Method and apparatus for real-time nutrient detection

Abstract

This disclosure describes a method and an apparatus for real-time, in situ detection of nutrient levels in a liquid sample. The apparatus comprises a sample conditioning module disposed in a controlled environment chamber, the sample conditioning module that may be configured to transform the liquid sample into a solid sample; a spectral detector to receive emission spectra from the sample induced by a pulsed laser beam directed at the sample; and a controller unit in signal communication with the spectral detector, the controller unit being configured to analyze the emission spectra to determine a concentration of at least one nutrient in the sample.

Description

METHOD AND APPARATUS FOR REAL-TIME NUTRIENT DETECTION RELATED APPLICATION

[0001] This application claims the benefit of priority to the Singapore patent application no.10202403543 S filed November 13, 2024, the contents of which are incorporated herein by reference in entirety for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates to a method and system for detecting nutrient levels in a sample.BACKGROUND

[0003] Nutrient monitoring in hydroponics is essential for optimizing plant growth, yet conventional methods — such as pH and conductivity measurements — provide only indirect, non-specific estimates of nutrient levels. Advanced techniques like Inductively-Coupled Plasma- Optical Emission Spectroscopy (ICP-OES), Inductively-Coupled Plasma-Mass Spectroscopy (TCP -MS), atomic absorption, High Performance Liquid Chromatography (HPLC), etc., require expensive equipment, skilled personnel, and time-consuming sample preparation, making them impractical for real-time, on-site use. Ion-selective electrodes are essentially limited to detecting a single element.SUMMARY

[0004] In one aspect, various embodiments of the present disclosure describes an apparatus is configured to enable real-time, in situ detection of nutrient levels in a sample provided from a nutrient supply. The apparatus includes: a sample conditioning module, a spectral detector, and a controller unit in signal communication with the spectral detector. The sample conditioning module is disposed in a controlled environment chamber. The sample conditioning module is configured to optionally transform the sample from a liquid form into a solid form. The spectral detector is configured to receive emission spectra induceable by a pulsed laser beam directed at the sample, the sample being one of the liquid form and the solid form. The controller unit is configured to analyze the emission spectra to determine a concentration of at least one nutrient in the sample.

[0005] The controller unit may be configured to: analyze the emission spectra received from the spectral detector; identify the presence of the at least one nutrient in the sample; anddetermine the concentration of each of the at least one nutrient relative to data derived from standard samples of known compositions.

[0006] The apparatus may further include a sample delivery system configured to introduce the sample in the liquid form into the sample conditioning module in a continuous flow.

[0007] According to another aspect, a method of real-time, in situ detection of nutrient levels in a sample includes: using a sample conditioning module configured to optionally transform the sample from a liquid form into a solid form; directing a pulsed laser beam onto the sample, the sample being in one of the liquid form and the solid form; using a spectral detector, receiving the emission spectra from the sample induced by the pulsed laser beam; and determining a content of the sample using a controller unit, the controller unit being configured to analyze the emission spectra using calibration curves to determine the concentration of at least one nutrient.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various embodiments of the present disclosure are described below with reference to the following drawings:

[0009] FIG. 1 illustrates an apparatus for real-time, in situ detection of nutrients in liquid samples in accordance with embodiments of the present disclosure;

[0010] FIG. 2A to FIG. 2D illustrate an embodiment of a sample conditioning module in accordance with embodiments of the present disclosure;

[0011] FIG. 3Ato FIG. 3E illustrate various embodiments integrated with heating elements;

[0012] FIG. 4A and FIG. 4B, and FIG. 5A to FIG. 5C, illustrate the controlled environment chamber in accordance with various embodiments of the present disclosure;

[0013] FIG. 6 is a schematic diagram of an alternate embodiment of a detection configuration in accordance with embodiments of the present disclosure;

[0014] FIG. 7A and FIG. 7B illustrate aspects of a fiber optic delivery and collection configuration in accordance with embodiments of the present disclosure; FIG. 7C is a schematic diagram of the apparatus according to various embodiments of the present disclosure;

[0015] FIG. 8 A to FIG. 8C illustrate another embodiment of a microfluidic cell in accordance with embodiments of the present disclosure;

[0016] FIG. 9A to FIG. 9C illustrate thermal management of a microfluidic cell in accordance with embodiments of the present disclosure;

[0017] FIG. 10 shows representative LIBS spectra obtained from a frozen nutrient solution sample in accordance with embodiments of the present disclosure;

[0018] FIG. 11 illustrates representative LIBS spectra obtained from a dried residue of the nutrient solution in accordance with embodiments of the present disclosure; and

[0019] FIG. 12 is a schematic block diagram of a system in accordance with embodiments of the present disclosure.DETAILED DESCRIPTION

[0020] The following detailed description is made with reference to the accompanying drawings, showing details and embodiments of the present disclosure for the purposes of illustration and to aid understanding, and not to be limiting Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments, even if not explicitly described in these other embodiments. Additions and / or combinations and / or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0021] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0022] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0023] As used herein, the singular ‘a’ and ‘an’ may be construed as including the plural “one or more” unless apparent from the context to be otherwise.

[0024] The terms "about" and "approximately" as applied to a stated numeric value encompasses the exact value and a reasonable variance as will be understood by one of ordinary skill in the art, and the terms “generally” and “substantially” are to be understood in a comparable manner, unless otherwise specified.

[0025] Some processes may be described in terms of steps merely to aid understanding and / or for convenient reference. The delineation between one step and another step may be described as such merely for convenient reference in the present disclosure. It will be understood that in actual implementation there may not be a clear division or transition from one step to another subsequent step There may be a certain amount of overlap among the steps and / or more than one step may occur or be performed concurrently in time, etc.

[0026] As used herein, the term “concurrent”, or “concurrently”, is used loosely to refer to two or more occurrences (or events) that at least partially overlap in time. The occurrences may or may not start at the same time instant and / or end at the same time instant.

[0027] The present disclosure describes a method and apparatus for real-time, in situ detection of nutrients in samples, particularly suited for on-site and continuous monitoring in agricultural systems such as hydroponics and vertical farming. The apparatus enables rapid, non-destructive, multi -el emental analysis of nutrient solutions directly at the point of collection or use, eliminating the need for sample transport to centralized laboratories. This reduces turnaround time, prevents potential sample degradation, and supports immediate feedback for automated nutrient management.

[0028] The apparatus integrates a sample conditioning module with a laser spectroscopic module to enable sensitive and accurate detection of nutrients of interest, particularly but not limited to nitrogen and phosphorous, directly from the samples. The apparatus is configured for operation in real-world environments, including indoor farms, where rapid, reliable, and automated nutrient monitoring is essential.

[0029] Referring to FIG. 1, the apparatus 100 includes a pulsed laser source 110, splitting optics 120, focusing optics 130, a sampling configuration 140, collection optics 150, and a spectral detector 160. A controlled environment chamber 170 houses the sample during analysis, and a sample positioning stage 180 facilitates precise control of the sample location.

[0030] The pulsed laser source 110 generates short duration optical pulses in microsecond (pts), nanosecond (ns), picosecond (ps), or femtosecond (fs) range, suitable for inducing laser-induced breakdown spectroscopy (LIBS) or other related laser ablation / emission techniques within the sample. The specific pulse duration may be selected based on a target analyte, a sample matrix, and / or a desired spatial resolution.

[0031] Splitting optics 120, which may include dichroic mirrors, broad band mirrors, and / or beam splitters, are configured to direct at least a portion of the laser beam towards the focusing optics 130. The splitting optics allow for optional beam routing for calibration and / or reference measurements, enhancing measurement consistency and reliability.

[0032] Focusing optics 130 may be configured to concentrate the laser energy onto the sample within the controlled environment chamber 170, initiating a localized plasma formation through ablation and ionization of the sample. The focused spot size may be adjusted to enhance signal strength and to de-emphasize matrix effects. The term "matrix effects" as used herein refers to influences from substances in the sample other than the nutrients of potentialinterest. Matrix effects are generally believed to potentially alter the signal response obtainable, leading to inaccurate results.

[0033] The sample conditioning module 140 represents various methods (compatible with embodiments of the present disclosure) for introducing the sample into the analysis zone. The sample conditioning module 140 may include flow cells, microfluidic devices, or direct immersion probes, enabling flexible integration with existing fluidic systems such as those in hydroponic nutrient delivery lines. The sample conditioning module 140 may be disposed in the controlled environment chamber 170. A sample delivery system may be provided to introduce the sample into the sample conditioning module 140 in a continuous flow. The sample is preferably in a liquid state in the course of being delivered to the analysis zone.

[0034] Collection optics 150 include either direct view optics or a fiber optic probe coupled to the spectral detector 160, capturing the optical emission generated from the laser-produced plasma. The collection optics may be positioned to facilitate collection of emitted photons while reducing background noise. In some examples, the collection optics include a fiber optic probe to enable remote sensing and analysis, e.g., in challenging environments.

[0035] The spectral detector 160 may be configured to disperse the collected light based on wavelength, enabling identification and quantification of elemental constituents. Based on the absence or the presence of specific elemental constituents, or the amount of specific elemental constituents present, a nutrient concentration of the sample may be determined. The spectral detector 160 may be a spectrometer that is configured with a sufficient resolution to resolve spectral lines associated with target nutrients and potential interferents, supporting accurate multi-elemental analysis. The spectral detector may include fixed or tunable spectral filters.

[0036] A controller unit may be provided in signal communication with the spectral detector 160. The controller unit may be configured to analyze spectral data received from the spectral detector to determine an absence, a presence, and / or a concentration of at least one nutrient in the sample. The controller unit may be configured to analyze an emission spectra received from the spectral detector, identify the presence / absence of one or more nutrients in the sample; and determine a concentration of each identified nutrient (or one or more selected nutrients present in the sample) using calibration data derived from standard samples or samples with known nutrient composition. In various embodiments, the controller unit may be further configured to compare the concentration of each identified nutrient to a user-defined target range; and generate a control signal indicating one of a nutrient deficiency condition and a nutrient toxicity condition.

[0037] The apparatus may further include a control system operatively coupled to the controller unit. The control system may be an automated system. The control system may be configured to: in response to a nutrient deficiency condition, select one or more nutrients found to be deficient (nutrients determined to be absent or determined to be present but below a required concentration) and initiate dosing of the one or more nutrients found to be deficient; and in response to a nutrient toxicity condition, initiate dilution of the liquid sample by introducing water. For the sake of brevity, in the present disclosure, the one or more nutrients determined to be deficient may also be referred to as one or more deficient nutrients.

[0038] The controlled environment chamber 170 provides a stable and reproducible measurement environment by controlling parameters such as temperature, humidity, and atmospheric composition (e , vacuum, or inert gas purge) The controlled environment chamber 170 includes a sealed enclosure with inlet / outlet ports for inert gas (e.g., argon) or vacuum pump coupling, allowing dynamic purging during analysis. A pressure sensor and flow controller may be provided to regulate the internal atmosphere, maintaining a constant inert gas environment or vacuum during laser excitation. The controlled environment chamber 170 is controlled to reduce interference from ambient conditions and enhance the sensitivity of the spectroscopic measurements.

[0039] The sample positioning stage 180 allows for precise movement of the sample within the controlled environment chamber 170 to optimize laser focus and signal acquisition, and to enable consistent and repeatable measurements across multiple analyses. The sample positioning stage 180 may be provided beneath the controlled environment chamber 170 or directly beneath the sample conditioning module 140.

[0040] The method employs Laser-Induced Breakdown Spectroscopy (LIBS) unit configured to perform a rapid, non-contact analytical technique for multi-elemental analysis. Upon focusing a laser pulse onto the sample, a transient plasma is generated, emitting light (also referred to as an emission) at characteristic wavelengths corresponding to the elemental composition of the sample. The emission is collected and analyzed by the spectrometer to determine the absence / presence and concentration of nutrients.

[0041] According to various embodiments of the present disclosure, the apparatus incorporates a sample conditioning module 140 configured to enhance detection sensitivity and accuracy. In some embodiments, the apparatus and method of the present disclosure was found capable of providing a more accurate determination of nutrient deficiency for nitrogen and / or phosphorus-related nutrients. Nitrogen is important for plant health. Unfortunately, the abundance of ambient nitrogen can interfere with the detection of a nitrogen deficiency andcan also potentially interfere with an accurate determination of the level of nitrogen available as nutrient in the sample Phosphorus is another element important for plant health However, as atomic emission lines of phosphorus are readily absorbed by atmospheric oxygen, it can be challenging to accurately determine the level of phosphorus present in the sample or to determine the presence / absence of phosphorus. For example, if the actual level of phosphorus is low (e.g., phosphorus deficiency), a conventional apparatus may not even detect the presence of any phosphorus. Inaccurate determination of the absence / presence or the level of elemental nutrients could lead to ineffective or even harmful adjustments to the nutrient feed provided to the plant. In this and other aspects, it was found that the apparatus and method of the present disclosure was able to overcome or at least address challenges such as low sensitivity and poor detection limits that may result from atmospheric interference, plasma quenching, and / or spectral line absorption.

[0042] One embodiment of the proposed apparatus integrates a microfluidic device as the controlled environment chamber 170. According to the embodiment, the controlled environment chamber is configured to enable analysis of the sample under a gas-free or inert atmosphere. The scale or size of the microfluidic device enables a reduction of interference from ambient gases. The limited amount of air in the microfluidic device limits the extent to which ambient nitrogen and / or ambient oxygen can influence the detection of nutrients. It was experimentally verified that the proposed apparatus can achieve an improved signal -to-noise ratio and can enable sensitive detection of nitrogen and phosphorous, e g., at parts-per-billion (ppb) levels. It would be challenging for a conventional LIBS to achieve comparable levels of sensitivity in nutrient detection, especially but not limited to detection of nitrogen and / or phosphorus as elemental nutrients.

[0043] The microfluidic device may be configured as a sealed, gas-tight channel with a transparent window for laser transmission and optical collection. The sample is made to flow through a thin, uniform channel to encourage a consistent plasma formation and to limit or reduce thermal diffusion. Prior to analysis, the chamber is preferably purged with inert gas (e g., argon). For example, an inert gas may be pumped into the chamber via one or more inlet ports and / or air / gas may be drawn out of the chamber via one or more outlet ports. The resulting inert environment in the chamber was found to be effective for preventing absorption of phosphorus lines by oxygen and for suppression of nitrogen interference.

[0044] The microfluidic device can be relatively compact and portable, making it suitable for on-site deployment in hydroponic systems, vertical farms, or field settings. Liquid samples (samples in a liquid form) can be continuously or periodically machine-extracted from thenutrient reservoir (or a flow line, etc.) and provided to the microfluidic device. The sampling and analysis can thus be automated. Automated monitoring may be configured to be on a periodic basis (period sampling for real-time monitoring) or a continuous basis (continuous sampling for real-time monitoring). Integration of the sample conditioning section within a single device reduces the need for multiple components and complex setups, improving analytical efficiency and reducing operational costs.

[0045] The proposed apparatus enables real-time, on-line monitoring, allowing immediate assessment of nutrient levels. It enables the detection of multiple elements simultaneously, including essential nutrients such as (but not limited to) nitrogen, phosphorous, potassium, calcium, magnesium, and trace elements, providing insight into the nutrient composition of the sample.

[0046] The integration of microfluidic technology with the controlled environment chamber enhances the precision and efficiency of nutrient detection, enabling rapid analysis within a compact and portable device.

[0047] The disclosed apparatus is capable of achieving a high level of sensitivity in detecting nutrient concentrations at parts per billion (ppb) levels, enabling comparatively accurate monitoring even at trace levels. Utilizing non-contact measurement technique ensures minimal sample contamination and high specificity in nutrient detection, improving the reliability of results.

[0048] The disclosed apparatus and method are compact, portable, and onsite usable. It may be configured for direct deployment in hydroponic, vertical, or field-based agricultural systems. The apparatus and method have high sensitivity, which enables detection of nutrients, including nitrogen and phosphorous, at parts-per-billion (ppb) levels, overcoming a major limitation of conventional LIBS. It is also easy to integrate with existing hydroponic and vertical farming infrastructure, supporting seamless adoption The apparatus and method improve sensitivity and specificity for individual nutrient detection in liquid samples compared to conventional laser spectroscopy methods, due to environmental control and sample conditioning. Due to reduced reliance on expensive consumables and centralized lab infrastructure, the apparatus and method are more cost effective than existing commercial systems for specific nutrient detection. Analysis can be completed in less than one minute per sample, enabling high-frequency monitoring. The apparatus and method are automation-ready as it supports automated measurement, real-time feedback, and closed-loop control for automated nutrient replenishment, enabling scalable, intelligent nutrient management in large-scale vertical farms. Samples can be analyzed directly from the nutrient solution, reducingcomplexity and human error. The apparatus and method support sensitive detection of previously challenging elements, specifically nitrogen and phosphorous in liquid samples, which are difficult to detect accurately using conventional LIBS due to atmospheric interference and spectral absorption.

[0049] The following further describes embodiments of the sample conditioning module 140 configured to enhance the sensitivity and reliability of Laser-Induced Breakdown Spectroscopy (LIBS) analysis through a liquid-to-solid phase transition achieved by controlled cooling. Specifically, liquid samples are transformed into a frozen solid state prior to LIBS measurement (See FIG. 2A to FIG. 2D). This technique addresses limitations inherent in conventional liquid LIBS analysis and provides significant advantages.

[0050] The present disclosure provides a sample conditioning module 140 configured to enhance the sensitivity, reproducibility, and analytical accuracy of Laser-Induced Breakdown Spectroscopy (LIBS) by inducing a liquid-to-solid phase transition in a liquid sample through controlled cooling or heating. The sample conditioning module 140 is a temperature regulating device configured to provide one of heat and cold treatment to the liquid sample. In one embodiment, the sample is cooled below its freezing point within a microfluidic chamber, forming a uniform, solidified matrix that is stable under laser irradiation. Reducing molecular mobility suppresses chemical reactions within the sample during laser ablation, thereby reducing unwanted background noise and improving the clarity of the LIBS signal. In other words, the frozen sample provides a cleaner and more transparent analytical matrix, improving the sensitivity and specificity of LIBS measurements. Furthermore, this approach effectively eliminates splashing issues commonly encountered when ablating liquid samples directly.

[0051] The cooling element may be implemented as a thermoelectric Peltier device 141, which enables bidirectional thermal control through reversal of electrical current. By regulating current magnitude and polarity, the Peltier device 141 provides precise temperature control to allow rapid freezing of liquid samples and controlled thawing or sublimation for subsequent analysis. The Peltier device 140 is thermally coupled to a heat sink and / or fan system to enhance thermal dissipation during cooling cycles, ensuring efficient heat transfer and reducing thermal gradients across the sample chamber.

[0052] In one embodiment, the Peltier device 141 is embedded with the microfluidic device or mounted directly beneath the controlled environment chamber 170, enabling localized cooling with minimal thermal lag. The temperature profile is monitored in real time via a temperature sensor such as thermocouple or resistance temperature detector (RTD) integrated into the Peltier device 141, and feedback control is implemented using a closed-loop PID(Proportional-Integral-Derivative) controller to maintain the sample at a predetermined freezing temperature until ablation.

[0053] The microfluidic channel configurations are configured to facilitate heat transfer efficiency and freezing kinetics. In the square-cell configuration (FIG. 2A and FIG. 2D), the sample chamber has a rectangular cross-section, facilitating uniform thermal contact with the Peltier element and enabling rapid, homogeneous freezing. In contrast, the circular-cell configuration (FIG. 2B and FIG. 2C) features a cylindrical or conical chamber, which reduces thermal resistance at the center and promotes faster heat extraction from the core of the liquid column.

[0054] The channel dimensions are selected based on the sample volume and desired freezing time. Smaller cross-sectional areas increase surface-to-volume ratio, enhancing heat transfer rates and enabling faster phase transition. Furthermore, surface patterning (e.g., hydrophilic / hydrophobic gradients) may be incorporated to guide sample flow and ensure consistent freezing front propagation.

[0055] While the Peltier device 140 is a possible embodiment due to its compact size, rapid response, and precise control, alternative cooling mechanisms may be employed without departing from the scope of the invention. These include but are not limited to: (i) cryogenic cooling using liquid nitrogen or dry ice; (ii) refrigeration-based systems (e.g., thermoelectric coolers with liquid cooling loops); (iii) microchannel heat exchangers; and (iv) passive cooling via high-thermal-conductivity substrates (e.g., diamond or copper substrates). The concept of inducing a controlled liquid-to-solid phase transition in a microfluidic environment to stabilize the sample matrix prior to LIBS ablation remains consistent across all cooling technologies. The choice of cooling method is dependent on application-specific factors such as portability, power consumption, cooling speed, and required temperature range.

[0056] In an alternative embodiment, the sample conditioning module 140 employs controlled heating to induce a liquid-to-solid residue transition via evaporation and crystallization. This is particularly useful for samples where freezing may alter chemical speciation (e.g., precipitation of salts, formation of ice crystals that trap analytes). In this approach, a localized heating element (e.g., resistive heater, laser spot, reversed Peltier element) is used to evaporate the solvent at a controlled rate, leaving behind a solid residue of analytes and matrix components. This residue is then ablated in a stable, reproducible manner.

[0057] FIG. 3A to FIG. 3E illustrate an approach to liquid LIBS analysis utilizing microfluidic channel sampling configurations integrated with heating elements for controlled sample preparation. This facilitates the transformation of liquid samples into dry or solidresidues prior to laser ablation, significantly improving analytical performance and addressing limitations associated with direct liquid LIBS.

[0058] While the laser ablation process locally destroys a small volume of the sample, the overall sample remains intact and can be reused for subsequent analysis or returned to the nutrient system. This partial non-destructiveness enables repeated measurements without sample loss, supporting continuous monitoring. By incorporating the controlled environmental chamber and integrated sample conditioning, the apparatus enhances the accuracy and sensitivity of nutrient detection, reducing the influence of external factors on the analysis. These novel features collectively represent significant advancements in nutrient monitoring analysis, offering versatile and efficient solutions for various applications in agriculture, hydroponics, biomedical, and environmental monitoring.

[0059] As shown in FIG. 3A to FIG. 3D, two primary microfluidic device configurations are presented: single-channel configuration (as shown in FIG. 3A and FIG. 3B) and multichannel configuration (as shown in FIG. 3C and FIG. 3D). Each configuration is depicted in both three-dimensional and top views to provide a comprehensive understanding of their structure and functionality. FIG 3E illustrates a sample conditioning configuration incorporating a heating element and injection system for precise droplet formation and drying.

[0060] A feature of these embodiments is the integration of a heating element 310 strategically positioned within the microfluidic device 300 to ensure accurate temperature control during sample analysis. Precise thermal management enables controlled evaporation of the liquid sample 340, resulting in the formation of a dry residue suitable for LIBS measurement. The substrate 330 upon which the dry residue forms may be composed of polymers such as polydimethylsiloxane (PDMS), selected for its biocompatibility and ability to facilitate droplet formation from injected nutrient solutions.

[0061] The drying process significantly mitigates challenges commonly encountered in direct liquid LIBS, including splashing during laser ablation and short plasma durations resulting from sample disruption. By concentrating the analyte into a solid residue, a more stable and reproducible plasma is generated, leading to improved signal quality and quantitative accuracy.

[0062] Furthermore, the multi-channel configuration(s) (as shown in FIG. 3C and FIG. 3D) enables parallel processing of multiple liquid samples, increasing throughput and efficiency in LIBS analysis. Each channel is independently thermally controlled, enabling simultaneous freezing or drying of multiple samples. This feature is particularly advantageous for high-volume screening applications or when analyzing a diverse range of nutrient solutions. Theinjection system shown in FIG. 3E utilizes a sample dispenser 320 to provide precise deposition of sample droplets onto the substrate 330, ensuring consistent residue size and morphology across different samples.

[0063] Overall, these microfluidic sampling configurations with integrated cooling or heating elements represent innovative solutions for liquid LIBS analysis, offering improved accuracy, efficiency, scalability, and reproducibility in a wide range of analytical and research areas.

[0064] The apparatus 100 integrates a sample conditioning module 140 with a laser spectroscopic apparatus for the real-time in situ detection of nutrients in liquid samples. To maintain target analytical conditions and minimize interference, the entire sampling device may be housed within the controlled environmental chamber 170. This controlled environment facilitates accurate and reliable Laser Induced Breakdown Spectroscopy (LIBS) analysis by eliminating or reducing potential interferences from atmospheric components such as nitrogen, oxygen, and moisture. The controlled environmental chamber 170 allows for operation under various conditions including, but not limited to, inert gas purging, vacuum environments, and precise humidity control. The controlled environmental chamber 170 is sealed and equipped with gas inlet / outlet ports and pressure sensors. The inert atmosphere minimizes oxidation of ablated species and reduces background emission from ambient gases (e g , O2, N2). The chamber may also be temperature-regulated to prevent condensation or thermal drift during extended analysis sessions.

[0065] FIG. 4A to FIG. 5C illustrate various embodiments of the controlled environment chamber 170, which is specifically engineered to house and protect the sample conditioning module 140 during spectroscopic analysis of a liquid sample. The chamber body 410 is constructed from a material transparent to the operating wavelength of the excitation laser, such as quartz glass (FIG. 4A), to minimize optical attenuation and scattering during laser delivery and emitted radiation collection. This material choice enables high transmission across a broad range of UV, visible and IR wavelengths via laser-induced breakdown spectroscopy (LIBS), while maintaining sufficient mechanical strength to withstand internal pressure differentials. Operable ranges of UV and visible wavelengths may be selected from a range from 190 nm to 2500 nm.

[0066] The chamber is equipped with a multi-functional gas management system comprising an inlet port 420 for introducing a controlled atmosphere (e g , argon, nitrogen, or vacuum), an outlet port 430 for exhaust or pressure regulation, and a vacuum gauge 440 integrated into the wall of the chamber body 410 to enable real-time monitoring of internalpressure. An adjustable flow control valve 450, operably connected to the inlet and / or outlet, allows regulation of gas flow rate and chamber pressure. The chamber supports operation in both high-purity inert environments (e.g., >99.999% Ar) and vacuum conditions (down to <104mbar), enabling suppression of ambient interference and oxidation of reactive species during ablation. In the experiments conducted, the pressure was kept below a maximum pressure of about 2 bar. Operable (and / or optimal) ranges for the chamber pressure may be determined based on the laser energy, focusing geometry, spectrometer / detector grating, the target material, and the background has type (e.g., air, Ar, N, He, etc ), and / or chamber geometry, etc.

[0067] The chamber further features a removable, sealable cover 460 that facilitates access for loading the sampling apparatus 140, replacing or cleaning internal components, and maintenance. The cover 460 may be secured via a threaded locking mechanism or quick-release clamps and may include an elastomeric O-ring seal (e.g., Viton or silicone) to ensure a hermetic seal when closed. This sealing feature is critical for maintaining the desired internal environment — particularly during low-pressure or inert-gas operations — without compromising optical transparency. The top view (FIG 4B) depicts the arrangement of ports and potential mounting locations for ancillary equipment within the chamber.

[0068] FIG. 5A to FIG. 5C provide a three-dimensional perspective view (FIG. 5A), a side view (FIG. 5B), and a top view (FIG. 5C) illustrating the configuration of the chamber 510, highlighting its suitability for housing the sample conditioning module 140 and providing unobstructed optical access. The chamber 510 is configured with optical windows strategically positioned to allow for both laser input and spectral output for efficient collection of emitted spectra from the sample. Specifically, the chamber is configured to provide unobstructed, line-of-sight optical access to the sample location within the sample conditioning module 140. This configuration eliminates interference from structural components, ensuring that the laser beam is delivered with minimal distortion and that the emitted plasma radiation is collected with high fidelity by the detection system. Similar to the chamber shown in FIG. 4A or FIG. 4B, the chamber 510 is also equipped with a multi-functional gas management system comprising an inlet port 520 for introducing a controlled atmosphere (e.g., argon, nitrogen, or vacuum), an outlet port 530 for exhaust or pressure regulation, and a vacuum gauge 540 integrated into the wall of the chamber body 510 to enable real-time monitoring of internal pressure. An adjustable flow control valve 550, operably connected to the inlet and / or outlet, allows precise regulation of gas flow rate and chamber pressure. The chamber 510 may also be equipped with a fiberoptic outlet 560 which may be connectable to a fiber optic probe for collection of emitted spectra.

[0069] An alternate embodiment of the detection apparatus is illustrated in FIG. 6, providing a fiber-coupled configuration for remote spectroscopic analysis. In this embodiment, a fiber optic probe 190 delivers the spectral information to the spectral detector 160 located outside the controlled environment chamber 170. This remote configuration enables real-time analysis without exposing sensitive electronics to harsh conditions such as vacuum, high temperatures, or corrosive gases.

[0070] The fiber-coupled configuration offers several advantages over conventional direct-viewing systems. It enables spectroscopic measurements in physically inaccessible or hazardous locations (e g., inside sealed reactors, in high -temperature zones, or in confined industrial environments). Furthermore, the modular nature of fiber optic detection facilitates integration with automated sampling platforms, robotic systems, or in-line process control units. The interference filter may be selected based on the specific analyte(s) of interest and may be implemented as a dielectric stack filter, a tuneable filter, or a fixed-wavelength bandpass filter The choice of filter can be tailored to optimize signal-to-noise ratio (SNR) for the target species.

[0071] To further simplify system operation and reduce user intervention, various and alternative embodiments are presented in FIG. 7A, FIG. 7B, and FIG. 7C. Optical fibers may be deployed for both laser delivery and signal collection. This configuration eliminates the need for precise alignment of free-space optics by incorporating dedicated input and output fiber ports directly coupled to the controlled environment chamber 170. The input fiber delivers the pulsed laser beam to the sample location 140, while the output fiber collects the emitted plasma radiation and transmits it to the spectral detector 160. The fiber ports are pre-aligned during manufacturing and mounted with precision mechanical guides (e g., alignment sleeves or V-grooves) to ensure consistent coupling efficiency across multiple installations.

[0072] FIG. 7A, FIG. 7B, and FIG. 7C illustrate various embodiments, including but not limited to a rectangular chamber configuration (FIG. 7A) and a hemispherical chamber configuration (FIG. 7B). FIG. 7C may be described as an integration of features from the embodiments illustrated in FIG. 1 and FIG 7A. In these various configurations, the input fiber probe 720 and output fiber probe 730 may be positioned at optimized angles (e.g., 10° to 80° relative to a normal axis 750 from the sample location) to facilitate coupling efficiency and minimize back-reflections. For example, referring to FIG. 7C, a (angular displacement of the input fiber probe 720 relative to the normal axis 750 extending from the sample location) maybe an angle selected from a range from 10° to 80°. For example, p (angular displacement of the output fiber probe 730 relative to the normal axis 750 extending from the sample location) may be an angle selected from a range from 10° to 80°. In some examples, the input fiber probe 720 and output fiber probe 730 may be disposed at a relative angle of 120° or about 120° to one another. The fiber ports 721 and 731 are sealed with O-rings or flange fittings to maintain environmental integrity (e g., vacuum or inert gas) within the chamber. The use of standardized connectors, such as SMA (Sub Miniature Version A) or FC (Ferrule Connector), ensures interchangeability and ease of maintenance, enabling rapid replacement or reconfiguration without recalibration. The input fiber probe 720 includes focusing lens coupled to the pulsed laser 110 for delivery of the pulsed laser beam to the sample location. The output fiber probe 730 includes collection lens coupled to the spectral detector 160 for collection of the emission spectra and delivery of the same to the spectral detector 160.

[0073] This plug-and-play fiber configuration significantly reduces setup time and eliminates the need for skilled optical alignment, making the system ideal for online process monitoring, field deployment, or use in environments with limited technical expertise. The prealigned fiber ports 721 and 731 ensure repeatable performance across multiple measurement cycles and reduce long-term maintenance requirements. Moreover, the modular configuration allows for quick upgrades or reconfiguration for different analytes or measurement conditions

[0074] To further streamline the apparatus and enable continuous flow analysis, alternative embodiments utilizing microfluidic cells are presented in FIG. 8A to FIG. 8C. These configurations employ a transmission mode geometry, where the pulsed laser beam passes through the sample liquid rather than reflecting off its surface. This simplifies optical access and reduces signal distortion caused by surface reflections or scattering. The microfluidic cell 810 is integrated directly into the controlled environment chamber, enabling real-time, in-line analysis of liquid samples.

[0075] FIG. 8 A and FIG. 8B illustrate an embodiment incorporating a quartz window 830 directly integrated into the controlled environment chamber. The pulsed laser beam 811 is directed through the quartz window 830, interacting with the sample contained within the chamber. The emitted plasma radiation is collected from the opposite side of the chamber via a second quartz window or an optical collection lens. The collected radiation is then routed to the spectral detector 160. The annular Peltier element 820 surrounding the microfluidic cell provides precise temperature regulation of the sample during analysis. The inlet port 840 and outlet port 850 allow for continuous flow of liquid samples through the chamber, enabling real-time monitoring of dynamic processes such as chemical reactions, fluid mixing, or contamination detection.

[0076] In an alternative embodiment shown in FIG. 8C, a fluidic channel is constructed entirely from quartz material, eliminating the need for a separate window. This all-quartz construction provides a fully transparent optical path through the sample, reducing signal attenuation and ensuring compatibility with a wide range of liquid samples. The inlet and outlet ports 840 and 850 are configured with quick-connect fittings to facilitate easy integration with peristaltic pumps, syringe drivers, or automated liquid handling systems.

[0077] These microfluidic cell configurations are particularly advantageous for applications requiring small sample volumes, high throughput measurements, and integration with automated fluid handling systems. The use of quartz material provides excellent optical properties and chemical inertness, ensuring accurate and reliable spectroscopic data. The annular Peltier element allows for precise control of the sample temperature, which is critical for maintaining consistent analytical performance.

[0078] To enhance temperature control and ensure stable analytical performance within the microfluidic cell configurations described in Figure 8, various thermal management strategies are employed. These methods facilitate efficient heat exchange with the surrounding environment, maintaining precise sample temperatures during continuous flow analysis.

[0079] FIG. 9A and FIG. 9B illustrate an embodiment utilizing a copper block 930 directly coupled to the microfluidic cell 910. Copper’s high thermal conductivity allows for rapid heat transfer between the cell and an external temperature control system, such as a circulating water bath or chiller. This configuration is particularly effective for applications requiring precise cooling or heating of the sample liquid. The internal view of the copper block with intricate cooling liquid path (FIG. 9B) demonstrates the compact integration of the copper block 930 with the microfluidic cell 910 assembly.

[0080] FIG. 9A and FIG. 9B illustrate an embodiment wherein a copper block 930 is directly coupled to the microfluidic cell 910 via a thermally conductive interface. A Peltier element 920 may be incorporated to the microfluidic cell 910. The copper block 930, having a thermal conductivity provides a high-efficiency thermal pathway between the microfluidic cell 910 and an external temperature control system, such as a circulating water bath, chiller, or Peltier-based heat sink. The copper block is precision-machined to conform to the outer geometry of the microfluidic cell 910, increasing thermal contact area and reducing interfacial thermal resistance. This configuration enables rapid heat transfer. The internal view of the copper block with intricate cooling liquid path (FIG. 9B) further illustrates the compactintegration of the copper block 930 with the microfluidic cell 910, facilitating space-efficient configuration in modular or portable spectroscopic systems.

[0081] An alternative thermal management strategy, depicted in FIG. 9C, employs a forced air cooling system utilizing a fan 940. The fan 940 is positioned to direct airflow over a heatdissipating surface or finned structure integrated into the microfluidic cell housing. The airflow induces convective heat transfer, effectively dissipating heat generated during laser-induced plasma excitation or from ambient temperature fluctuations or from the hot side of the Peltier element 920. The fan speed is controlled via a feedback loop responsive to real-time temperature measurements from a sensor embedded in or adjacent to the microfluidic cell, enabling dynamic adjustment of cooling rate. This approach provides a simple, low-cost, and energy-efficient solution suitable for field-deployable systems, battery-powered devices, or environments where liquid cooling is impractical. The absence of fluidic connections or complex thermal interfaces reduces maintenance requirements and enhances system reliability.

[0082] These thermal management options, namely, copper block coupling and forced air cooling, offer a flexible, application-tailored approach to maintaining sample temperature stability during spectroscopic analysis. The choice between systems is governed by operational requirements including desired temperature stability, sample volume, thermal load, power availability, and environmental constraints. F or example, the copper block is preferred for high-precision, continuous-flow applications requiring sub-degree stability, while the forced air system is ideal for portable or low-power devices. The integration of either system with the microfluidic cell configurations described in FIG. 8A to FIG. 8C enables robust, repeatable performance across diverse operating conditions, thereby enhancing the reliability and versatility of the spectroscopic analysis platfonn.

[0083] The feasibility of real-time, in-situ nutrient detection using Laser-Induced Breakdown Spectroscopy (LIBS) was experimentally validated through analysi s of two distinct sample forms: (1) a frozen nutrient solution, and (2) a dried residue formed by evaporative concentration within the microfluidic channel equipped with an integrated heating element. These experiments were conducted under identical laser excitation and detection conditions, enabling direct comparison of spectral performance across sample states. For reference, a LIBS spectrum was also acquired from the bare polydimethyl siloxane (PDMS) substrate under the same experimental parameters to assess background interference and substrate contribution. The results demonstrate that the disclosed apparatus enables sensitive, selective, and dynamic nutrient detection across multiple physical states of the analyte, thereby overcoming limitationsof conventional LIBS approaches that require extensive pre-processing or are limited to solid or liquid bulk samples.

[0084] FIG. 10 presents a representative LIBS spectra obtained from a frozen nutrient solution sample Distinct atomic emission lines corresponding to key nutrient elements were identified, including calcium (Ca I & Ca II), magnesium (Mg I), sodium (Na I), nitrogen (N), and potassium (K). The observed spectral features confirm the capability of the disclosed apparatus to detect these nutrients in a frozen state. The intensity scale is shown on the y-axis, representing signal strength, while the x-axis denotes wavelength in nanometers (nm).

[0085] FIG. 11 illustrates a representative LIBS spectra obtained from the dried residue of the nutrient solution following evaporation within the microfluidic channel. The spectra exhibits prominent atomic emission lines for magnesium (Mg I), calcium (Ca II), sodium (Na I), phosphorus (P), nitrogen (N), and potassium (K). A comparison with the LIBS signal from the bare PDMS substrate reveals minimal interference from the substrate material, demonstrating the selectivity of the method for nutrient element analysis.

[0086] To enable quantitative, real-time on-site nutrient monitoring, a dedicated detection algorithm was developed and integrated into the disclosed apparatus. This algorithm utilizes reference libraries generated from standard samples of known nutrient concentrations to determine the concentration of nutrients in supplied liquid samples The apparatus may comprise an automated control system operatively coupled to the controller unit. The block diagram and operational flow of the automated system are illustrated in FIG. 12, demonstrating integration of sensing, analysis, decision-making, and actuation within a single closed-loop platform.

[0087] The detection algorithm is implemented as a modular software system comprising three interconnected functional unit: a LIBS Spectra Analysis Unit 1210 configured to process raw spectral data, a Nutrient Quantification module 1220 configured to determine concentration levels via calibration curve mapping, and a Farm User Input Interface 1230 enabling user-defined threshold settings. These modules are communicatively linked via a central controller, enabling real-time data exchange and adaptive control decisions.

[0088] LIBS Spectra Analysis Unit 1210: Incoming LIBS spectra from the sample are processed by this unit A peak identifier 1211 sub-routine compares 1212 detected spectral peaks to pre-established reference libraries containing characteristic emission lines for each target nutrient (Ca, K, Mg, N, etc ). This comparison enables identification of the nutrients present in the sample. In response to identifying the nutrients present in the sample, the LIBS Spectra Analysis Unit 1210 parse the information to the Nutrient Quantification Module 1220.

[0089] Nutrient Quantification Module 1220: Once nutrients identified by the LIBS Spectra Analysis Unit 1210, the concentration of each nutrient is determined using calibration curves generated from standard samples. These calibration curves relate LIBS signal intensity to known nutrient concentrations (expressed in parts per million - ppm). The module 1220 outputs the current nutrient concentration for each detected element.

[0090] Farm User Input Interface 1230: This interface allows users to input target nutrient concentration values specific to their application or crop type.

[0091] The output of the Nutrient Quantification Module 1220 is then compared with the user-defined optimum concentrations from the Farm User Input Interface 1230. The Controller unit executes a real-time comparison 1240 between the measured nutrient concentrations and the user-defined target ranges. Based on this comparison, the system autonomously initiates corrective actions 1250 through a closed-loop feedback mechanism:Toxic / Deficient Condition 1241: If a nutrient concentration deviates significantly from the target range, the system triggers either dilution (for toxic levels) or top-up (for deficient levels).Dilution Process 1242: In cases of toxicity, water is added to the Hydroponic Reservoir via a Water Dilution pathway.Top-Up Process 1243: For deficiencies, appropriate nutrients are selected and dosed into the Mixing Tank based on the identified missing or low-concentration elements.

[0092] The resulting nutrient solution in the mixing tank 1244 is then returned to the Hydroponic Reservoir 1245 and the next sample is being processed by the apparatus 100, completing the automated feedback loop.

[0093] The entire process is logged in a real-time operational log, including timestamps, nutrient levels, and corrective actions taken, enabling traceability and system diagnostics.

[0094] The controller unit is a dedicated, embedded computing system that serves as the central intelligence of the closed-loop nutrient management system. It is responsible for orchestrating the entire operational cycle — from real-time spectral data acquisition via laser-induced breakdown spectroscopy (LIBS), through advanced signal processing and nutrient concentration determination, to autonomous decision-making and actuation of corrective measures in the hydroponic system. The controller unit may be a purpose-built, real-time control system engineered to operate reliably in the high-moisture, variable-temperature, and electrically noisy environment of a hydroponic cultivation facility.

[0095] The controller unit integrates hardware, firmware, and software components into a single, compact, and scalable platform, enabling autonomous, adaptive, and self-verifying operation without requiring continuous human intervention.

[0096] The controller unit comprises a processor, a non-transitory computer-readable memory, and instructions stored in the memory that, when executed by the processor, cause the controller unit to perform the methods disclosed herein. The processor may be a microcontroller, microprocessor, digital signal processor (DSP), field-programmable gate array (FPGA), or application-specific integrated circuit (ASIC), configured to execute control logic, signal processing algorithms, and real-time decision-making routines. The non-transitory memory may include read-only memory (ROM), random-access memory (RAM), flash memory, or other persistent storage media, and stores executable instructions, calibration data, crop-specific profiles, operational logs, and reference spectral libraries. The controller unit is operatively coupled to one or more sensors, actuators, and communication interfaces, enabling it to receive real-time data from a laser-induced breakdown spectroscopy (LIBS) sensor, analyse nutrient concentrations, determine corrective actions based on predefined thresholds or machine learning models, and control fluid delivery systems to dynamically adjust nutrient levels in a hydroponic reservoir. The controller unit operates autonomously, supports over-the-air (OTA) firmware updates, and maintains secure, reliable operation in industrial or agricultural environments.

[0097] The present disclosure discloses a novel laser spectroscopy-based nutrient detection system enabling onsite, quasi-real-time analysis of liquid samples. The integrated apparatus comprises a pulsed laser source, a precisely controlled sample conditioning chamber -incorporating Peltier elements for temperature regulation, heating elements for enhanced analyte vaporization, dedicated control electronics, a secure sample holder, gas purging ports to minimize interference, and optical ports for efficient signal transmission - and a detection system consisting of collection optics coupled with a spectral detector.

[0098] This innovative configuration provides several key advantages over existing nutrient analysis techniques:

[0099] Onsite & Quasi-Real-Time Detection: The integrated configuration facilitates rapid, in-situ nutrient assessment, eliminating the need for laboratory analysis and associated delays.

[0100] High Sensitivity Nutrient Analysis: The system demonstrates sensitive detection of individual nutrient components - including Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Iron (Fe), Boron (B), Zinc (Zn), Manganese (Mn), Sulfur (S), and Copper (Cu) - directly from liquid samples supplied.

[0101] PPB-Level Detection Limit: The apparatus achieves detection limits in the parts per billion (ppb) range, enabling precise monitoring of even trace nutrient concentrations.

[0102] Simplified Operation & Minimal User Intervention: The system requires no sample preparation by the user, streamlining the analytical process and reducing potential errors.

[0103] These advantages position this invention as a significant advancement in nutrient analysis technology

[0104] The disclosed laser spectroscopy-based nutrient detection system possesses broad applicability across diverse commercial sectors, including but not limited to:

[0105] Hydroponic Farm Nutrient Monitoring: Real-time monitoring and optimization of nutrient levels within hydroponic systems, leading to increased crop yields and reduced resource consumption.

[0106] Automated Nutrient Supply in Large-Scale Agriculture: Integration with automated dosing systems for precise control of nutrient delivery in large farms, increasing efficiency and reducing environmental impact.

[0107] Water Quality Inspection & Environmental Monitoring: Rapid assessment of nutrient content in water sources to ensure compliance with regulatory standards and identify potential pollution events.

[0108] Nitrogen Detection in Liquid Samples (e g , Fertilizer Analysis): Accurate quantification of nitrogen levels in fertilizers, agricultural runoff, and other liquid matrices.

[0109] Forensic Investigations: Trace element analysis for investigative purposes, such as determining the source of contaminants or identifying unknown substances.

[0110] Biomedical Applications: Monitoring nutrient levels in biological fluids (e.g., blood, urine) for diagnostic and therapeutic applications.

[0111] According to various embodiments of the present disclosure, an apparatus is configured to enable real-time, in situ detection of nutrient levels in a sample provided from a nutrient supply. The apparatus includes: a sample conditioning module, a spectral detector, and a controller unit in signal communication with the spectral detector. The sample conditioning module is disposed in a controlled environment chamber. The sample conditioning module is configured to optionally transform the sample from a liquid form into a solid form. The spectral detector is configured to receive emission spectra induceable by a pulsed laser beam directed at the sample, the sample being one of the liquid form and the solid form. The controller unit is configured to analyze the emission spectra to determine a concentration of at least one nutrient in the sample.

[0112] The controller unit may be configured to: analyze the emission spectra received from the spectral detector; identify the presence of the at least one nutrient in the sample; and determine the concentration of each of the at least one nutrient relative to data derived from standard samples of known compositions.

[0113] The controller unit may be further configured to: compare the concentration of each of the at least one nutrient to a user-defined target range; and generate a control signal indicating one of a nutrient deficiency condition and a nutrient toxicity condition.

[0114] The apparatus may further include an automated control system operatively coupled to the controller unit. The automated control system may be configured to: in response to a nutrient deficiency condition, select one or more deficient nutrients and initiate dosing of the one or more deficient nutrients; and, in response to a nutrient toxicity condition, initiate dilution of the nutrient supply.

[0115] The sample conditioning module may include: one of a heating element and a cooling element configured to regulate a temperature of the sample.

[0116] The sample conditioning module may include: a thermoelectric Peltier device; a temperature sensor; and a proportional-integral-derivative (PID) controller. The PID controller may be configured to monitor a temperature profile and control the thermoelectric Peltier device to maintain at a predetermined temperature

[0117] The sample conditioning module may include: a microfluidic device defining at least one fluid channel. The sample conditioning module may include a dispenser. The dispenser may be configured to deposit liquid sample a substrate, wherein each of the at least one fluid channel is thermally controlled.

[0118] The controlled environment chamber includes: a chamber body having a laser input window and a spectral output window; an inlet port and an outlet port configured to introduce and exhaust a controlled atmosphere into and from the chamber body; a vacuum gauge in communication with an interior of the chamber body; and an adjustable flow control valve connected to at least one of the inlet and outlet ports.

[0119] The controlled environment chamber may further include a fiber optic probe connectable to the spectral output window configured to collect the emission spectra.

[0120] The apparatus may further include: a pulsed laser source; an input fiber probe having focusing lens coupled to the pulsed laser source configured to deliver the pulsed laser beam to a sample location; and an output fiber probe having collection lens coupled to the spectral detector configured to collect the emitted spectra and to deliver the emission spectra to the spectral detector, wherein the input and output fiber probes are couplable to the controlledenvironment chamber and positioned at angles between 10° to 80° relative to a normal axis from the sample location.

[0121] The pulsed laser source may be configured to generate optical pulses having durations in a range selected from microsecond (ps), nanosecond (ns), picosecond (ps), or femtosecond (fs), the laser pulses being suitable for inducing laser-induced breakdown spectroscopy (LIBS) within the sample, the sample being in the solid form.

[0122] The controlled environment chamber may further include a quartz window arranged to enable the pulsed laser beam to be directed through the quartz window prior to interacting with the sample, the sample being in the solid form.

[0123] The apparatus may be configured to detect emission lines corresponding to at least one of the following elements: Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Iron (Fe), Boron (B), Zinc (Zn), Manganese (Mn), Sulfur (S), and Copper (Cu).

[0124] The apparatus may further include a sample delivery system configured to introduce the sample in the liquid form into the sample conditioning module in a continuous flow.

[0125] According to another aspect, a method of real-time, in situ detection of nutrient levels in a sample includes: using a sample conditioning module configured to optionally transform the sample from a liquid form into a solid form; directing a pulsed laser beam onto the sample, the sample being in one of the liquid form and the solid fonn; using a spectral detector, receiving the emission spectra from the sample induced by the pulsed laser beam, and determining a content of the sample using a controller unit, the controller unitbeing configured to analyze the emission spectra using calibration curves to determine the concentration of at least one nutrient.

[0126] Numerous other changes, substitutions, variations, and modifications may be ascertained by the skilled in the art and it is intended that the present application encompass all such changes, substitutions, variations, and modifications as falling within the scope of the appended claims.

Claims

CLAIMS1. An apparatus for real-time, in situ detection of nutrient levels in a sample provided from a nutrient supply, the apparatus comprising:a sample conditioning module disposed in a controlled environment chamber, the sample conditioning module that is configured to optionally transform the sample from a liquid form into a solid form;a spectral detector configured to receive emission spectra induceable by a pulsed laser beam directed at the sample, the sample being one of the liquid form and the solid form; anda controller unit in signal communication with the spectral detector, the controller unit being configured to analyze the emission spectra to determine a concentration of at least one nutrient in the sample.

2. The apparatus of claim 1, wherein the controller unit is configured to:analyze the emission spectra received from the spectral detector; identify the presence of the at least one nutrient in the sample; and determine the concentration of each of the at least one nutrient relative to data derived from standard samples of known compositions.

3. The apparatus of claim 2, wherein the controller unit is further configured to:compare the concentration of each of the at least one nutrient to a user-defined target range; andgenerate a control signal indicating one of a nutrient deficiency condition and a nutrient toxicity condition.

4. The apparatus of any one of claims 1 to 3, further comprising an automated control system operatively coupled to the controller unit, the automated control system configured to:in response to a nutrient deficiency condition, select one or more deficient nutrients and initiate dosing of the one or more deficient nutrients; andin response to a nutrient toxicity condition, initiate dilution of the nutrient supply5. The apparatus of any one of claims 1 to 4, wherein the sample conditioning module comprises:one of a heating element and a cooling element configured to regulate a temperature of the sample.

6. The apparatus of claim 5, wherein the sample conditioning module comprises:a thermoelectric Peltier device;a temperature sensor; anda proportional-integral-derivative (PID) controller configured to monitor a temperature profile and control the thermoelectric Peltier device to maintain at a predetermined temperature.

7. The apparatus of any one of claims 1 to 4, wherein the sample conditioning module comprises:a microfluidic device defining at least one fluid channel; anda dispenser configured to deposit liquid sample a substrate, wherein each of the at least one fluid channel is thermally controlled.

8. The apparatus of any one of claims 1 to 7, wherein the controlled environment chamber comprises:a chamber body having a laser input window and a spectral output window; an inlet port and an outlet port configured to introduce and exhaust a controlled atmosphere into and from the chamber body;a vacuum gauge in communication with an interior of the chamber body; and an adjustable flow control valve connected to at least one of the inlet and outlet ports.

9. The apparatus of claim 8, wherein the controlled environment chamber further comprises a fiber optic probe connectable to the spectral output window configured to collect the emission spectra.10 The apparatus of any one of claims 1 to 9, further comprising:a pulsed laser source;an input fiber probe having focusing lens coupled to the pulsed laser source configured to deliver the pulsed laser beam to a sample location; andan output fiber probe having collection lens coupled to the spectral detector configured to collect the emitted spectra and to deliver the emission spectra to the spectral detector, wherein the input and output fiber probes are couplable to the controlled environment chamber and positioned at angles between 10° to 80° relative to a normal axis from the sample location.

11. The apparatus of claim 10, wherein the pulsed laser source is configured to generate optical pulses having durations in a range selected from microsecond (ps), nanosecond (ns), picosecond (ps), or femtosecond (fs), the laser pulses being suitable for inducing laser-induced breakdown spectroscopy (LIBS) within the sample, the sample being in the solid form.

12. The apparatus of any one of claims 1 to 11, wherein the controlled environment chamber further comprises a quartz window arranged to enable the pulsed laser beam to be directed through the quartz window prior to interacting with the sample, the sample being in the solid form.

13. The apparatus of any one of claims 1 to 12, wherein the spectral detector is configured to detect emission lines corresponding to at least one of the following elements: Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Iron (Fe), Boron (B), Zinc (Zn), Manganese (Mn), Sulfur (S), and Copper (Cu).

14. The apparatus of any one of claims 1 to 13, further comprising a sample delivery system configured to introduce the sample in the liquid form into the sample conditioning module in a continuous flow.

15. A method of real-time, in situ detection of nutrient levels in a sample, comprising:using a sample conditioning module configured to optionally transform the sample from a liquid form into a solid form;directing a pulsed laser beam onto the sample, the sample being in one of the liquid form and the solid form;using a spectral detector, receiving the emission spectra from the sample induced by the pulsed laser beam; anddetermining a content of the sample using a controller unit, the controller unit being configured to analyse the emission spectra using calibration curves to determine the concentration of at least one nutrient.

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