Improvements in and relating to apparatus and method for recycling solvent in high performance liquid chromatography (HPLC) systems for regulated industries

Abstract

A computer-controlled system for use with a high performance liquid chromatography (HPLC) system having a chromatography column, wherein the computer-controlled valve system is adapted to be connected to a detector for detecting the components of the solvent emerging from the chromatography column, the computer controlled system comprising: a valve means configured to receive an output solvent from the HPLC system; the valve means being moveable between a RECYCLE position in which the solvent is directed to be recycled for re-use in the HPLC system and a WASTE position in which the solvent is directed to be sent for waste disposal; a control system configured to be connected to the detector and to the valve means for controlling the operation of the valve means between the RECYCLE position and the WASTE position such that the detected input signal determines whether the valve means diverts the output solvent for recycling or waste disposal; the control system comprising: a Peak Detection Algorithm, and wherein the control system further comprises a Dynamic Threshold Mechanism, wherein the dynamic threshold mechanism is adapted to dynamically adjusts peak detection sensitivity based on real-time chromatographic data trends.

Description

IMPROVEMENTS IN AND RELATING TO APPARATUS AND METHOD FOR RECYCLING SOLVENT IN HIGH PERFORMANCE LIQUID CHROMATOGRAPHY(HPLC) SYSTEMS FOR REGULATED INDUSTRIESThis invention relates to an improved system, apparatus and method for recycling solvent and in particular, a system, an apparatus and methods for recycling pure / uncontaminated solvent from a High Performance Liquid Chromatography (HPLC) system and that is adapted for andsuitable for use in regulated industry such as the pharmaceutical industry. In particular, the pharmaceutical industry has compliance requirements that are fully met by the improved system, apparatus and method of the present invention for recycling solvent from a HPLC apparatuses.BACKGROUND

[0001] In chemical analysis, High Performance Liquid Chromatography (HPLC) is a well-known laboratory technique for the separation of a mixture into its individual components. The mixture to be tested is dissolved in a fluid solvent, injected into a moving flow-path called the mobile phase and is carried through a column, in which a material called the stationary phase is fixed. The different constituents of the mixture have different affinities for the stationary phase and are retained for different periods of time, causing them to separate. Therefore, the components of a test sample separate from one another by a process of differential migration as they flow through the chromatography column. As bands emerge from the column, flow carries them to one or more detectors which deliver a voltage response as a function of time. This is called a chromatogram. For each peak on the chromatogram, the time at which it emerges identifies the sample constituent with respect to a known standard. The peak’s area represents the quantity of a constituent in the test sample. HPLC has applications in a wide range of sectors including pharmaceuticals, biological products, forensics, legal, research and medicine.

[0002] Figure 1 is a schematic diagram of a typical known HPLC system. The system 1 comprises a solvent vessel 3 which contains pure, unused solvent (the “mobile phase”). The solvent vessel 3 is connected to a pump 5 which pumps the solvent into an HPLC column 9 via a sample injector 7 which injects the sample into the solvent flow path. The injector is represented by a syringe in Figure 1 but in practice, the function of the injector 7 may be carried out by a robotic autosampler. The components of the sample are separated by the column 9 and detected by the detector 11. The detected components of the sample mixture each generate a peak so the detected components of the mixture are represented by a series of peaks and this peak data is acquired by the PC 13. Thereafter, the solvent is passed into a waste vessel 15 and the solvent is subsequently sent to waste for safe disposal of the solvent.

[0003] In the case of analysis of a common painkiller tablet with 3 components, the tablet is dissolved in a liquid. This liquid is then injected into the HPLC flow path via the injector 7. The three components within the tablet now flow to and interact with the adsorbent (the “stationary phase”) within the HPLC column 9. As each component reacts differently with the absorbent, each component exits / elutes at a different time. The detector 11 sees each component and is recorded by the PC. The time and size of the component peaks are depicted as a time versus intensity graph called a chromatogram. Peak size enables quantification of each constituent component.

[0004] Figure 2 represents an exemplary chromatogram 21 of the known type which shows 3 peaks detected using a known HPLC system in which a common painkiller containing paracetamol 25 (aka Acetaminophen), caffeine 27 and Benzoic acid 29 over time 23.

[0005] In practice, there are a number of problems associated with the use of solvents in HPLC systems and in particular, in relation to seeking to recycle the solvent that is used in HPLC systems. For example, a typical Pharmaceutical manufacturing site will have 15-40 HPLC systems per site and 10’s of thousands globally. Each HPLC system generates 60-180ml of solvent waste per hour which is more than 650litres / year for each HPLC system.

[0006] The high purity solvents used in HPLC systems are expensive: Methanol €48 / L, Acetonitrile €195 / L, Ethanol €172 / L (December 2024 Merck). The “mobile phase” used by each HPLC apparatus is typically a hazardous mixture of solvent(s) plus acids and requires careful preparation by a laboratory analyst plus filtration and degassing which can take hoursof preparation time by laboratory personnel. In addition, the cost of disposal of the toxic chemical waste and associated regulation is immense.

[0007] The present invention seeks to alleviate the problems associated with known HPLC systems and apparatus especially when used within heavily regulated industries.BRIEF SUMMARY OF THE DISCLOSURE

[0008] It is an object of the present invention to provide improvements to high performance liquid chromatography (HPLC) by enabling the recycling of HPLC solvent which reduces waste, operating costs, and improves system efficiencies. The present invention is also configured for use in a regulated environment such as Pharmaceutical industry and medical technologies industry where an audit trail and additional safeguards are required.Features of the present invention are set out in the appended Claims. Further features are described herein.In a first aspect of the present invention, there is provided a computer-controlled system for use with a high performance liquid chromatography (HPLC) system having a chromatography column, the computer-controlled valve system comprising:Adapted to be connected to a detector for detecting the components of the solvent emerging from the chromatography column, the computer controlled system further comprising:a valve means configured to receive an output solvent from the HPLC system; the valve means being moveable between a RECYCLE position in which the solvent is directed to be recycled for re-use in the HPLC system and a WASTE position in which the solvent is directed to be sent for waste disposal;a control system operatively, in use, connected to the detector and to the valve means for controlling the operation of the valve means between the RECYCLE position and the WASTE position such that the detected input signal determines whether the valve means diverts the output solvent for recycling or waste disposal; the control system comprising:■ a Peak Detection Algorithm, wherein the algorithm is configured to:■ analyze the rate of change of the chromatographic signal that calculates a slope value based on two averaged signal segments;■ compare the slope value to a pre-set Peak Detection Slope threshold to identify a peak event;■ activate the valve to direct the solvent to the waste stream during a peak event; and■ maintain the solvent in the recycling stream when no peak is detected; andwherein the control system further comprises a Dynamic Threshold Mechanism, wherein the dynamic threshold mechanism is adapted to dynamically adjust peak detection sensitivity based on real-time chromatographic data trends.The system of the present invention is also configured to be connected to an auto-injector to synchronise time / date stamped audit trails, delay time function and auto-zero activation. This ensures that the system, apparatus and method of the present invention is suitable for use with HPLC apparatus in highly regulated industries such as the pharmaceutical industry.The valve means may comprise a valve or alternative means that functions in the same way as a valve.The advantages of the system, apparatus and method of the present invention include the following:1. Individual User profile login and password controlled access to the system,2. Audit Trail recording of all instrument events (User logins / logouts, parameter settings changes, start-in events etc.)The present invention has the significant advantage of providing a system, apparatus and method for recycling solvent from HPLC apparatus specifically for the cGMP industry. To be compliant within this industry, all devices must adhere to 21 CFR part 11 compliance and the present invention is adapted to meet this requirement and Standard for compliance.3. Storage of all individual injections / chromatograms4. A separate proprietary Microsoft Windows software enables download of individual chromatograms and audit trail reports5. The apparatus, system and method of the present invention calculates all Waste and Recycle volumes6. Unique peak detection algorithm incorporating ‘Smart Threshold’ technology, this comprises the dynamic threshold process that is described herein;7. Divert valve comprises a delay-time feature based on flow rate and tubing length; 8. Baseline ‘Auto-zero” triggered by Start-in function;9. Hand-held touchscreen form-factor which facilitates mounting on side of a HPLC system and does not take up valuable laboratory bench space.10. Space-saving diverter valve assembly - in the present invention, the valve mounting hardware is separate from the hand-held controller so as to not utilise bench space, plus promote a more user friendly operation of the system of the present invention;11. The system and apparatus of the present invention is adapted to handle analog input signals up to ±2volts (this allows it to connect with all HPLC manufacturers systems on the market)In at least one embodiment, the valve means is switched to channel the solvent output for recycling or disposal, depending upon whether the detected signal shows the output solvent to be contaminated. The solvent contamination is identified by a peak in the mobile phase.In at least one embodiment, the input receives the signal from the detector over a time interval.In at least one embodiment, the components are detectable at different points during the time interval.In at least one embodiment, the electrical signal comprise a peak. In at least one embodiment, the electrical signal is a voltage.In at least one embodiment, the control system detects a signal slope / rate of change value to control the sensitivity of detection around the peak and to determine when the valve should be switched from sending the solvent that is output from the HPLC system, for recycling to the mobile phase vessel or for waste disposal.In at least one embodiment, the control system comprises a peak detection algorithm.In at least one embodiment, the peak detection algorithm handles detector outputs over a range of values for system compatibility with different HPLC detectors.In at least one embodiment, the detector output range is ±2volt.In at least one embodiment, detector output peak detection can be adjusted for custom recycle sensitivity.In at least one embodiment, detector output peak detection can be adjusted for custom recycled solvent purity.In at least one embodiment, the signal has an auto-zero function based on start input.In at least one embodiment, the computer-controlled valve has a user interface. In at least one embodiment, the user interface is a GUI.In at least one embodiment, the control system has a handheld, touchscreen form-factor for easy mounting on side or front of any HPLC manufacturers system to facilitate mounting on any manufacturer’s brand of HPLC apparatus.In at least one embodiment, the control system has a handheld, touchscreen form-factor configured to be connected to a housing of a known HPLC apparatus containing valve and HPLC electrical connections for convenient mounting on side or rear of any HPLC system.Advantageously, this negates any requirement for valuable laboratory bench space. In addition, it keeps all electrical signal cables plus valve fluid connections out of HPLC operators working area.In at least one embodiment a valve delay time is calculated from a flow-rate value of the HPLC method.In at least one embodiment, the time for which the valve is switched to send solvent to waste is controlled and optimised, so as to prevent any contaminated mobile phase being returned to mobile phase reservoir / vessel / container. Thus, the system is configured to automatically provide a margin of error to prevent waste from inadvertently being returned to a solvent vessel.In at least one embodiment, the valve is mounted on the rear of the H PLC apparatus .In at least one embodiment, a electrical terminal block is mounted on the rear housing of the HPLC apparatus.Advantageously, the valve and / or terminal block are mounted and in a way that is suitable for integration with many HPLC system models.In at least one embodiment, the computer-controlled valve records all recycle and waste events.In at least one embodiment, the computer- controlled valve records all previous injections.In at least one embodiment, the computer-controlled valve records each injection separately.In at least one embodiment, the computer controlled valve system requires individual user login with a passwordIn at least one embodiment, the computer controlled valve system produced a time and date stamped audit trail of all instrument events.In at least one embodiment, the computer controlled valve system provides a communication link and software to download audit trail reports selectable by start and end time.In at least one embodiment, the computer controlled valve system provides a communication link and software to download individual injection reports.In at least one embodiment, the computer-controlled valve system provides a communication link and software to download summary reports of total Waste and Recycle volumes of injections over a customisable time period (weekly / monthly etc.). This commentIn at least one embodiment, the recyclable output solvent is recycled to a reservoir. It is to be understood that the reservoir may comprise a container or vessel. References to a container or vessel are to be understood as referring to the reservoir.In at least one embodiment, the reservoir is a mobile phase reservoir.In accordance with the second aspect of the invention, there is provided a system for high performance liquid chromatography (HPLC), the system as recited in the appended claims.In accordance with a third aspect of the invention there is provided a method of recycling solvent from a HPLC system, the method as recited in the appended claims.In at least one embodiment, the valve is switched to channel the solvent output for recycling or disposal, depending upon whether the detected signal shows the output solvent to be contaminated.In at least one embodiment, the input receives the signal from the detector over a time interval.In at least one embodiment, component peaks are detectable at different points during the time interval.In at least one embodiment, the valve control system detects an electrical signal which identifies a separated component from the chromatography column.In at last one embodiment, the electrical signal comprises a peak on a chromatogram.In at least one embodiment, the electrical signal is a voltage.In at least one embodiment, the control system detects a signal to a threshold value to control the sensitivity of detection around the peak and to determine when the valve should be switched from sending the output solvent for recycling or waste.In at least one embodiment, the control system comprises a peak detection algorithm.In at least one embodiment, the peak detection algorithm handles detector outputs over a range of values for system compatibility with different b ra n d s o f HPLC systems.In at least one embodiment, the range is ±2volt.In at least one embodiment, detector signal processing can be adjusted for custom recycle sensitivity.In at least one embodiment, the signal has a baseline auto-zero based on a start input from the sample injector.In at least one embodiment a valve delay time is calculated from a flow rate value setting equivalent to the HPLC apparatus.In at least one embodiment the waste time interval is extended for a duration equivalent to half the time of the detected peak. This provides an additional margin of error to ensure only ultra-pure mobile phase is being returned to the solvent vessel.In at least one embodiment, the computer controlled valve records recycle and waste events.In at least one embodiment, the computer controlled valve records previous injections.In at least one embodiment, the computer controlled valve records each injection separately.In at least one embodiment, the recyclable output solvent is recycled to a reservoirIn at least one embodiment, the reservoir is a mobile phase reservoir.Peak Detection AlgorithmThe peak detection algorithm of the system of the present invention provides a signalprocessing method configured to distinguish meaningful electrical events from background noise. The system of the present invention operates using a two-tier verification process, namely, Initial Detection (via slope and width) and Sustained Event Verification (the "Dynamic Threshold" logic). The advantage of Dynamic Threshold is to identify the potential occurrence of flat-topped peaks and ensure these remain diverted to Waste even when slope and width conditions are no longer met.1. Primary Detection ParametersTo ensure accuracy, the algorithm is configured to firstly, evaluate the incoming voltage signal against two core parameters:• Slope (dV / dt): Measures the rate of voltage change over a time period.This defines the start of a peak when exceeded (and corresponding peak end when the rate of change drops below the slope setting ).This allows the system to distinguish between a sharp, meaningful peak or a slow, drifting baseline.• Width: Defines the minimum sequential duration required for a peak by averaging samples within a specified time-frame window. When combined with Slope, this parameter helps filter out high-frequency spikes or noise that lack the characteristic duration of a true peak event.Slope and Width settings can be user-programmed to determine sensitivity of peak detection and therefore the performance in eliminating component peaks from the mobile phase solvent to be recycled. Both Slope and Width settings may be adjusted based on the expected height, sharpness and width of peaks of the HPLC analysis being performed.2. Simple detection with Slope and Width (for example, Peak 1 as shown in Fig 11a) Phase 1: Signal Sampling and "Width" ProcessingTo ensure that the algorithm does not detect momentary electrical noise as peaks, the algorithm is configured to use a Width parameter to define the "time window" of observation for calculating the slope.The Width parameter determines the degree of data aggregation over which slope is calculated:o The system samples data at 50Hz (every 20ms).o Instead of comparing single raw data points (which are noisy), the algorithm uses a "Width" parameter to create averaged time windows.o The slope is calculated as the difference between these two averages ($Avg_2 - Avg_1$), not the raw points.o Fig 10 illustrates a Width of 6 data points (buffer size) in each time window.Algorithm utilises two of these time window segments to calculate two averaged Slope values termed "value_1" ($Avg 1) and "value_2." ($Avg 1) o In this example, a calculated Slope = 500 does not exceed the Slope setting of 2000, therefore No peak event is activated.o When combined with Slope, the Width parameter helps filter out high- frequency spikes or noise that lack the characteristic duration of a true peak event.Note: Higher Width values act as a low-pass filter, smoothing the signal to ensure that only sustained rises are considered.Phase 2: Event Termination (The Exit Logic)The algorithm applies the same criteria to ending a peak event as it does to peak start. This prevents the device from "flickering" between active and inactive states during a noisy decay (aka peak tailing).• The Termination Criteria: Peak termination only occurs if there are two consecutive windows not meeting the slope criteria.• Point B Transition: Once these two failures occur, the system marks Point B, closes the event data, and resets the logic to begin looking for the next slope-based trigger.3. The "Flat Top" Challenge and the Continuity Logic ((for example, Peak 2 as shown in Fig 11a)Standard peak detection often fails when a signal includes a "plateau." When the slope (i.e. rate of change) drops to zero at the top of a peak, traditional algorithms can detect that the electrical event has ended, thereby leading to premature termination of the detected peak and therefore, giving a false detection reading.The algorithm of the system of the present invention addresses this technical problem by being configured to comprise a “Dynamic Threshold” or Hysteresis-based Continuity:Phase 1: The Entry Point (Point C of Peak 2 as shown in Figure 11a)When the initial parameter conditions of Slope and Width are met, the algorithm is configured to detect and mark Point C and to store the current voltage value at Point C.Phase 2: The Continuity Zone (The "Flat Top" on the detected peak as in Peak 2 of Figure 11a)Once the signal exceeds voltage at Point C, the algorithm is configured to change its logic and to adopt status; “Active Detection”:• Status: "Active Detection."• Condition: As long as the signal remains higher in absolute value than the stored reference voltage at Point C, the algorithm treats this as continuation of the same peak, regardless of whether the slope is zero or even fluctuating slightly.• Benefit: This prevents a peak "Flat Top or Plateau" being considered as a peak end due to voltage no longer changing (i.e. lack of slope).Phase 3: The Exit Point (Point D of Peak 2 shown in Figure 11a)The system of the present invention is configured to detect and record a peak as "ended" only when the following conditions are met:I. the voltage drops back below the stored voltage reference Point D andII. Slope / Width conditions are met.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:

[0010] Figure 1 is a schematic diagram of a known HPLC system;

[0011] Figure 2 is a graphical representation, referred to as a chromatogram which shows peaks detected that indicate the presence of certain components using a known HPLC system;

[0012] Figure 3 is a schematic diagram of a first embodiment of an apparatus used with an HPLC system in accordance with the present invention;

[0013] Figure 3a is a schematic diagram of the first embodiment of an apparatus used with an HPLC system in accordance with the present invention displaying sources of tubing void volume;

[0014] Figure 4 is a chromatogram which shows an example of peak sensing as used to divert flow of solvent for recycling in accordance with the present invention;

[0015] Figure 5 is a table which shows the timing of peak detection in a first example and in accordance with the present invention;

[0016] Figure 6 is a graph which shows another example of peak sensing as used to divert flow of solvent for recycling in accordance with the present invention;

[0017] Figure 7 is an example report of a use of the device described in the current application;

[0018] Figure 7a is a chromatogram related to the Table of Figure 7; Figure 7a shows another example of peak sensing as used to divert flow of solvent for recycling in accordance with the present invention; and which shows the correlation of a peak detection of a contaminant in the solvent and the system configured for the valve to be positioned in the RECYCLE position or in the WASTE solvent position;

[0019] Figure 8 is a schematic diagram that demonstrates how peak detection sensitivity is adjustably within the algorithm by changing slope and width settings;

[0020] Figure 10 is a schematic diagram showing an example of how the intelligent peak detection of slope is calculated in accordance with the present invention;

[0021] Figure 11 is a schematic diagram showing the Dynamic Threshold feature of the present invention;

[0022] Figure 11 a is a further schematic diagram, similar to Figure 11 , and also shows in more detail, the dynamic threshold feature of the system of the present invention;

[0023] Figure 12 is a flow chart of the operation of an embodiment of the apparatus if using peak detection without Dynamic Threshold feature; and

[0024] Figure 13 is a flow chart of the operation of an embodiment of the apparatus when using peak detection with the Dynamic Threshold feature.DETAILED DESCRIPTION

[0025] In one aspect, the present invention provides an apparatus for recycling solvent in a HPLC system. In another aspect, the present invention also provides a method for use of the apparatus for recycling solvent configured for use with a high performance liquid chromatography (HPLC) apparatus.

[0026] In at least one example, the invention is a mobile phase conservation / recycling apparatus, system and method configured for dedicated to recycling pure mobile phase i.e. uncontaminated solvents used in isocratic High Performance Liquid Chromatography (HPLC) systems. In particular, the apparatus of the present invention is configured to be connected to a detector in a HPLC apparatus, the detector being configured for monitoring the contaminants of the mobile phase emerging from the chromatography column and connected to an auto-injector to synchronise time / date stamped audit trails, delay time function and auto-zero activation..

[0027] In use, the HPLC detector signal is monitored by the present invention and the solvent output from the detector is connected to a 2-way waste / recycle valve. The valve is movable between a first position in which the valve is set to a “RECYCLE position”, in whichthe solvent is recycled i.e. used again in the HPLC system as the HPLC mobile phase; and a second position in which the valve is set to a “WASTE solvent position”. In this example, the valve is set to the “RECYCLE position” which is preferably configured as a default position for operation of the valve whereby the solvent is recycled unless there is a trigger event to change the valve from the “RECYCLE position”. For example, such a trigger event occurs when the detector detects a peak indicating the presence of a component of the compound being analysed, this indicates that the solvent is contaminated and the system of the present invention switches the valve and diverts that portion of the solvent to a waste liquid vessel

[0028] Figure 3 is a schematic diagram of a first embodiment of an apparatus used with an HPLC system in accordance with the present invention. The system 31 comprises a vessel 33 which contains the pure mobile phase which is drawn from the vessel 33 by a pump 39 via an inlet tubing 35. The pure mobile phase liquid from the vessel 33 is combined with the sample 41 and passed into column 43 to undergo chromatography separation. Detector 47 detects the components and outputs this information as peaks on a graph over a time interval. The detector signal is monitored by the present invention 49.

[0029] The invention 49 analyses the detector signal for peaks and diverts the parts of the solvent flow which are contaminated by the components of the liquid sample 41. Those parts are sent to a waste output 53 by a valve in the system of the present invention.

[0030] When uncontaminated solvent is detected, the valve is operated to return the solvent to the vessel / reservoir 33 via solvent inlet 37.

[0031] The controller also has a graphical user interface which displays information on the process and allows the user to input various parameters which may be set to control peak detection sensitivity, control of the valve, and therefore purity of recycled mobile phase. For example, each injection is displayed live on the 4” touchscreen and stored within the invention internal memory

[0032] The software used in the present invention provides an Audit Trail which contains time and date stamps for all recycle and waste events. All previous events including settings changes and use of the system is recorded within the Audit Trail. E a c h injection is recorded separately.

[0033] Figure 3a shows “void” volume that is present in the tubing between the HPLC detector flow cell and the 2-way valve. This manifests in a delay time between what is observed on the HPLC system detector and when the system needs to switch the valve from RECYCLE or WASTE position. This delay time is a function of:i. Tubing Lengthii. Tubing Internal Diameteriii. Mobile Phase flow rate

[0034] The apparatus of the present application automatically calculates this Delay time following operator input of the HPLC flow rate. A sample report is shown in Figure 7.

[0035] Figure 4 is a graph (chromatogram) which shows an example of peak sensing as used to divert flow in accordance with the present invention. The graph 61 shows an X axis which graphs the time interval 63 over which the HPLC reaction is occurring for a sample of a common painkiller containing paracetamol (Acetaminophen 65, caffeine 67 and Benzoic acid 69. The controller of the present invention senses the position of the peaks for Acetaminophen 71, Caffeine 73 and Benzoic acid 75 and uses the detected signal to control the valve such that the contaminated solvent which is present during the time intervals where the peak is present in the detector output, is sent to a waste vessel.

[0036] Figure 5 is a table 81 which shows the timing of a valve Waste event based on peak detection in accordance with the present invention. Each peak has a row in the table under the event heading 83. The table shows the time interval form the start to the end of peak detection 85. The volume of contaminated solvent can be calculated from the time interval and flow rate.

[0037] In this example, there are 3 peaks which are present in a time interval of 2.49mins which amounts to 3.74mls of contaminated solvent. Therefore, the remaining 26.27mls (87.55%) of pure mobile phase which would previously have gone to waste is now being recycled using the present invention.

[0038] Figure 6 is a graph 111 which shows another example of peak sensing as used to divert flow in accordance with the present invention. It plots voltage 113 Vs time and shows peaks 117. The graph 111 also shows other parameters which are calculated in order to assist in determining when to switch the valve from sending solvent to recycle or waste vessels. These are flow rate 119, the slope setting for peak detection 121 , peak width 123 and time delay 125.

[0039] In addition, examples of the invention have many software features to make the system fit for purpose to use within highly regulated industries such as Pharmaceutical, BioTechnology and Medical Devices.

[0040] The peak detection algorithm may handle ±2 volt (analog) inputs from the HPLC detector. This range makes the invention capable of operating with all HPLC detectors on the market. The detector signal may also have a signal “Auto-Zero” based on the auto-injector 7 start output. The detector signal peak detection can be adjusted for custom recycle sensitivity including, proprietary valve “delay time” calculated from HPLC flow rate. A handheld, touchscreen form-factor may be provided for easy mounting on side of any manufacturer HPLC system (this also negates any requirement for the invention to be positioned on valuable laboratory bench space).

[0041] A rear mounted valve and electrical connection terminals are provided for flexible mounting options and integration to all manufacturers HPLC system models.

[0042] Figure 7 shows a table displaying the time in minutes in which the flow from the HPLC machine was diverted to the waste container. The report also shows the HPLC system parameters including flow rate, and informs the operator of the total volume of solvent sent to Waste and the total volume of solvent that was Recycled.

[0043] Figure 8 shows the correlation of a peak detection of contaminants in the solvent and the system configured for the valve to be positioned in the RECYCLE position or in the WASTE solvent position. There is a period of time between the end of the peak signal and switching the valve from WASTE position to RECYCLE position. This time lag ensures that no trace contaminants are erroneously recycled. This waste position hold time is calculated automatically and is an additional half the length of time that peak was detected

[0044] As shown in Figure 9, the peak detection parameters of Slope and data Width (buffer size), allow the present invention to adapt its detection criteria according to the specific chromatographic conditions, analyte properties and baseline noise levels in order to assist in distinguishing between genuine peaks and baseline fluctuations, mitigating false positives and ensuring that only significant peaks, corresponding to actual analyte presence, trigger valve activation of the valve to the WASTE position so that the solvent is sent to WASTE disposal.

[0045] Figure 10 demonstrates that following the detection of a peak, the present invention automatically enters WASTE mode to dispose of contamination associated with the peaks. To ensure complete elimination of the contents associated with that peak, the algorithm controls that the system remains in WASTE disposal i.e. that the valve remains in the WASTE disposal position for a duration equivalent to half the time of the detected peak. In this example, for instance, if a peak persists for 10 seconds, the recycler will continue WASTE disposal for an additional 5 seconds post-peak detection;

[0046] Figure 11 demonstrates that the system of the present invention is particularly effective in handling peak plateaus, a common challenge in chromatographic analysis, where stable but elevated baseline signals may otherwise be misinterpreted as a “peak end” occurrence. This effectiveness is achieved using the Dynamic Threshold feature of the present invention.

[0047] Referring now to Figure 11a, the system will be described in further detail:

[0048] Peak Detection Algorithm

[0049] The peak detection algorithm of the system of the present invention provides a signal-processing method configured to distinguish meaningful electrical events from background noise. The system of the present invention operates using a two-tier verification process, namely, Initial Detection (via slope and width) and Sustained Event Verification (the "Dynamic Threshold" logic). The advantage of Dynamic Threshold is to identify the potential occurrence of flat-topped peaks and ensure these remain diverted to Waste even when slope and width conditions are no longer met.

[0050] 1. Primary Detection Parameters

[0051] To ensure accuracy, the algorithm is configured to firstly, evaluate the incoming voltage signal against two core parameters:

[0052] Slope (dV / dt): Measures the rate of voltage change over a time period.This defines the start of a peak when exceeded (and corresponding peak end when the rate of change drops below the slope setting ).

[0053] This allows the system to distinguish between a sharp, meaningful peak or a slow, drifting baseline.

[0054] Width: Defines the minimum sequential duration required for a peak by averaging samples within a specified time-frame window.When combined with Slope, this parameter helps filter out high-frequency spikes or noise that lack the characteristic duration of a true peak event.

[0055] Slope and Width settings can be user-programmed to determine sensitivity of peak detection and therefore the performance in eliminating component peaks from the mobile phase solvent to be recycled.Both Slope and Width settings may be adjusted based on the expected height, sharpness and width of peaks of the HPLC analysis being performed.

[0056] 2. Simple detection with Slope and Width (for example, Peak 1 as shown in Fig 11a)

[0057] Phase 1: Signal Sampling and "Width" Processing

[0058] To ensure that the algorithm does not detect momentary electrical noise as peaks, the algorithm is configured to use a Width parameter to define the "time window" of observation for calculating the slope.

[0059] The Width parameter determines the degree of data aggregation over which slope is calculated:

[0060] The system samples data at 50Hz (every 20ms).

[0061] Instead of comparing single raw data points (which are noisy), the algorithm uses a "Width" parameter to create averaged time windows.

[0062] The slope is calculated as the difference between these two averages ($Avg_2 -Avg_1$), not the raw points.

[0063] Note: Higher Width values act as a low-pass filter, smoothing the signal to ensure that only sustained rises are considered.

[0064] Phase 2: Event Termination (The Exit Logic)

[0065] The algorithm applies the same criteria to ending a peak event as it does to peak start. This prevents the device from "flickering" between active and inactive states during a noisy decay (aka peak tailing).

[0066] The Termination Criteria: Peak termination only occurs if there are two consecutive windows not meeting the slope criteria.

[0067] Point B Transition: Once these two failures occur, the system marks Point B, closes the event data, and resets the logic to begin looking for the next slope-based trigger.

[0068] 3. The "Flat Top" Challenge and the Continuity Logic ((Referring to, Peak 2 as shown in Fig 11a)

[0069] Standard peak detection often fails when a signal includes a "plateau." When the slope (i.e. rate of change) drops to zero at the top of a peak, traditional algorithms can detect that the electrical event has ended, thereby leading to premature termination of the detected peak and therefore, giving a false detection reading.

[0070] The algorithm of the system of the present invention addresses this technical problem by being configured to comprise a “Dynamic Threshold” or Hysteresis-based Continuity:

[0071] Phase 1: The Entry Point (Point C of Peak 2 as shown in Figure 11a)

[0072] When the initial parameter conditions of Slope and Width are met, the algorithm is configured to detect and mark Point C and to store the current voltage value at Point C.

[0073]

[0074] Phase 2: The Continuity Zone (The "Flat Top" on the detected peak as in Peak 2 of Figure 11a)

[0075] Once the signal exceeds voltage at Point C, the algorithm is configured to change its logic and to adopt status; “Active Detection”:

[0076] Status: "Active Detection."

[0077] Condition: As long as the signal remains higher in absolute value than the stored reference voltage at Point C, the algorithm treats this as continuation of the same peak, regardless of whether the slope is zero or even fluctuating slightly.

[0078] Benefit: This prevents a peak "Flat Top or Plateau" being considered as a peak end due to voltage no longer changing (i.e. lack of slope).

[0079] Phase 3: The Exit Point (Point D of Peak 2 shown in Figure 11a)

[0080] The system of the present invention is configured to detect and record a peak as "ended" only when the following conditions are met:

[0081] the voltage drops back below the stored voltage reference Point D and

[0082] Slope / Width conditions are met.

[0083] Figure 12 shows a simple method of peak detection of one embodiment of the system. A peak is detected when a signal rate change is greater than the slope setting, and a peak is considered to have ended when a signal rate change is less than the slope setting. When a peak is detected the apparatus will switch the valve to the WASTE disposal position. When the peak ends, the valve will swap away from the WASTE disposal position to the RECYLE position. In the instance where no changes in the signal are identified the system continues operating in normal Recycle mode.

[0084] Figure 13 shows the method of operation of an alternative embodiment of the system comprising the Dynamic Threshold feature. The Dynamic Threshold feature is designed to improve accuracy and adaptability in determining genuine peaks amid noise and fluctuating baselines. This mechanism dynamically adjusts detection sensitivity by using a dualthreshold system comprising an optional manual Peak Detection Threshold and a variable Dynamic Threshold. This approach minimises errors in peak detection and refines solventdiversion, optimising both signal processing and mobile phase conservation. The invention may operate in Manual and Dynamic Threshold modes. The manual Peak Detection Threshold is a predefined voltage level setting that a signal must exceed to qualify as a potential peak. When a signal reaches or surpasses this threshold, it is immediately classified as a peak, prompting the system to switch the valve to WASTE position. However, to accommodate a range of signal characteristics, the algorithm also includes a Dynamic Threshold that can activate under certain conditions, especially when handling peak plateaus or noisy baselines that may resemble peaks. Dynamic Threshold ensures a peak will never be considered to have ended until the signal voltage decreases below the voltage at which the peak start was triggered.

[0085] Advantageously, the present invention has the following monetary and environmental advantages.1. Reduces the mobile phase waste by 80-92%.2. Less Solvent Usage costs.3. Less Mobile Phase Preparation Time costs.4. Less Waste Disposal costs.5. Less exposure of personnel to harmful chemicals.6. Less Shipping costs.7. Less Mobile Phase / Solvent use requires less energy to produce.8. Less Shipping Pollution.9. Less Disposal Pollution.10. Better use of Resources.11. Less Solvent Usage = Less Preparation Time.12. Less Purchasing Admin and incoming solvent verification.13. Less Warehouse space allocation requirement14. Less Administration Time for environmental waste licensing and Disposal.15. The Dynamic Threshold feature also extends the algorithm's adaptability to variable sample compositions and chromatographic conditions, ensuring accuracy in diverse analytical settings. This mechanism enhances the system's precision in interpreting chromatographic data by fine-tuning sensitivity based on real-time data trends, improving overall reliability and reducing solvent waste due to erroneous peak detection. Specifically, using Dynamic Threshold, the system is able to identify peaks with low rates of signal change that may otherwise be erroneously identified as baseline. This prevents accidental contamination of the recycling solvent loop.

[0086] The embodiments of the present invention described with reference to the drawings comprise a computer apparatus and / or processes performed in a computer apparatus.However, the invention also extends to computer programs, particularly computer programs stored on or in a carrier adapted to bring the invention into practice. The program may be in the form of source code, object code, or a code intermediate source and object code, such as in partially compiled form or in any other form suitable for use in the implementation of the method according to the invention. The carrier may comprise a storage medium such as ROM, e.g. a memory stick or hard disk. The carrier may be an electrical or optical signal which may be transmitted via an electrical or an optical cable or by radio or other means.

[0087] In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

[0088] The invention is not limited to the embodiments herein before described but may be varied in both construction and detail.

[0089] Throughout the description and claims ofthis specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0090] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0091] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMS1.A computer-controlled system for use with a high performance liquid chromatography (HPLC) system having a chromatography column, wherein the computer-controlled valve system is adapted to be connected to a detector for detecting the components of the solvent emerging from the chromatography column, the computer controlled system comprising:a valve means configured to receive an output solvent from the HPLC system; the valve means being moveable between a RECYCLE position in which the solvent is directed to be recycled for re-use in the HPLC system and a WASTE position in which the solvent is directed to be sent for waste disposal;a control system operatively, in use, connected to the detector and to the valve means for controlling the operation of the valve means between the RECYCLE position and the WASTE position such that the detected input signal determines whether the valve means diverts the output solvent for recycling or waste disposal; the control system comprising:■ a Peak Detection Algorithm, wherein the algorithm is configured to:■ analyze the rate of change of the chromatographic signal that calculates a slope value based on two averaged signal segments;■ compare the slope value to a pre-set Peak Detection Slope threshold to identify a peak event;■ activate the valve to direct the solvent to the waste stream during a peak event; and■ maintain the solvent in the recycling stream when no peak is detected; andwherein the control system further comprises a Dynamic Threshold Mechanism, wherein the dynamic threshold mechanism is adapted to dynamically adjusts peak detection sensitivity based on real-time chromatographic data trends.

2. A computer-controlled valve system for a high-performance liquid chromatography (HPLC) system as claimed in claim 1, wherein the detector is also configured to monitor chromatographic signals generated during the separation of analytes in a solvent stream.

3. The valve system of claim 1 or claim 2 further comprising an adjustable parameter module that allows customization of slope sensitivity, data width (buffer size), and threshold values to accommodate specific chromatographic conditions, analyte properties, and baseline noise levels.

4. The system of any preceding claim, wherein the computer-controlled system is configured to be connected to an auto-injector to synchronise time / date stamped audit trails, delay time function and auto-zero activation.

5. The system of any preceding claim wherein the system comprises a manual Peak Detection Threshold.

6. The system of any preceding claim wherein the system comprises a variable Dynamic Threshold that adjusts sensitivity to account for fluctuating baselines or peak plateaus and is configured to ensure that the system remains in waste mode until the signal drops below the threshold recorded at the start of the peak.

7. The system of claim 1 or 2, wherein the Peak Detection Algorithm is configured to maintains the system in waste mode for a duration equivalent to half the time of the detected peak after the peak event ends, to ensure complete disposal of residual solvents associated with the peak.

8. The system of claim 1 , wherein the Peak Detection Algorithm includes a noisemitigation mechanism to distinguish genuine analyte peaks from baseline fluctuations or noise.

9. The system of claim 1 , wherein the detector is configured to operate with variable sample compositions and chromatographic conditions, ensuring high adaptability of the peak detection process.

10. The system of claim 1 , wherein the control system is configured to log peak events and solvent channelling data for quality control and traceability purposes.

11. The system of claim 1 , wherein the circular buffer used in the Peak Detection Algorithm is configurable to optimize data processing speed and memory usage.

12. The system of claim 1 , wherein the system improves environmental sustainability by reducing solvent waste and optimizing solvent recycling efficiency.

13. A method for recycling solvent in a high-performance liquid chromatography (HPLC) system, comprising:o detecting chromatographic signals from a mixture of analytes and solvent as the analytes are separated by a chromatography column;o analyzing the detected chromatographic signals using a Peak Detection Algorithm, the algorithm comprising:■ monitoring the rate of change of the chromatographic signal using a circular buffer that calculates a slope value based on two averaged segments;■ identifying a peak event when the slope value exceeds a predefined Peak Detection Slope threshold; and■ maintaining the system in recycle mode when the slope value is below the threshold;o channelling the output solvent to a recycling stream during non-peak events;ando channelling the output solvent to a waste stream during peak events whereby the valve is switched to direct the solvent output for recycling or disposal, depending upon whether the detected signal shows the output solvent to be contaminated; ando wherein the control system further comprises a Dynamic Threshold Mechanism, wherein the dynamic threshold mechanism is adapted to dynamically adjusts peak detection sensitivity based on real-time chromatographic data trends.

14. The method of claim 13, wherein the Peak Detection Algorithm includes adjustable parameters, allowing the user to modify slope sensitivity, buffer size, and detection thresholds based on specific chromatographic conditions.

15. The method of claim 13 or 14, further comprising:maintaining the system in waste mode for a duration equivalent to half the time of the detected peak after the peak event ends, ensuring complete elimination of residual solvents associated with the analyte.

16. The method of any preceding claim wherein the method also comprises the step of dynamically adjusting the detection sensitivity using a Dynamic Threshold Mechanism, wherein the mechanism prevents false positives by maintaining the system in waste mode until the signal level drops below the threshold recorded at the start of the peak; and accounting for fluctuating baselines and plateaus in chromatographic signals.

17. The method of claim 16, wherein the Dynamic Threshold Mechanism is configured to dynamically adjusts sensitivity for improved signal differentiation between genuine peaks and noise; and thereby optimize solvent use and reduces waste by minimizing erroneous peak detection.

18. The system as claimed in any of claims 1 -12 wherein, the control system detects an electrical signal which identifies a separated component from the chromatography column.

19. The system as claimed in claim 18 wherein, the electrical signal comprises a peak.

20. The system as claimed in claim 18 or claim 19 wherein, the electrical signal is a voltage.

21. The system as claimed in any preceding claim wherein, the control system detects a signal to a slope / rate of change value to control the sensitivity of detection around the peak and to determine when the valve means should be switched from sending the output solvent for recycling or waste.

22. The system as claimed in claim 19 wherein, the peak detection algorithm handles detector inputs over a range of values for system compatibility with different HPLC detectors.

23. The system as claimed in claim 22 wherein, the detector output range is ±2 volts.

24. The system as claimed in any of claims 1-12 wherein detector output peak detection can be adjusted for custom recycle sensitivity.

25. The system as claimed in claim 24 wherein detector output peak detection can be adjusted for custom recycled solvent purity.

26. The system as claimed in any of claims 1-12 wherein the signal has an auto-zero function based on start input from auto-injector.

27. The system as claimed in any of claims 1-12 wherein the computer controlled valve has a user interface.

28. The system as claimed in claim 27 wherein, the user interface is a graphical user interface (GUI).

29. The system as claimed in any of claims 1-12 wherein, the control system has a handheld, touchscreen form-factor for ease of connecting to or mounting on any HPLC manufacturer’s system.

30. The system as claimed in claim 29 further comprising connected rear mounted enclosure containing valve means and electrical connections for ease of connecting the system to or mounting on any HPLC manufacturers system.

31. The system as claimed in any of claims 1-12 wherein a valve delay time is calculated from a flow rate value of the HPLC method.

32. The system as claimed in any of claims 1-12 wherein, a waste time interval may be set by a user which provides a margin of error to prevent waste from inadvertently being returned to a solvent vessel.

33. The system as claimed in any of claims 1-12 wherein the computer controlled valve records recycle and waste events.

34. The system as claimed in any of claims 1-12 wherein, the computer controlled valve system requires individual user login with a password.

35. The system as claimed in any of claims 1-12 wherein the computer controlled valve system produced a time and date stamped audit trail of all instrument events.

36. The system as claimed in any of claims 1-12 wherein, the computer controlled valve system provides a communication link and software to download audit trail reports selectable by start and end time.

37. The system as claimed in any of claims 1-12 wherein the computer controlled valve system provides a communication link and software to download individual injection reports.

38. The system as claimed in any of claims 1-12 wherein the computer controlled valve records previous injections.

39. The system as claimed in any of claims 1-12 wherein the computer controlled valve records each injection separately.

40. The system as claimed in any of claims 1-12 wherein the valve means is in fluid comm unication with the chromatography colu mn of the HPLC and the recyclable output solvent is recycled to a reservoir.

41. A system for high performance liquid chromatography (HPLC), the system comprising:a sample comprising one or more components; a mixture of the sample and the solvent which is created prior to the introduction of the solvent into the chromatography column;a detector for detecting the presence of each of the one or more component in the mixture as it is separated from the solvent; anda computer controlled system as claimed in claims 1 to 12 and 18-41.

42. The method as claimed in any of claims 13 to 17 wherein the control system detects a signal to a threshold value to control the sensitivity of detection around the peak and to determine when the valve should be switched from sending the output solvent for recycling or disposal.

43. The method as claimed in any of claims 13 to 17 wherein, the peak detection algorithm handles detector outputs over a range of values for system compatibility with different HPLC detectors.

44. The method as claimed in claim 45 wherein, the range is ±2 volts.

45. The method as claimed in any of claims 13 to 17 wherein the detector signal sensitivity can be adjusted for custom recycle sensitivity.

46. The method as claimed in any of claims 13 to 17 wherein the signal has an autozero function based on a start input.

47. The method as claimed in any of claims 13 to 17 wherein a valve delay time is calculated from a flow rate value for the separation undergone using the HPLC apparatus.

48. The method as claimed in any of claims 13 to 17 wherein, a waste time interval may be set by a user which provides a margin of error to prevent waste from inadvertently being returned to a solvent vessel.

49. The method as claimed in any of claims 13 to 17 wherein the computer controlled valve is configured to record recycle and waste events.

50. The method as claimed in any of claims 13 to 17 wherein the computer controlled valve is configured to record previous injections.

51. The method as claimed in any of claims 13 to 17wherein the computer controlled valve records each injection separately.

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