrically grounded via an electrical ground 178 located external to the faraday shield 176.

[0075] Light from the plasma discharge 157 may be collected by the optical collector 184 located within plasma receptacle 174 proximal the plasma discharge 157. Optical collector 184 is optically coupled to a spectrometer 186 (e.g., an optical emission spectrometer) that is in signal communication with system controller 190. In this exemplary embodiment, spectrometer 186 comprises both an optical or light disperser such as diffraction grating in the like to disperse the light (e.g., into a dispersed optical signal) collected by optical collector 184 into its component wavelengths, and an optical sensor such as a CCD and the like for measuring the intensity of the dispersed light at its component wavelengths. Information generated by the optical sensor may then be communicated to the system controller 190 (and / or a separate computer system) for further analysis. In other embodiments, at least some of the features of the spectrometer 186 may be combined with the system controller 190 such as the CCD and / or hardware associated therewith. In other words, in some embodiments, at least some of thefeatures of the spectrometer 186 may overlap or be combined with the system controller 190.

[0076] Referring to FIGS. 8-10, another embodiment of a system 200 for identifying one or more substances using MIBS is shown. MIBS system 200 may comprise another specific implementation of the MIBS system 10 shown in FIG. 1A, and thus MIBS system 200 may share features in common with MIBS system 10. Particularly, MIBS system 200 may comprise a physical manifestation or implementation of the MIBS system 150 shown schematically in FIG. 7. MIBS system 200 is portable (e.g., man portable) and is thus field-deployable. Additionally, MIBS system 200 requires no special sample preparation prior to MIBS system 200 receiving and ingesting the sample. MIBS system 200 generally includes an outer housing or case 202, a first unit or rack 210 insertable into the case 202, and a separate second unit or rack 260 also insertable into the case 202 and in signal (e.g., electrical) communication with first rack 210.

[0077] In some embodiments, racks 210 and 260 may comprise or resemble server racks that may be conveniently rack-mounted into the case 202. Racks 210 and 260 may conveniently divide or segregate a low voltage (LV) electrical side (housed within first rack 210) of the MIBS system 200 from a HV electrical and fluidic side (housed within second rack 260) of the MIBS system 200. In this manner, the LV electrical side of MIBS system 200 may be conveniently coupled with or decoupled from the HV electrical / fluidic side of MIBS system 200.

[0078] As shown particularly in FIG. 9, the first rack 210 of MIBS system 200 generally includes a rack housing 212 having an interior 213, a voltage source or power supply 214, a spectrometer 216, and a computer-implemented system controller 218 each housed within the interior 213 of rack housing 212. Particularly, in this exemplary embodiment, voltage source 214 is electrically connected to spectrometer 216 and system controller 218 along with an external first power connector 220, a power distribution unit (PDU) 222, and a DC converter 224. In this exemplary embodiment, alternating current (AC) (e.g., 120 V AC) is receivable by the first power connector 220 and deliverable to the voltage source 214 which may convert the AC into DC such as, for example, 12 V DC to provide DC power to components of MIBS system 200. In some embodiments, voltage source 214 comprises a 100 W to 500 W (e.g., 300 W) DC power supply. Additionally, while first rack 210 is shown in FIG. 10 as including a single voltage source 214, in other embodiments, first rack 210 (and / or second rack 260) may include a plurality of separate voltage sources configured for separately powering differentelectrically powered equipment of second rack 260. Further, in still other embodiments, electrical equipment of second rack 210 (and / or of first rack 260) powerable by 120 V AC may be directly powered by a power connector rather than via an internal voltage source or power supply like power supply 214.

[0079] In this exemplary embodiment, The PDU 222 of first rack 210 distributes DC power received from voltage source 214 to an electrical relay board or unit 226 of the first rack 210 for protecting, monitoring, or performing other functions related to the operation of electrical equipment of MIBS system 200 including, for example, system controller218 as well as electrical equipment of second rack 260. System controller 218 is electrically connected to the voltage source 214 via the DC converter 224 and relay board 226. DC converter 224 is configured to step down the DC voltage received from voltage source 214 such as from, for example, 12 V DC to 5 V DC. System controller 218 includes a digital processor 219 (e.g., a central processing unit (CPU) and the like) and a digital memory device 221 in signal communication with the processor 219 whereby processor 219 may execute instructions stored on the memory device 221 .

[0080] In this exemplary embodiment, system controller 218 is also electrically connected to a solid state relay 228 of the first rack 210. Solid state relay 228 is electrically connected to external second and third power connectors 230 and 231 of first rack 210 both of which may interface with a HV circuit of MIBS system 200. Second power connector 230 may receive electrical power separately from the first power connector 220. Additionally, third power connector 231 may supply electrical power to electrical equipment of second rack 260 that interfaces or comprises a HV circuit thereof. In this exemplary embodiment, second power connector 230 receives a similar source of AC electrical power as first power connector 220 (e.g., 120 V AC). Alternatively, second power connector 230 may receive a different form of electrical power (e.g., HV electrical power) than first power connector 220. Additionally, in this exemplary embodiment, first rack 210 also includes an external third power connector or interconnect 232 for supplying electrical power (e.g., DC electrical power) to the second rack 260. In some embodiments, first rack 210 may not include both power connectors 220 and 230 and instead may include only one of power connectors 220 and 230. Additionally, the positioning of the various power, data, and / or optical connectors of both first rack 210 and second rack 260 may vary in other embodiments from that shown in FIGS. 8-10.

[0081] Spectrometer 216 is in electrical signal communication with system controller 218 and an external first data connector234 (e.g., a universal serial bus (USB) connector) of first rack 210. Additionally, spectrometer 216 is in optical signal communication with an optical connector 236 of first rack 210 via an optical fiber or cord 238 extending therebetween. Spectrometer 216 may include both an optical or light disperser such as diffraction grating in the like and an optical sensor such as a CCD and the like. Information generated by the optical sensor of spectrometer 216 may be communicated to the first data connector 234. Additionally, information may be transmitted to and from system controller 218 via an external second data connector 236 (e.g., a USB connector) of first rack 210 electrically connected therewith.

[0082] As shown particularly in FIG. 10, the second rack 260 of MIBS system 200 generally includes a rack housing 262 having an interior 263, an external sample inlet 264, a liquid (e.g., water) receptacle 266, a pair of external liquid outlets 268 and 270, a first or inlet fluid pump 272, a second or discharge fluid pump 274, a plasma receptacle 276, an AC to DC converter 290, a voltage multiplier 292, and a pulse generator 296. In this exemplary embodiment, sample inlet 264 comprises a fluid connector that may be fluidically connected with an external sample receptacle housing a sample material while liquid receptacle 266 comprises an internal receptacle or chamber that may be filled with a suitable liquid such as water. In other embodiments, liquid receptacle 266 may be located external the rack housing 262 and fluidically coupled to second rack 260 via a suitable fluid connector.

[0083] In this exemplary embodiment, second rack 260 includes a pair of solenoid valves 265-1 and 265-2 housed within the interior 263 of rack housing 260. A first solenoid valve 265-1 is fluidically connected to the sample inlet 264 while a second solenoid valve 265-2 is fluidically connected to the liquid receptacle 266. Additionally, each solenoid valve 265-1 and 265-2 is electrically connected to an external power connector 298 and an external power connector or interconnect 300 of second rack 260. As with first rack 210 described above, the number of power connectors of second rack 260 may vary from that shown in FIG. 10. Power connector 298 may electrically connect to an external power source for receiving electrical power (e.g., AC power). Additionally, power interconnect 300 may electrically connect to the power interconnect 232 of first rack 210 for receiving electrical power therefrom. In this exemplary embodiment, power connector 298 may electrically connect with the HV circuit of second rack 260 while power interconnect 300 may be electrically insulated from the HV circuit. Additionally, electricalsignals may be communicated from the system controller 218 of first rack 210 to the solenoid valves 265-1 and 265-2 via the power interconnect 300 for controlling the operation (e.g., whetherthe solenoid valve 265 is in an open position ora closed position) of solenoid valves 265-1 and 265-2.

[0084] Second rack 260 includes a fluid junction 267 downstream from solenoid valves 265-1 and 265-2 which combines the sample material received from sample inlet 264 and the liquid received from liquid receptacle 266 upstream from a suction of the inlet fluid pump 272. Fluid inlet pump 272, along with being fluidically connected to the fluid junction 267, is electrically connected to the power interconnect 300 whereby electrical signals may be transmitted between fluid inlet pump 272 and the system controller 218 of first rack 210. Plasma receptacle 276 defines an internal chamber in this exemplary embodiment, and thus plasma receptacle 276 may also be referred to herein as plasma chamber 276. Further, a discharge of fluid inlet pump 272 is fluidically connected to a sealed fluid connector 278 of the plasma chamber 276 that provides a sealed fluid communication between the fluid inlet pump 272 and an interior of the plasma chamber 276. In this exemplary embodiment, in addition to fluid connector 278, plasma chamber 276 includes a sealed electrical connector 280 and a sealed optical connector 282, as will be discussed further herein.

[0085] In this exemplary embodiment, second rack 260 additionally includes a diversion or 3-way valve 275 including a plurality of separate fluid ports 277-1 , 277-2, and 277-3. Particularly, diversion valve 275 has a first position providing a flowpath between ports 277-1 and 277-3 (fluidically isolating third port 277-3 from second port 277-2), and a second position providing a flow path between ports 277-2 and 277-3 (fluidically isolating third port 277-3 from first port 277-1). Diversion valve 275 may be placed in the first position when MIBS system 200 is operated in a first, continuous operational mode whereby the inlet fluid pump 272 continuously circulates the liquid sample through the plasma chamber 276 such that fluid pressure applied by inlet fluid pump 272 to the liquid sample may be used to discharge the continuously flowing or circulating liquid sample from the plasma chamber 276 via the diversion valve 275 and the first liquid outlet 268 of second rack 260.

[0086] Alternatively, when MIBS system 200 I operated in a second, batch operational mode, diversion valve 275 may be actuated into the second position whereby the plasma chamber 276 may be repeatedly or cyclically filled with the liquid sample using the inlet fluid pump 272. Particularly, following the filling of the plasma chamber 276 with theliquid sample, the plasma chamber 276 may bs subsequently drained via the operation of discharge fluid pump 274 via second liquid outlet 270. In this exemplary embodiment, both the discharge fluid pump 274 and diversion valve 275 are electrically connected to the power interconnect 300 whereby electrical signals may be transmitted between fluid inlet pump 272 and the system controller 218 of first rack 210, such as for activating the discharge fluid pump 274 and for actuating diversion valve 275 between its first and second positions. In some embodiments, rather than including diversion valve 275, second rack 260 may instead include another pair of solenoid valves 275 for providing similar functionality as diversion valve 275.

[0087] The AC to DC converter 290 of second rack 260 is electrically connected to power connector 298 and is configured to convert AC electrical power received from power connector 298 into DC electrical power that is supplied to the voltage multiplier 292. The voltage multiplier 292 increases the voltage of the DC electrical power received from AC to DC converter 290 to generate HV electrical power, and supplies this HV electrical power to pulse generator 296. In some embodiments, an electrical resistor is electrically connected in parallel with the voltage multiplier 292 to protect the voltage multiplier 292 from HV voltage reflections that may arise during operation of MIBS system 200. Additionally, in some embodiments, components of the second rack 260 including said resistor may be surrounded by dielectric insulation to prevent arcing within the rack housing 262 during operation.

[0088] Pulse generator 296 defines a spark gap 299 extending between a corresponding pair of electrodes of pulse generator 296 whereby pulse generator 296 is configured to apply a plurality of separate HV electrical pulses to one or more plasma electrodes received in the plasma chamber 276 and electrically connected to an electrical discharge of the pulse generator 296 via the electrical connector 280 of plasma chamber 276.

[0089] In this exemplary embodiment, an optical collector of an optical detector 310 (also comprising the spectrometer 216 of first rack 210) of MIBS system 200 is also received in the plasma chamber 276 proximal or adjacent the plasma electrode also located therein whereby the optical collector may capture light generated by a plasma discharge in the sample fluid contained in the plasma chamber276. In this exemplary embodiment, the optical collector of optical detector 310 is in optical signal communication with an external optical connector 312 of second rack 260 via an optical fiber or cord 314 extending therebetween.

[0090] In this exemplary embodiment, MIBS system 200 additionally includes a computer system 320 located external the case 202 and including one or more input devices 322 (e.g. a keyboard, a touchpad) and one or more output devices 324 (e.g., a visual display) in signal communication with the spectrometer 216 and system controller 218 of the first rack 210 of MIBS system 200. While computer system 320 is shown in FIGS. 8-10 as being separate from the system controller 218, in some embodiments, computer system 320 may be considered to be part of an overall or global system controller of MIBS system 200 which comprises both system controller 218 and computer system 320.

[0091] Computer system 320 may enter into signal communication with the spectrometer 216 via first data connector 234 and with the system controller 218 via the second data connector 236 along with corresponding data connectors of the computer system 320. In this manner, data captured by spectrometer 216 such as the detection of one more substances in the liquid sample along with their concentrations, for example, may be provided to a user via the output devices 324 of computer system 320. Additionally, the input devices 322 of computer system 320 may be used to control the operation or otherwise to provide control inputs to the system controller 218. Further, data and / or control signals or commands may be transmitted between the computer system 320 and computer systems remote MIBS system 200 via wireless transceivers and other wireless communication devices of computer system 320. For example, a user of MIBS system 200 may input into the input devices 322 of computer system 320 commands to initiate orcease the generation of a plasma discharge in MIBS system 200, to inject or discharge a liquid sample into the plasma chamber 276, and / or to clean or flush the plasma chamber 276. In some embodiments, a memory device of computer system 320 may include spectroscopic calibration data and / or other firmware updates that may be provided to the spectrometer 216, system controller 218, and / or other electrical equipment of MIBS system 200.

[0092] In some embodiments, either manually via separate commands inputted by a user or as automated via a predefined protocol saved into a memory device of computer system 320, an exemplary routine for operating MIBS system 200 may be implemented using computer system 320. In an exemplary embodiment, such an operational routine or method includes initially flushing the plasma chamber 276 with distilled water for a predefined period of time, followed by evacuating the distilled water from the plasma chamber 276. Following evacuation of the plasma chamber 276, the plasma chamber 276 is filled with a liquid sample for a predefined period of time, following which HVelectrical pulses are provided to a plasma electrode of the MIBS system 200 to generate a repeated or cyclical plasma discharge within plasma chamber 276 as the optical detector 310 is operated to acquire emission spectra from the plasma chamber 276. After a sufficient period of time, optical detector 310 is deactivated followed by the deactivation of the plasma electrode whereby spectral analysis and the generation of a plasma discharge ceases. Finally, the liquid sample may be evacuated from the plasma chamber 276 to complete this exemplary operational routine.

[0093] In some embodiments, MIBS system 200 is configured to facilitate the continuous flow of the sample liquid through the MIBS system 200 in a continuous flow operational mode thereof. For instance, in an exemplary routine, diversion valve 275 may be placed in the first position when MIBS system 200 is operated in the continuous flow operational mode whereby inlet fluid pump 272 continuously circulates the liquid sample through the plasma chamber 276. As the liquid sample continuously circulates through the plasma chamber 276, HV electrical pulses are applied to the plasma electrode of the MIBS system 200 to generate a repeated or cyclical plasma discharge within plasma chamber 276 as the optical detector 310 is concurrently activated or operated to acquire emission spectra from the plasma chamber 276. After a sufficient period of time (e g., a user selected period of time), optical detector 310 is deactivated followed by the deactivation of the plasma electrode whereby spectral analysis and the generation of a plasma discharge ceases. Following deactivation of the plasma electrode, diversion valve 275 is actuated into the second position to cease the continuous flow of the liquid sample through the plasma chamber 276. Finally, the remaining liquid sample present in the plasma chamber 276 may be evacuated therefrom to complete this exemplary operational routine.

[0094] Referring now to FIG 12, a graph 350 is shown plotting emission spectra (in terms of intensity in units of arbitrary units (All)) or spectral lines for different substances contained in a liquid sample as a function of wavelength (in units of nm) as detected by an MIBS system in accordance with principles of this disclosure (e.g., any one of MIBS systems 10, 50, 150, and 200 described herein).

[0095] Particularly, in this exemplary embodiment, substances in the form of the chemical elements of zinc (represented by spectral line 352), silver (represented by spectral line 354), copper (represented by spectral line 356), and lead (represented by spectral line 358) are plotted in graph 350. Each spectral line 352, 354, 356, and 358 is defined by one or more peaks located at different wavelengths. For instance, the zincspectral line 352 is defined by peaks 353-1 and 353-2; silver spectral line 354 is defined by peaks 355-1 and 355-2; copper spectral line 356 is defined by peaks 357-1 and 357- 2; and lead spectral line 358 is defined by peaks 359-1 and 359-2.

[0096] Referring now to FIG. 12, a computer system 400 suitable for implementing one or more embodiments disclosed herein. For example, the various embodiments of MIBS systems described above may comprise the computer system 400 or at least some of the features of computer system 400. The computer system 400 includes a processor 402 (which may be referred to as a central processor unit or CPU) that is in communication with memory devices including secondary storage 404, read only memory (ROM) 406, random access memory (RAM) 408, input / output (I / O) devices 410, and network connectivity devices 412. The processor 402 may be implemented as one or more CPU chips. It is understood that by programming and / or loading executable instructions onto the computer system 400, at least one of the CPU 402, the RAM 408, and the ROM 406 are changed, transforming the computer system 400 in part into a particular machine or apparatus having the novel functionality taught by the present disclosure. Particularly, by programming and / or loading executable instructions onto the computer system 400, at least one of the CPU 402, the RAM 408, and the ROM 406 are changed, transforming the computer system 400 in part into a particular machine or apparatus for implementing various features of the MIBS systems described herein including activating or operating a spectrometer, electrically activatable fluid pumps, valves, and other electrical equipment of the MIBS system .

[0097] Additionally, after the system 400 is turned on or booted, the CPU 402 may execute a computer program or application. For example, the CPU 402 may execute software or firmware stored in the ROM 406 or stored in the RAM 408. In some cases, on boot and / or when the application is initiated, the CPU 402 may copy the application or portions of the application from the secondary storage 404 to the RAM 408 or to memory space within the CPU 402 itself, and the CPU 402 may then execute instructions that the application is comprised of. In some cases, the CPU 402 may copy the application or portions of the application from memory accessed via the network connectivity devices 412 or via the I / O devices 410 to the RAM 408 or to memory space within the CPU 402, and the CPU 402 may then execute instructions that the application is comprised of. During execution, an application may load instructions into the CPU 402, for example load some of the instructions of the application into a cache of the CPU 402. In some contexts, an application that is executed may be said to configure theCPU 402 to do something, e.g., to configure the CPU 402 to perform the function or functions promoted by the subject application. When the CPU 402 is configured in this way by the application, the CPU 402 becomes a specific purpose computer or a specific purpose machine.

[0098] Secondary storage 404 may be used to store programs which are loaded into RAM 408 when such programs are selected for execution. The ROM 406 is used to store instructions and perhaps data which are read during program execution. ROM 406 is a non-volatile memory device which typically has a small memory capacity relative to the larger memory capacity of secondary storage 404. The secondary storage 404, the RAM 408, and / or the ROM 406 may be referred to in some contexts as computer readable storage media and / or non-transitory computer readable media. I / O devices 410 may include printers, video monitors, liquid crystal displays (LCDs), touch screen displays, keyboards, keypads, switches, dials, mice, track balls, voice recognizers, card readers, paper tape readers, or other well-known input devices.

[0099] The network connectivity devices 412 may take the form of modems, modem banks, Ethernet cards, universal serial bus (USB) interface cards, wireless local area network (WLAN) cards, radio transceiver cards, and / or other well-known network devices. The network connectivity devices 412 may provide wired communication links and / or wireless communication links. These network connectivity devices 412 may enable the processor 402 to communicate with the Internet or one or more intranets. With such a network connection, it is contemplated that the processor 402 might receive information from the network, or might output information to the network. Such information, which may include data or instructions to be executed using processor 402 for example, may be received from and outputted to the network, for example, in the form of a computer data baseband signal or signal embodied in a carrier wave.

[0100] The processor 402 executes instructions, codes, computer programs, scripts which it accesses from hard disk, floppy disk, optical disk, flash drive, ROM 406, RAM 408, or the network connectivity devices 412. While only one processor 402 is shown, multiple processors may be present. Thus, while instructions may be discussed as executed by a processor, the instructions may be executed simultaneously, serially, or otherwise executed by one or multiple processors. Instructions, codes, computer programs, scripts, and / or data that may be accessed from the secondary storage 404, for example, hard drives, floppy disks, optical disks, and / or other device, the ROM 406,and / or the RAM 408 may be referred to in some contexts as non-transitory instructions and / or non-transitory information.

[0101] In an embodiment, the computer system 400 may comprise two or more computers in communication with each other that collaborate to perform a task. For example, but not by way of limitation, an application may be partitioned in such a way as to permit concurrent and / or parallel processing of the instructions of the application. Alternatively, the data processed by the application may be partitioned in such a way as to permit concurrent and / or parallel processing of different portions of a dataset by the two or more computers. In an embodiment, the functionality disclosed above may be provided by executing the application and / or applications in a cloud computing environment. Cloud computing may comprise providing computing services via a network connection using dynamically scalable computing resources.

[0102] Referring to FIG. 13, an embodiment of a method 450 for identifying one or more substances in a liquid sample using MIBS. Initially at block 452, method 450 includes activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample. In some embodiments, parameters of the electrical pulses and / or the plasma electrode may be consistent with the parameters described above with respect to MIBS system 10 (e.g., voltage, amperage, electric field strength, discharge duration, pulse rise time, instantaneous plasma power, pulsing frequency, electrode tip radius, exposed electrode tip length) shown in FIG. 1A. Additionally, at block 454, method 450 comprises activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector.

[0103] While embodiments of the disclosure have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1 ),(2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.

Claims

CLAIMSWhat is claimed is:1 . A system for identifying one or more substances in a liquid sample using microplasma induced breakdown spectroscopy (MIBS), the system comprising: a voltage source; one or more pulse generators electrically connected to the voltage source; a plasma receptacle configured to receive a liquid sample; a plasma electrode electrically connected to the one or more pulse generators and having an exposed electrode tip positioned at least partially in the plasma receptacle; an optical detector comprising an optical collector positioned at least partially in the plasma receptacle, and one or more spectrometers in optical communication with the optical collector; and a system controller comprising a processor and memory encoded with instructions that, when executed by the processor, cause the processer to: activate the one or more pulse generators to apply one or more electrical pulses to the plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the voltage of each of the one or more electrical pulses applied to the plasma electrode is between 13 kilovolts (kV) and 40 kV; and activate the optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector.

2. The system of claim 1 , wherein the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.

3. The system of claim 1 , wherein the MIBS system comprises only one of the one or more pulse generators, the one of the one or more pulse generators comprising a single spark gap.

4. The system of claim 1 , wherein a maximum radius of the exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm.

5. The system of claim 1 , wherein an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW.

6. The system of claim 1 , wherein an electric field at the exposed electrode tip of the plasma electrode, in response to the activation of the pulse generator, is between 0.15 gigavolts / meter (GV / m) and 1 .2 GV / m.

7. The system of claim 1 , wherein the plasma receptacle comprises a fluid conduit extending between an upstream end configured to receive a continuous flow of the liquid sample, and an opposing discharge end configured to discharge the continuous flow of the liquid sample.

8. The system of claim 1 , wherein the plasma receptacle comprises plasma chamber configured to receive a batch of the liquid sample.

9. The system of claim 1 , further comprising: an outer case; and one or more racks receivable in the outer case internally housing at least one of the pulse generator, the plasma receptacle, and the optical detector.

10. The system of claim 9, wherein the one or more racks internally house each of the pulse generator, the plasma receptacle, and the optical detector.

11. The system of claim 1 , wherein the one or more substances comprise one or more chemical compounds.

12. A system for identifying one or more substances in a liquid sample using microplasma induced breakdown spectroscopy (MIBS), the system comprising: a voltage source; a pulse generator electrically connected to the voltage source;a plasma receptacle configured to receive a liquid sample; a plasma electrode electrically connected to the pulse generator and having an electrode tip positioned at least partially in the plasma receptacle; an optical detector comprising an optical collector positioned at least partially in the plasma receptacle, and one or more spectrometers in optical communication with the optical collector; and a system controller comprising a processor and memory encoded with instructions that, when executed by the processor, cause the processer to: activate the pulse generator to apply one or more electrical pulses to the plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the energy per pulse for each of the one or more electrical pulses is between 20 millijoules (mJ) and 300 mJ; and activate the optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector.

13. The system of claim 12, wherein the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.

14. The system of claim 12, wherein the pulse generator comprises a single spark gap.

15. The system of claim 12, wherein a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm.

16. The system of claim 12, wherein the one or more spectrometers comprise an optical disperser configured to produce a dispersed optical signal into its component wavelengths, and an optical sensor optically coupled to the optical disperser and configured to measure an intensity of the component wavelengths of the dispersed optical signal.

17. The system of claim 12, wherein the plasma receptacle comprises a fluid conduit extending between an upstream end configured to receive a continuous flow of the liquidsample, and an opposing discharge end configured to discharge the continuous flow of the liquid sample.

18. The system of claim 12, wherein the one or more substances comprise one or more chemical compounds.

19. A system for identifying one or more substances in a liquid sample using microplasma induced breakdown spectroscopy (MIBS), the system comprising: a voltage source; a pulse generator electrically connected to the voltage source; a plasma receptacle configured to receive a liquid sample; a plasma electrode electrically connected to the pulse generator and having an electrode tip positioned at least partially in the plasma receptacle; an optical detector comprising an optical collector positioned at least partially in the plasma receptacle, and one or more spectrometers in optical communication with the optical collector; and a system controller comprising a processor and memory encoded with instructions that, when executed by the processor, cause the processer to: activate the pulse generator to apply one or more electrical pulses to the plasma electrode whereby a plasma discharge is generated in the liquid sample when the liquid sample is received in the plasma receptacle, wherein the duration for each of the one or more electrical pulses is between 0.005 microseconds (ps) and 40 ps; and activate the optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical collector.

20. The system of claim 19, wherein the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.

21. The system of claim 19, wherein the pulse generator comprises a single spark gap-22. The system of claim 19, wherein a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm.

23. The system of claim 19, wherein the plasma receptacle comprises a fluid conduit extending between an upstream end configured to receive a continuous flow of the liquid sample, and an opposing discharge end configured to discharge the continuous flow of the liquid sample.

24. The system of claim 19, wherein the one or more substances comprise one or more chemical compounds.

25. A method for identifying one or more substances in a liquid sample using microplasma induced breakdown spectroscopy (MIBS), the method comprising:(a) activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample, wherein the voltage of each of the one or more electrical pulses applied to the plasma electrode is between 13 kilovolts (kV) and 40 kV; and(b) activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical detector.

26. The method of claim 25, wherein the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.

27. The method of claim 25, wherein a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm.

28. The method of claim 25, wherein an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW.

29. The method of claim 25, further comprising:(c) flowing a continuous flow of the liquid sample through a fluid conduit in which the plasma electrode is at least partially received as the pulse generator is activated to apply the one or more electrical pulses to generate the plasma discharge in the liquid sample as it flows through the fluid conduit.

30. The method of claim 25, wherein the one or more substances comprise one or more chemical compounds.31 . A method for identifying one or more substances in a liquid sample using microplasma induced breakdown spectroscopy (MIBS), the method comprising:(a) activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample, wherein the energy per pulse for each of the one or more electrical pulses is between 20 millijoules (mJ) and 300 mJ; and(b) activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical detector.

32. The method of claim 31 , wherein the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.

33. The method of claim 31 , wherein a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm.

34. The method of claim 31 , wherein an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW.

35. The method of claim 31 , further comprising:(c) flowing a continuous flow of the liquid sample through a fluid conduit in which the plasma electrode is at least partially received as the pulse generator is activated to apply the one or more electrical pulses to generate the plasma discharge in the liquid sample as it flows through the fluid conduit.

36. The method of claim 31 , wherein the one or more substances comprise one or more chemical compounds.

37. A method for identifying one or more substances in a liquid sample using microplasma induced breakdown spectroscopy (MIBS), the method comprising:(a) activating a pulse generator to apply one or more electrical pulses to a plasma electrode whereby a plasma discharge is generated in the liquid sample, wherein the duration for each of the one or more electrical pulses is between 0.005 microseconds (ps) and 40 ps; and(b) activating an optical detector to identify the one or more substances in the liquid sample based on an optical signal from the plasma discharge that is collected by the optical detector.

38. The method of claim 37, wherein the frequency of the one or more electrical pulses is between 5 Hertz (Hz) and 80 Hz.

39. The method of claim 37, wherein a maximum radius of an exposed electrode tip of the plasma electrode is between 10 microns (pm) and 2000 pm.

40. The method of claim 37, wherein an instantaneous plasma power of the plasma electrode, in response to the activation of the pulse generator, is between 0.1 megawatts (MW) and 15 MW.41 . The method of claim 37, further comprising:(c) flowing a continuous flow of the liquid sample through a fluid conduit in which the plasma electrode is at least partially received as the pulse generator is activated to apply the one or more electrical pulses to generate the plasma discharge in the liquid sample as it flows through the fluid conduit.

42. The method of claim 37, wherein the one or more substances comprise one or more chemical compounds.

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