Gas chromatograph and gas chromatograph system having hydrogen generating condensate

Abstract

The present invention relates to a gas chromatograph system 1000 for detecting volatile organic compounds in an analyte 320, using a gas chromatograph 100 having an injector for injecting the analyte 320, a preconcentrator 120, a column 140 with a stationary phase 141, and a gas detector 150 for detecting components of the analyte 320 eluted from the column 140. The present invention proposes a condensate 160 having an outlet coupled to the gas chromatograph 100, for receiving and processing a hydrogen-containing medium 330 to generate hydrogen 310, and for supplying the hydrogen 310 to the gas chromatograph 100. The present invention further relates to such a condensate 160 and to a method for operating such a chromatographic system.

Description

[Technical Field]

[0001] The present invention relates to a gas chromatographic system for detecting volatile organic compounds in an analyte. Additionally, the present invention relates to a gas generator for a gas chromatographic system, and to a method of operating such a gas chromatographic system. [Background technology]

[0002] A gas chromatography system typically includes a column and a detector for separating and identifying different components in an analyte, such as volatile organic compounds. Analytes passing through a column coated with a layer used as a stationary phase are separated into components due to differences in their interactions with the stationary phase. The detector measures the amount of separated components exiting the column as a function of time. A flow of carrier gas, used as a mobile phase, is required to transport the analytes through the column. Furthermore, some detectors require combustion gas to detect the amount of separated components exiting the column. Therefore, a chromatographic system also includes a fluid source, such as a fluid container for storing the carrier gas or combustion gas. For example, as disclosed in U.S. Patent Application Publication No. 2020 / 0049673 A1, nitrogen, helium, or hydrogen can serve as the carrier gas. However, fluid containers are limited in terms of volume. Therefore, long operating times always result in an increase in system size. This is particularly disadvantageous for continuous gas chromatography, as required for distributed sensor networks used in greenhouses. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention aims to propose a concept for supplying a carrier gas that functions as the mobile phase in a gas chromatograph, which allows for long operating times without increasing the system size. [Means for solving the problem]

[0004] In a first aspect of the present invention, a gas chromatograph system for detecting volatile organic compounds in an analyte is provided. The gas chromatograph system includes a gas chromatograph having an injector for injecting an analyte into the gas chromatograph, a preconcentrator for concentrating the injected analyte, a column with a stationary phase, and a gas detector for detecting analyte components eluted from the column. The gas chromatograph system further includes a concentrator having an outlet coupled to the gas chromatograph, for receiving and processing a hydrogen-containing medium to generate hydrogen and supplying the hydrogen to the gas chromatograph via the outlet. By having the concentrator directly coupled to the gas chromatograph and adapted to process the hydrogen-containing medium to generate hydrogen, additional fluid containers and piping can be avoided. This allows for a smaller size of the gas chromatograph system, and the operating time is no longer limited by the capacity of the liquid container. In this regard, the term "processing" should be understood to mean performing chemical and / or physical reactions that affect the purity, aggregation state, or chemical composition of the hydrogen-containing medium, thereby providing a flow of hydrogen gas. The term "generate" should be understood to mean, on the one hand, generating hydrogen from a mixture containing hydrogen, and, on the other hand, recycling contaminated hydrogen by converting it into sufficiently pure hydrogen. Preferably, the gas chromatograph is a micro gas chromatograph. Micro gas chromatography is performed on a micro gas chromatograph for increased portability, reduced power consumption, and increased analytical speed. In this regard, the term "micro gas chromatograph" refers herein to a field-portable version of a gas chromatograph consisting of one or more microfabricated components. Furthermore, such an assembly provides a hydrogen flow with a sufficient velocity to carry the analyte through the column without the need for a pump to accelerate the carrier gas. However, a pump may be provided to further control the carrier gas velocity. Instead of an injector, a pump may be associated with the inlet that injects the analyte into the preconcentrator and the flow path of the carrier gas, which according to the present invention is hydrogen.

[0005] In this regard, the inventors have recognized that hydrogen provides optimal flow characteristics and improved resolution. In particular, the use of hydrogen allows for a wider flow rate range and a tighter tolerance for error compared to, for example, nitrogen, resulting in satisfactory detection results for the detector. A preferred velocity for hydrogen acting as a carrier gas that provides optimized results is approximately 40 cm / sec.

[0006] Preferably, the aggregate includes a water source and a polymer electrolyte membrane (PEM) electrolyzer for water electrolysis. In PEM water electrolysis, a cell equipped with a PEM, a thin polymer electrolyte membrane, e.g., a solid polymer electrolyte (SPE), is responsible for proton conduction, product gas separation, and electrode electrical insulation. Water provided to the anode side of the PEM electrolyzer is processed into hydrogen, which is provided to the cathode side of the PEM electrolyzer, while oxygen is provided to the anode side of the PEM electrolyzer. One of the greatest advantages of PEM electrolyzers is their ability to operate at high current densities, thereby reducing operational costs. Furthermore, the polymer electrolyte allows PEM electrolyzers to operate with very thin membranes, 100 μm to 200 μm, while still tolerating high pressures, resulting in low ohmic losses and high-compressed hydrogen output. Therefore, PEM electrolyzers are particularly useful for use in micro gas chromatographs.

[0007] It is further preferred that the aggregate have an aggregate inlet port equipped with a filter for filtering the hydrogen-containing medium.

[0008] According to a preferred embodiment, the hydrogen-containing medium is ambient air and the filter is an air filter that filters the ambient air that comes in. Thus, the condensate uses a medium that is easily accessible in the environment of the gas chromatograph system.

[0009] According to an alternative embodiment, the hydrogen-containing medium is exhaust gas from a gas chromatograph, and the filter is an exhaust gas filter that filters the incoming exhaust gas. Thus, a closed system is provided in which exhaust gas is filtered and recycled for hydrogen generation or reuse. Such an exhaust gas filter filters volatile organic compounds from the exhaust gas and preferably includes one, more, or all of a carbon-based granular sorbent, a porous polymer, a metal-organic framework, a thin film sorbent, and a foam-based sorbent. Examples of carbon-based granular sorbents commonly used for VOC filtration include highly porous activated carbon or carbon.

[0010] According to another preferred embodiment, the hydrogen-containing medium is exhaust gas from a gas chromatograph and the filter is a PEM fuel cell that filters the incoming exhaust gas. A PEM fuel cell is a fuel cell that is powered by a PEM.

[0011] Preferably, the aggregate includes a pressurized hydrogen buffer fluidly connected to the outlet to provide a flow of pressurized hydrogen. Having a pressurized hydrogen buffer increases the storage capacity of the aggregate, providing a volumetric flow rate high enough to serve as a mobile phase for carrying analytes through the column without acceleration by an additional pump. Preferably, the aggregate further includes a desiccant for drying the hydrogen in the pressurized hydrogen buffer. More preferably, the aggregate includes a heating unit associated with the desiccant for drying the desiccant for regeneration of the desiccant. More preferably, the desiccant is included in a dual-bed dryer, allowing for continuous drying of the desiccant in a first bed while simultaneously drying hydrogen with the desiccant in a second bed (or vice versa).

[0012] According to a preferred embodiment, the outlet has a nozzle that minimizes flow rate fluctuations, thus providing a more constant hydrogen flow at the outlet for supplying the hydrogen flow to the gas chromatograph.

[0013] According to an alternative preferred embodiment, the outlet has a proportional valve that controls the flow of hydrogen, thus allowing the output of the hydrogen flow to be controlled according to the actual demands of the gas chromatograph system.

[0014] Preferably, the aggregate has a pressure relief valve to vent excess pressure.

[0015] According to a preferred embodiment, the water source includes a condenser for water acquisition and a condensate buffer for water storage. The condenser includes a flow channel having a condenser surface and a cooling unit for actively cooling the condenser surface. The condenser surface may be provided with a hydrophobic coating to facilitate removal of condensed water. The condenser surface may have features to increase its surface area. The condenser generates usable water for PEM electrolysis by enabling condensation of water contained in the ambient air. The condensate buffer, where the generated condensate is stored, allows for continuous production of hydrogen from the stored condensate. Preferably, the condenser, or at least the condenser surface of the flow channel, is pyramidal. The flow channel preferably has a hydrophobic coating. Thus, the condensate can easily flow along the hydrophobic coating and collect at the lowest point of the pyramidal-shaped condenser. It should be understood that the lowest point of the pyramidal-shaped condenser is near the PEM electrolyzer when the assembly is in an upright position.

[0016] Preferably, the aggregate comprises a temperature control unit for controlling the condenser surface temperature, such a temperature control unit being preferably integrated into the central control unit or may be provided as a separate temperature control unit.

[0017] Preferably, the aggregate has one or more sensors, in particular a humidity sensor and / or a temperature sensor, to facilitate control of water condensation.

[0018] Preferably, the cooling unit includes a Peltier element, a heat sink, and an energy supply, particularly a voltage supply, coupled to the Peltier element to provide a voltage, particularly a DC voltage, such that a hot side of the Peltier element adjacent to the heat sink and an opposite cold side of the Peltier element facing the condenser surface are formed. It should be understood that the cold side of the Peltier element facing the condenser surface can either be in direct contact with the condenser surface or be thermally coupled to the condenser surface. The Peltier element enables thermoelectric cooling based on the so-called Peltier effect. The Peltier element is a solid-state active heat pump that transfers heat from one side of the device to the other while consuming electrical energy depending on the direction of current flow. Thus, the Peltier element can be used to transport heat from the cold side to the hot side, thereby cooling the ambient air flowing through the flow path. The heat sink functions to dissipate heat from the hot side of the Peltier element away from the condenser and away from the aggregate. Preferably, the cooling unit further includes a fan that provides a cooling airflow to the heat sink, thereby assisting heat transport from the aggregate. Preferably, a portion of the ambient air flowing through the flow passages is directed through the aggregates such that cooling air is provided through cooling passages along the surface of the heat sink.

[0019] Preferably, the condenser further includes a condensate port connecting the flow path with the condensate buffer to guide the condensate from the condenser surface to the condensate buffer. Thus, a flow path is defined from the flow path to the condensate buffer. Preferably, the condensate port is located at the lowest point of the flow path when the aggregates are in an upright position. Thus, the aggregates collect at the lowest point and enter the port directly to be guided to the condensate buffer. Therefore, more efficient guidance of the condensate is provided, thereby reducing condensate loss and evaporation.

[0020] It is further preferred that when the aggregate is in an upright position, the condensate buffer comprises a sump located below the condenser and above the PEM electrolyser, so that the condensate is guided into the buffer by gravity, avoiding pipes or pumps and valves.

[0021] The sump further preferably has an overflow with a water seal that allows excess condensate while preventing air from entering the sump. Additionally or alternatively, the sump preferably has a float switch that allows excess condensate while preventing air from entering the sump, or that shuts off the Peltier element, thereby halting water production. Overflow and damage to the aggregates can thus be avoided accordingly. Furthermore, evaporation of the condensate is avoided or at least reduced. The condenser further preferably has an oxygen port that allows oxygen to rise from the condensate buffer into the flow channels when the aggregates are in an upright position. Thus, the amount of oxygen in the condensate buffer is reduced. Preferably, the oxygen port is located proximal to the inlet port of the flow channels. Thus, oxygen is carried with the inflow of the hydrogen-containing medium through the flow channels and used to cool the heat sink.

[0022] Preferably, the condensate buffer has a lid with small holes to minimize evaporation of the condensate. Overpressure in the condensate buffer affects the evaporation point. Therefore, the small holes allow ambient pressure to be maintained in the condensate buffer. The small holes can include a condensate port and an oxygen port.

[0023] According to another preferred embodiment, the condenser includes several heat conductors connecting the PEM electrolyzer and the Peltier element for cooling the contact surface of the PEM electrolyzer, which at least partially defines the condenser surface. It is further preferred that a storage space is formed between the two heat conductors, the contact surface, and a thermal insulator attached to the cold side of the Peltier element. In this regard, the storage space at least partially defines the flow path and contains a condensate buffer. It is further preferred that the condensate buffer is formed by an open-cell foam and / or a desiccant, in particular silica gel or zeolite. A condensate buffer formed by an open-cell foam allows the aggregate to be used regardless of its orientation, since water is stored in the open cells of the foam. The storage space thus defined allows water to condense immediately on the surface of the PEM electrolyzer, which is cooled by the heat conductors. In this regard, the heat conductor must allow the flow of a hydrogen-containing medium, in particular ambient air, through the storage space, which includes the open-cell foam acting as a condensate buffer. Thus, the ambient air flowing through the open-cell foam is condensed on the surface of the PEM electrolyzer and converted into hydrogen, which is stored in the pressurized hydrogen buffer.

[0024] According to another embodiment, the water source comprises a water buffer, preferably comprising an open-cell foam and / or a desiccant, in particular silica gel or zeolite. As an alternative to the use of a condenser, such a water buffer allows for a consistent availability of water for electrolysis in the PEM electrolyzer. In this regard, zeolites and silica gels can store water up to a maximum saturation level. To extract water from the zeolite or silica gel, the water buffer further comprises a heating section to evaporate the water and a cooling section to cool the evaporated water below the dew point, thereby producing water for electrolysis in the PEM electrolyzer.

[0025] Preferably, the agglomerate includes a hydrogen pump that pumps filtered hydrogen from the exhaust filter into a pressurized hydrogen buffer. Thus, by filtering the incoming exhaust gas using the exhaust filter and pumping the filtered hydrogen into a pressurized hydrogen buffer, a hydrogen cycle is provided that allows hydrogen to be reused from the gas chromatograph. Instead of using the exhaust gas, hydrogen can be trapped in a hydrogen-containing medium and released by heating. The supply of hydrogen is controlled by several valves. It is further preferred that the agglomerate includes a filter heating unit associated with the exhaust filter that heats the exhaust filter for release of trapped VOCs. Preferably, the agglomerate includes at least one valve that allows removal of VOCs released from the exhaust filter.

[0026] Preferably, the water source comprises a water buffer, the aggregate comprises a PEM fuel cell that produces the water stored in the water buffer by generating electricity, particularly by a combustion process, and oxygen rising from the water buffer is stored in the oxygen buffer.

[0027] According to another preferred embodiment, the water source is an open-cell foam filled with water and positioned adjacent to the PEM electrolyzer. Because the open-cell foam is filled with water, the gas chromatograph system, particularly the aggregate, can be provided as a closed system using water contained in the open-cell foam. Such open-cell foam can be refilled as needed without the need for tubing systems or pressurized vessels, which increase the cost of the aggregate. Thus, the water-filled open-cell foam allows for handling of the aggregate, and preferably the entire gas chromatograph, regardless of orientation, providing a low-cost water source for PEM electrolysis.

[0028] Preferably, the aggregate further includes a gas diffusion layer that provides a barrier between the water buffer and the ambient air that is permeable to the outward gas flow of oxygen generated by the PEM electrolyzer, but impermeable to water. Thus, oxygen generated by PEM electrolysis can leave the aggregate, while preventing water leakage from the water buffer. More preferably, the gas diffusion layer is also impermeable to incoming gas flows other than oxygen. Thus, the ingress of any gases that may interfere with PEM electrolysis is prevented.

[0029] Preferably, the aggregate is coupled to an inlet port of a column or pre-concentrator to provide a hydrogen gas stream that carries the analytes through the column. In this manner, the hydrogen generated by the aggregate can be used to generate a steady gas stream that is considered the mobile phase that is introduced into the column. More preferably, the aggregate is coupled to an inlet port of a column to provide a hydrogen gas stream that carries the analytes through the column, and to an inlet port of a pre-concentrator to provide a hydrogen gas stream for pre-concentrating volatile organic compounds in the pre-concentrator.

[0030] Preferably, the aggregate includes a control unit having a controllable energy source for supplying a voltage or current, at least one sensor for providing a sensor signal, and a controller, in particular a PID controller, for controlling the supply of the voltage or current based on the sensor signal. Preferably, the control unit has a data interface for communication with a network for receiving network data. Preferably, the controller controls the supply of the voltage or current based on the network data.

[0031] The control unit is preferably a central control unit which includes a temperature control unit.

[0032] It is further preferred that the control unit controls hydrogen capture in the pressurized hydrogen buffer by the controller controlling the supply of voltage or current supplied by the energy source to the PEM electrolyser based on a sensor signal of the sensor, wherein the sensor is a pressure sensor detecting the pressure in the pressurized hydrogen buffer or a flow sensor detecting hydrogen flow to the pressurized hydrogen buffer.

[0033] More preferably, the control unit controls the temperature of the condenser surface by controlling the supply of voltage or current provided by the energy source to the cooling unit based on the sensor signal. Here, the sensor is a temperature sensor that detects the temperature of the condenser surface. In this regard, the temperature of the condenser surface is controlled to be lower than the dew point of the ambient air but high enough to avoid icing. More preferably, the control unit includes a temperature sensor and / or a dew point sensor that provides sensor information regarding the dew point of the ambient air.

[0034] It is further preferred that the control unit is arranged such that the controller controls the supply of voltage or current supplied by the energy source to the cooling unit based on the sensor signal, thereby controlling the amount of condensate stored in the condensate buffer. Preferably, the sensor signal is provided by a condensate level monitoring unit including one, more or all of the following sensors: a water level sensor, or a flow sensor to detect the flow of condensate into the condensate buffer, a humidity sensor to detect humidity in the environment. Preferably, the control unit further controls a float switch associated with an overflow of the condensate buffer to selectively allow the outward flow of condensate. Preferably, said float switch is a first float switch and the control unit further controls a second float switch arranged between the PEM electrolyzer and the condensate buffer to selectively interrupt the fluid connection between the PEM electrolyzer and the condensate buffer.

[0035] It is further preferred that the control unit controls hydrogen acquisition in the pressurized hydrogen buffer by the controller controlling the supply of voltage or current supplied by the energy source to the pump based on a sensor signal of the sensor, wherein the sensor is a pressure sensor that detects the pressure in the pressurized hydrogen buffer or a flow sensor that detects the hydrogen flow to the pressurized hydrogen buffer.

[0036] It is further preferred that the control unit controls the amount of water stored in the water buffer by controlling the supply of voltage or current supplied by the energy source to the fuel cell based on a sensor signal from the sensor, wherein the sensor is a pressure sensor that detects the pressure in the pressurized hydrogen buffer or a flow sensor that detects the flow of hydrogen to the pressurized hydrogen buffer.

[0037] In this way, optimized process control is possible, for example by the control unit avoiding overflow of the pressurized hydrogen buffer and the condensate buffer and optimizing the temperature control to promote condensation.

[0038] In a further preferred embodiment, the aggregate includes an idle-mode storage unit fluidly connected to the pressurized hydrogen buffer. The idle-mode storage unit includes a solid storage medium that forms a hydride upon contact with hydrogen, a pressure release valve, and a hydride storage heater that heats the solid storage medium to reform hydrogen from the formed hydride. Thus, hydrogen is chemically bound or absorbed by the metal without requiring compression of the aggregate in idle mode. Hydrogen storage in a solid storage medium is based on the principle that some solid media, particularly metals and metal alloys, can store gaseous hydrogen. In this process, hydrogen atoms, i.e., dissolved hydrogen, are deposited in so-called "interstitial sites" and the solid storage medium (e.g., metal or gas) forms a compound, resulting in a metal hydride. Heat is released during hydrogen absorption, but release requires additional heat and pressure reduction. In this regard, heat is generated by the hydride storage heater, and pressure is reduced by the pressure release valve.

[0039] Preferably, the agglomerate includes an intermediate storage unit located downstream of the agglomerate inlet port and upstream of the PEM electrolyzer, the intermediate storage unit having a desiccant bed for storing, in particular adsorbing, water from the hydrogen-containing medium, and a heating element for evaporating the water stored in the desiccant bed. This provides intermediate storage that allows moisture to be stored in areas with high ambient humidity and to reserve moisture for later hydrogen generation when needed to supply hydrogen to a gas chromatograph. Furthermore, the agglomerate can also be used in areas with low ambient humidity.

[0040] Preferably, the agglomerate is arranged upstream of the outlet in the transport direction and includes a drying unit for drying the hydrogen, which includes a desiccant, in particular an adsorbent zeolite or silica gel, for storing and absorbing moisture from the evolved hydrogen, thus further improving the accuracy of the gas chromatograph.

[0041] Preferably, the agglomerate is associated with a drying unit, which includes a drying unit for drying the desiccant for regeneration of the desiccant.

[0042] According to a preferred embodiment, the aggregate includes a Nafion dryer unit for removing moisture from the hydrogen-containing medium. The Nafion dryer unit includes a Nafion dryer for processing wet hydrogen, a purge gas for producing dry hydrogen, an air conveying unit for allowing the flow of the hydrogen-containing medium, and at least one Nafion dryer desiccant bed for drying the hydrogen-containing medium, which serves as the purge gas. Preferably, the Nafion dryer desiccant bed has an associated bed heater for heating the Nafion dryer desiccant bed to remove stored moisture. More preferably, the Nafion dryer desiccant bed is a first Nafion dryer desiccant bed, and the Nafion dryer unit further includes a second Nafion dryer desiccant bed, a first valve for selectively allowing the flow of the hydrogen-containing medium to the first Nafion dryer desiccant bed, and a third valve for selectively allowing the flow of the hydrogen-containing medium to the second Nafion dryer desiccant bed. Thus, if the first Nafion dryer desiccant bed becomes saturated, purge gas can be provided by the second Nafion dryer desiccant bed, and vice versa. Preferably, there is a first bed heater associated with the first Nafion dryer desiccant bed and a second bed heater associated with the second Nafion dryer desiccant bed. Heating each Nafion dryer desiccant bed can release stored moisture. Preferably, the first Nafion dryer desiccant bed is connected to an exhaust port and / or a condenser via a second valve, particularly a controllable valve or a check valve. Thus, moist air removed from the first Nafion dryer desiccant bed is either discharged or directed to the condenser. Thus, the second Nafion dryer desiccant bed is preferably connected to an exhaust port and / or a condenser via a fourth valve, particularly a controllable valve or a check valve. Thus, moist air removed from the second Nafion dryer desiccant bed is either discharged or directed to the condenser. Therefore, when using both a condenser with a PEM electrolyzer and a Nafion dryer unit, the efficiency of the agglomerates is further increased.

[0043] Preferably, the aggregate has an outlet for supplying hydrogen to a gas chromatograph; an injector for supplying hydrogen, which serves as a mobile phase carrying the analyte in the transport direction; a preconcentrator for providing hydrogen to serve as a mobile phase carrying the analyte in the transport direction; One, more, or all of the columns are coupled to provide hydrogen, which acts as a mobile phase carrying the preconcentrated analytes in the transport direction. In this manner, hydrogen can be used as a mobile phase to ensure safe operation of the gas chromatograph, even in applications requiring high temperature preconcentrators and columns to enable preconcentration of analytes and separation of volatile organic compounds.

[0044] Preferably, the condenser has an outlet coupled to supply hydrogen to the gas detector to supply hydrogen to the gas chromatograph, which serves as the combustion gas for the operation of the gas detector. Thus, hydrogen can be used as the combustion gas for the gas detector. For example, a suitable gas detector using hydrogen as the combustion gas is a flame ionization detector (FID). The operation of an FID is based on the detection of ions formed during the combustion of organic compounds in a hydrogen flame. The generation of these ions is proportional to the concentration of organic species in the sample gas stream.

[0045] The aggregates generate oxygen as a by-product and are coupled to a gas chromatograph. an injector for supplying oxygen, which acts as a mobile phase carrying the analyte in the transport direction; a preconcentrator for supplying oxygen to act as a mobile phase carrying the analyte in the transport direction; a column for supplying oxygen, which acts as a mobile phase carrying the preconcentrated analytes in the transport direction; or It is further preferred to provide oxygen to at least one of the preconcentrators for supplying oxygen to preconcentrate the analytes, so that oxygen can be used as the mobile phase for low temperature applications that do not require high temperature preconcentrators or columns, allowing for preconcentration of analytes and separation of volatile organic compounds, rather than introducing by-products into the environment.

[0046] In a second aspect of the present invention, an aggregate for providing a hydrogen gas flow to a gas chromatograph system, particularly a gas chromatograph system according to the first aspect of the present invention, is provided. The aggregate has an outlet coupled to the gas chromatograph, receives and processes a hydrogen-containing medium to generate hydrogen, and supplies hydrogen to the gas chromatograph. The aggregate for a gas chromatograph system also shares the advantages described above with respect to the first aspect of the present invention.

[0047] In a further aspect of the present invention there is provided a method of operating a gas chromatograph system, in particular a gas chromatograph system according to the first aspect, said method comprising: generating pressurized hydrogen to serve as a mobile phase for a gas chromatograph; providing a mobile phase at an inlet of a gas chromatograph; introducing pressurized hydrogen, which serves as a mobile phase, into the gas chromatograph, thereby accelerating the mobile phase; injecting the sample into a preconcentrator; concentrating the analyte containing volatile organic compounds in a pre-concentrator; carrying the analyte from the preconcentrator to a column containing a stationary phase in a transport direction with a mobile phase; directing the pre-concentrated analytes carried by the mobile phase through the column; and detecting volatile organic compounds eluted from the column with a gas detector.

[0048] Preferably, the step of supplying hydrogen to the gas chromatograph comprises: providing hydrogen to an injector to provide hydrogen that serves as a mobile phase carrying the analyte; providing hydrogen to a pre-concentrator to provide hydrogen that functions as a mobile phase carrying the analyte; supplying hydrogen to the column to provide hydrogen that functions as a mobile phase carrying the pre-concentrated analyte; and and providing hydrogen to the gas detector to provide hydrogen that functions as a combustion gas for operation of the gas detector, whereby the hydrogen functions as a mobile phase, a combustion gas, or both.

[0049] If hydrogen is supplied to the gas detector, the method may further comprise: providing hydrogen to an injector to provide hydrogen that serves as a mobile phase carrying the analyte; providing hydrogen to a pre-concentrator to provide hydrogen that functions as a mobile phase carrying the analyte; supplying hydrogen to a column that supplies hydrogen as a mobile phase carrying the pre-concentrated analyte; The method includes one, more than one, or all of the steps of supplying oxygen to the gas detector to provide oxygen that functions as a combustion gas for the operation of the gas detector, and supplying oxygen to provide oxygen generated as a by-product in the condensate. Thus, the oxygen functions as a mobile phase, a combustion gas, or both. Thus, even the by-product from the condensate can be used in the gas chromatograph. Oxygen is a suitable carrier gas if high temperatures in the column and preconcentrator are avoided.

[0050] It should be understood that the gas chromatograph system of claim 1, the aggregate of claim 18 and the method of claim 19 have similar and / or identical preferred embodiments, in particular the embodiments as defined in the dependent claims.

[0051] It should also be understood that a preferred embodiment of the present invention can be any combination of the dependent claims or the above embodiments with the corresponding independent claims.

[0052] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief explanation of the drawings]

[0053] [Figure 1] FIG. 1 shows a schematic diagram of a gas chromatograph system according to a first embodiment. [Figure 2] FIG. 2 shows a schematic diagram of a gas chromatograph system according to a second embodiment. [Figure 3] FIG. 3 shows a schematic diagram of a hydrogen supplying aggregate according to a first embodiment. [Figure 4] FIG. 4 shows a schematic diagram of a hydrogen supplying aggregate according to a second embodiment. [Figure 5] FIG. 5 is a schematic diagram of a hydrogen supplying aggregate according to a third embodiment. [Figure 6] FIG. 6 shows a schematic diagram of a hydrogen supplying aggregate according to a fourth embodiment. [Figure 7] FIG. 7 shows a schematic diagram of a hydrogen supplying aggregate according to a fifth embodiment. [Figure 8] FIG. 8 is a schematic diagram of a hydrogen supplying aggregate according to a sixth embodiment. [Figure 9] FIG. 9 shows a schematic diagram of a hydrogen supplying aggregate according to a seventh embodiment. [Figure 10] FIG. 10 shows a schematic diagram of a hydrogen supplying aggregate according to an eighth embodiment. [Figure 11] FIG. 11 is a schematic diagram of a hydrogen supplying aggregate according to a ninth embodiment. [Figure 12] FIG. 12 shows a schematic diagram of a hydrogen supplying aggregate according to a tenth embodiment. [Figure 13] FIG. 13 shows a flow chart illustrating a method of operating a gas chromatograph system. [Figure 14] FIG. 14 shows a flow chart illustrating a second embodiment of a method for operating a gas chromatograph system. DETAILED DESCRIPTION OF THE INVENTION

[0054] FIG. 1 schematically illustrates a gas chromatograph system 1000 for detecting volatile organic compounds according to one embodiment of the present invention. The gas chromatograph system 1000 includes a condenser 160 that supplies hydrogen 310, which serves as a mobile phase, and a gas chromatograph 100 (e.g., a micro gas chromatograph) coupled to the condenser 160 to receive the hydrogen 310. The condenser is formed according to any of the embodiments shown in FIGS. 3-12, with only the reference numeral "160" associated with FIG. 3 being shown for clarity. The gas chromatograph system 1000 further includes a system controller 400.

[0055] The gas chromatograph 100 includes an injector 110 for injecting an analyte 320 containing volatile organic compounds, and a pre-concentrator 120 for receiving, concentrating, and desorbing the analyte 320. The pre-concentrator 120 is coupled to the injector 110. Preferably, the pre-concentrator 120 is also coupled to a condensate 160.

[0056] Analyte 320 is transported from injector 110 to pre-concentrator 120 in transport direction T. Pre-concentrator 120 preferably includes a pre-concentrator heater 122 controlled by system controller 400. In the illustrated embodiment, injector 110 injects accelerated analyte into pre-concentrator 120. In an alternative embodiment (not shown), an inlet with an associated pump can be provided for injecting analyte 320. Pipe section 130 is coupled to condenser 160 and receives the accelerated flow of mobile phase provided by pressurized hydrogen 310, injecting hydrogen 310 into the flow path of analyte 320 either before entering pre-concentrator 120 or after exiting pre-concentrator 120.

[0057] The concentrator 160 is preferably connected to the preconcentrator inlet port 121 by a bypass 131 to provide a flow of oxygen 350 for preconcentrating volatile organic compounds in the analyte 320 .

[0058] The gas chromatograph 100 further includes a column 140 having a stationary phase 141. The column 140 receives pre-concentrated analytes 320 carried by a mobile phase provided by a constant gas flow driven by pressure within the condensate 160. The column 140 also includes a column heater 142 controlled by a system controller 400. Analytes 320 traversing the column 140 are separated by differential interactions with the stationary phase 141. The gas chromatograph 100 also includes a detector 150 positioned downstream of the column 140, which detects or identifies volatile organic compounds eluting from the column over time based on the rate at which the volatile organic compounds pass through the column 140. The detector 150 is in signal communication with the system controller 400 and provides raw data regarding the detected volatile organic compounds, particularly transit time. The hydrogen 310 and analytes 320 streams are ultimately exhausted via an exhaust port 112.

[0059] Figure 2 shows a schematic diagram of a gas chromatograph system 1000' for detecting volatile organic compounds according to a second embodiment of the present invention. In the embodiments shown in Figures 1 and 2, similar parts have the same reference numerals and reference is made to the above description of Figure 1. In the following, to avoid repetition, only the differences between the embodiments shown in Figures 1 and 2 will be discussed.

[0060] The gas chromatograph system 1000 includes a condensate 160 that supplies hydrogen 310, which serves as a combustion gas, and oxygen 350, which serves as a mobile phase, as a by-product, and a gas chromatograph 100 (e.g., a micro gas chromatograph) coupled to the condensate 160 to receive the hydrogen 310 and oxygen 350. The condensate is formed according to any of the embodiments shown in Figures 3-12, and only reference numerals associated with Figure 3 are shown for clarity.

[0061] Pipe section 130 couples condenser 160 and detector 150 to receive the accelerated flow of combustion gases supplied by pressurized hydrogen 310 and injects hydrogen 310 into the flow path of analyte 320 either before entering pre-concentrator 120 or after exiting pre-concentrator 120.

[0062] The aggregate 160 is preferably connected by a bypass 131 to the preconcentrator inlet port 121 or the column inlet port (not shown) to provide a flow of oxygen 350 which acts as a mobile phase to carry the analytes 320 in the transport direction T.

[0063] 3 shows a first embodiment of an aggregate 160. The aggregate 160 includes an aggregate inlet port 161 with an air filter 1611 for receiving ambient air 331, which serves as a hydrogen-containing medium 330, and an outlet port 162 coupled to a gas chromatograph 100, such as that shown in FIG.

[0064] Aggregate 160 further includes a PEM electrolyzer 163, a pressurized hydrogen buffer 164, and a water source 165. PEM electrolyzer 163 is configured for PEM electrolysis of water provided from water source 165 to generate hydrogen 310, which is stored in pressurized hydrogen buffer 164. Pressurized hydrogen buffer 164 is in fluid communication with outlet port 162 to provide hydrogen 310 to gas chromatograph 100.

[0065] 3 , the water source 165 is a condenser 1651 having a flow path 1652. The flow path 1652 has an actively cooled condenser surface 16521 and a condensate port 16522 that directs condensate 340 from the condenser surface 16521 toward a condensate buffer 1653. The flow path 1652 also has an oxygen port 16523 that allows oxygen 350 to rise from the condensate buffer 1653. The condensate port 16522 is located at a lowest point 16524 of the flow path 1652. Thus, the condensate 340 flows along the condenser surface 16521 toward the lowest point 16524, passes through the condensate port 16522, and is ultimately stored in the condensate buffer 1653. In the illustrated embodiment, the condensate buffer 1653 includes a sump 16531 having an overflow 16532 with a float switch 16535 to accommodate excess condensate, and a water seal 16533 to prevent air from entering the sump 16531. The float switch 16535 is preferably a mechanically controlled float switch that opens a flow path to the overflow when a predefined condensate level is reached. Alternatively, the float switch 16535 is preferably an electrically controllable float switch 16535.

[0066] The flow passage 1652 defines a lid 16534 of the sump 16531 that is provided with ports, such as a condensate port 16524 and an oxygen port 16523, to avoid evaporation of the stored condensate 340.

[0067] To cool the condenser 1651, the aggregate 160 further includes a cooling unit 166 including a Peltier element 1661 having a hot side 16611 and a cold side 16612. The cooling unit 166 further includes a heat sink 1662 disposed on the hot side 16611 of the Peltier element 1661, with the condenser 1651 disposed on the cold side 16612 of the Peltier element 1661. Thus, the hot side 16611 is attached to the heat sink 1662 and remains at or near ambient temperature, while the cold side 16612 is below room temperature. The cooling unit 166 further includes a fan 1664 that provides a cooling airflow to cool the heat sink 1662. The cooling unit 166 includes a cooling passageway 1663 associated with the heat sink 1662, through which the gas flow exiting the flow passageway 1652 may flow and ultimately exit the aggregate 160 via the fan 1664. The cooling unit 166 further includes an energy supply source 1665 coupled to the Peltier element 1661 to supply voltage or current such that a high temperature side 16611 of the Peltier element 1661 is formed adjacent to the heat sink 1662 and a low temperature side 16612 opposite the Peltier element 1661 facing the condenser surface 16521.

[0068] Aggregate 160 further includes a control unit 169 having an energy source 1691 and a pressure sensor 1692 that provides a signal to a PID controller 1693 to control energy source 1691 .

[0069] The control unit 169 controls the PEM electrolyser 163 depending on the pressure in the pressurized hydrogen buffer 164, which is monitored by a pressure sensor 1692. The amount of hydrogen produced by the PEM electrolyser 163 depends on the current or voltage supplied, in particular a DC voltage, and therefore the PEM electrolyser 163 can be controlled via the energy supply by the control unit 169.

[0070] Preferably, the control unit 169 also has a data interface 1694 for communication with a network (not shown) to receive network data. The PID controller 1693 controls the energy source 1691, preferably also based on the network data. Where the float switch 16535 is preferably an electrically controllable float switch 16535, the control unit 169 further has a condensate level monitoring unit 1695 for monitoring the condensate level in the condensate buffer 1653. The condensate level monitoring unit 1695 preferably includes a water level sensor for monitoring the actual condensate level in the condensate buffer 1653, and also preferably a humidity sensor for monitoring the humidity of the ambient air to determine future condensate levels. In a preferred embodiment (not shown), instead of or in addition to the first float switch 16535 between the condensate buffer 1653 and the PEM electrolyzer 163, a second float switch is positioned which selectively blocks the flow path (not shown) from the condensate buffer 1653 to the PEM electrolyzer to stop PEM electrolysis. Thus, if the condensate level is low or if overpressure in the pressurized hydrogen buffer 164 is detected by the pressure sensor 1692, the flow of condensate, and therefore hydrogen generation, is discontinued.

[0071] 4 shows a second embodiment of aggregate 170. Aggregate 170 includes aggregate inlet port 171 with air filter 1711 for filtering ambient air 331, which serves as the hydrogen-containing medium, and outlet port 172 coupled to gas chromatograph 100 as shown in FIG.

[0072] Aggregate 170 further includes a PEM electrolyzer 173, a pressurized hydrogen buffer 174, and a water source 175. PEM electrolyzer 173 is configured for PEM electrolysis of water provided from water source 175 to generate hydrogen, which is stored in pressurized hydrogen buffer 174. Pressurized hydrogen buffer 174 is in fluid communication with outlet port 172 to provide hydrogen 310 to gas chromatograph 100 via outlet port 172.

[0073] 4, the water source 175 includes a condenser 1751 having a flow path 1752. The flow path 1752 has a condenser surface 17521 defined by the contact surface 1731 of the PEM electrolyzer 173.

[0074] As described with respect to the first embodiment, the aggregate 170 includes a cooling unit 176 that cools the condenser 1751, having a heat sink 1762, associated cooling passages 1763, a fan 1764, and a Peltier element 1761 (hot side 17611 and cold side 17612).

[0075] Additionally, first and second thermal conductors 17512 and 17513 are provided, which thermally conductively couple the Peltier element 1761 and the condenser surface 17521 and are at least partially disposed in the flow path 1752. The water source 175 further includes a condensate buffer 1753 provided by open cell foam 17531 contained in a containment space 177. The containment space 177 is disposed in the flow path 1752 and is defined by the condenser surface 17521 and insulation 178 attached to the cold side 17612 of the Peltier element 1761. The first and second thermal conductors 17522 and 17523 may also at least partially define the containment space. The aggregate 170 further includes a control unit 179 having a controllable energy source 1791 and a pressure sensor 1792, which provide signals to a first PID controller 1793 of the control unit 179. The controllable energy source 1791 is a voltage supply in the illustrated embodiment.

[0076] In the illustrated embodiment, the control unit 179 controls the PEM electrolyzer 173 in response to the pressure in the pressurized hydrogen buffer 174, which is monitored by a pressure sensor 1792. The amount of hydrogen 310 generated by the PEM electrolyzer 173 depends on the energy provided (defined by the voltage or current supplied), and so the PEM electrolyzer 173 can be controlled via the supply of a DC voltage by the control unit 179.

[0077] The control unit 179 further includes a temperature control unit 1794 having a temperature sensor 17941 providing a sensor signal, an energy source 17942, and a second PID controller 17943. It should be understood that the temperature control unit 1794 is applicable to the embodiment shown in Figure 7 or any other embodiment having a Peltier element, but is not required for the use of a Peltier element. The second PID controller 17943 controls the Peltier element 1761 by regulating the energy supply by controlling the energy source 17942.

[0078] FIG. 5 illustrates a third embodiment of an aggregate 180. As described with respect to the first and second embodiments, the aggregate 180 includes an aggregate inlet port 181, an outlet port 182, and a PEM electrolyzer 183 that generates hydrogen 310, which is stored in a pressurized hydrogen buffer 184. The aggregate 180 includes a water source 185 that includes a water buffer 1851 and an oxygen buffer 186. The aggregate inlet port 181, which includes an exhaust gas filter 1812, is preferably connected to the exhaust port 112 of the gas chromatograph 100 (see FIG. 1) and receives exhaust gas 332 from the gas chromatograph 100, which contains hydrogen and thus serves as the hydrogen-containing medium 330. The aggregate 180 further includes a fuel cell 187 that filters volatile organic compounds, thereby generating electricity that is preferably stored in a battery 188 coupled to the fuel cell 187. The oxygen stored in the oxygen buffer can be used in the combustion process. The stored energy is preferably provided to gas chromatograph 100 (e.g., one of heaters 122, 142). In addition to generating electricity, hydrogen fuel cell 187 releases water during operation, which flows downward and is ultimately received and stored in water buffer 1851, while oxygen 350 from water buffer 1851 rises and is stored in oxygen buffer 186. Fuel cell 187 is preferably positioned above water buffer 1851 when aggregate 180 is in an upright position.

[0079] In an alternative embodiment (not shown), the generated electricity is fed directly to the PEM electrolyzer 183 .

[0080] Aggregate 180 further includes a control unit 189 having an energy source 1891 and a sensor 1892 (e.g., flow sensor 1892 in the illustrated embodiment) and providing signals to a PID controller 1893 to control energy source 1891. Controllable energy source 1891 is a voltage supply in the illustrated embodiment.

[0081] The control unit 189 controls the PEM electrolyser 183 depending on the pressure in the pressurized hydrogen buffer 184, which is monitored by a sensor 1892. Since the amount of hydrogen 310 generated by the PEM electrolyser 183 depends on the energy provided (defined by the supplied current or voltage, in particular a DC voltage), the PEM electrolyser 183 can be controlled via the supply of a DC voltage by the control unit 189.

[0082] The control unit 189 further includes a second pressure sensor 1894 to control the pressure of the incoming exhaust gas 332 and / or a third pressure sensor 1895 to control the pressure in the oxygen buffer 186 .

[0083] 6 shows a fourth embodiment of an aggregate 190. The aggregate 190 includes an outlet port 192 that is coupled to the gas chromatograph 100 as shown in FIG.

[0084] Aggregate 190 further includes a PEM electrolyzer 193, a pressurized hydrogen buffer 194, and a water source 195. PEM electrolyzer 193 is configured for PEM electrolysis of water provided from water source 195 to generate hydrogen 310, which is stored in pressurized hydrogen buffer 194. Pressurized hydrogen buffer 194 is in fluid communication with outlet port 192 to provide hydrogen 310 to gas chromatograph 100.

[0085] In the fourth embodiment, the water source 195 preferably includes a water-filled open-cell foam 1951 or a desiccant 1952 (such as zeolite or silica gel). Water 333 stored in the water source 195 functions as the hydrogen-containing medium 330 and is used in the PEM electrolysis performed by the PEM electrolyzer 193 as described above. Oxygen 350 generated during electrolysis rises through the water-filled open-cell foam 1951 when the aggregate 190 is in an upright position and passes through a gas diffusion layer 196 preferably disposed above the water-filled open-cell foam 1951. The gas diffusion layer 196 allows the oxygen 350 to flow outward while preventing liquid intrusion and water 195 leakage.

[0086] Aggregate 190 further includes a control unit 199 having an energy source 1991 and a pressure sensor 1992 that provides a signal to a PID controller 1993 to control energy source 1991. Controllable energy source 1991 is a voltage supply in the illustrated embodiment.

[0087] A control unit 199 controls the PEM electrolyser 193 in response to the pressure in the pressurized hydrogen buffer 194 which is monitored by a pressure sensor 1992 .

[0088] 7 shows a fifth embodiment of aggregate 200. Aggregate 200 includes an inlet port 201 that is coupled to exhaust port 112 of gas chromatograph 100 (see FIG. 1) for receiving exhaust gas 332 that includes exhaust filter 2012 and functions as hydrogen-containing medium 330. Aggregate 200 further includes a pressurized hydrogen buffer 204 that stores hydrogen 310, and an outlet port 202 that is fluidly connected to pressurized hydrogen buffer 204. Aggregate 200 also includes a hydrogen pump 205 that pumps filtered hydrogen 310 from exhaust filter 2012 to pressurized hydrogen buffer 204.

[0089] Aggregate 200 further includes a control unit 209 having an energy source 2091 and a first pressure sensor 2092 that provides a signal to a PID controller 2093 to control energy source 2091. Controllable energy source 2091 is a voltage supply in the illustrated embodiment.

[0090] The control unit 209 controls the hydrogen pump 205 in response to the pressure in the pressurized hydrogen buffer 204, which is monitored by a first pressure sensor 2092. The amount of hydrogen pumped by the hydrogen pump 205 depends on the energy provided (defined by the voltage or current supplied). The control unit 209 also has a second pressure sensor 2094 that monitors the pressure of the exhaust gas coming from the gas chromatograph 100, which is filtered by the exhaust gas filter 2012.

[0091] Figure 8 shows a sixth embodiment of an aggregate 210. Similar to the embodiment shown in Figure 5, the aggregate 210 has an aggregate inlet port 211, an outlet port 212, a fuel cell 217, and a PEM electrolyzer 213 that generates hydrogen 310 that is stored in a pressurized hydrogen buffer 214. Additionally, the aggregate has a control unit that has a PID controller 2193, a pressure sensor 2192, and an energy source 2191. The aggregate 210 further includes a water buffer 2151 and an oxygen buffer 216. See above description of Figure 5.

[0092] 5 by an idle mode storage unit 2141 that is in fluid communication with the pressurized hydrogen buffer 214. This idle mode storage unit 2141 includes a solid storage medium 21412 that forms a hydride upon contact with hydrogen, a pressure relief valve 21413 that releases pressure from the idle mode storage unit 2141, and a hydride storage heater 21412 that heats the solid storage medium 21412 to reform hydrogen from the formed hydride.

[0093] 9 shows a seventh embodiment of aggregate 220. Aggregate 220 includes aggregate inlet port 221 with air filter 2211 for receiving ambient air 331, which serves as hydrogen-containing medium 330, and outlet port 222 coupled to gas chromatograph 100, such as shown in FIG.

[0094] Aggregate 220 further includes a PEM electrolyzer 223, a pressurized hydrogen buffer 224, and a water source 225. PEM electrolyzer 223 is configured for PEM electrolysis of water provided from water source 225 to generate hydrogen 310, which is stored in pressurized hydrogen buffer 224. Pressurized hydrogen buffer 224 is in fluid communication with outlet port 222 to provide hydrogen 310 to gas chromatograph 100.

[0095] 9, the water source 225 is a condenser 2251 having a flow path 2252. The flow path 2252 has an actively cooled condenser surface 22521 and a condensate port 22522 that directs condensate 340 from the condenser surface 22521 toward a condensate buffer 2253. The flow path 2252 also has an oxygen port 22523 that allows oxygen 350 to rise from the condensate buffer 2253. The condensate port 22522 is located at a lowest point 22524 of the flow path 2252. Thus, the condensate 340 flows along the condenser surface 22521 toward the lowest point 22524, passes through the condensate port 22522, and is ultimately stored in the condensate buffer 2253. In the illustrated embodiment, the condensate buffer 2253 includes a sump 22531 with an overflow 22532 to accommodate excess condensate, and a water seal 22533 to prevent air from entering the sump 22531.

[0096] The flow passage 2252 defines a lid 22534 of the sump 22531 that is provided with ports, such as a condensate port 22524 and an oxygen port 22523, to prevent evaporation of the stored condensate 340.

[0097] To cool condenser 2251, aggregate 220 further includes a cooling unit 226. Cooling unit 226 has a heat sink 2262 and a fan 2264 that provides a cooling airflow to cool heat sink 2262. Cooling unit 226 has a cooling passage 2263 defined in heat sink 2262, through which the gas flow exiting flow path 2252 can flow and exit aggregate 220 via fan 2264 and heat sink 2262.

[0098] The agglomerate 220 includes an intermediate storage unit 223 located downstream of the agglomerate inlet port 221 and upstream of the PEM electrolyzer 223, the intermediate storage unit 223 including a desiccant bed 2231 for adsorbing water from the hydrogen-containing medium 330 and a heating section 2232 for evaporating the water stored in the desiccant bed 2231.

[0099] Water is collected from moist air and adsorbed at ambient temperature by blowing the air through a desiccant bed 2231, which may contain silica gel, zeolite, activated alumina, calcium chloride, etc., among others. When the desiccant bed 2231 is saturated or the condensate buffer 22531 is empty, the desiccant bed 2231 is heated by a heating element 2232 having an energy supply 2265 to desorb moisture from the desiccant bed 2231. The hot, humid air is condensed onto the condenser surface 22521. When the desiccant bed 2231 is dry, the energy supply 2265 turns off the heating element 2232, and the next moisture adsorption cycle begins.

[0100] A heat sink 2266 removes heat from the condenser surface 22521 during the desorption phase, maintaining the condenser surface 22521 at near ambient temperature. The condenser surface 22521 may be provided with a hydrophobic coating to facilitate removal of condensed water. The condenser surface may have features to increase its surface area. The dried air generated during the adsorption phase is used as input to the pre-concentrator 120 (see FIG. 1 ) to extract the analytes 320 contained in the air.

[0101] Aggregate 220 further includes a control unit 229 having an energy source 2291 and a pressure sensor 2292 that provides a signal to a PID controller 2293 to control energy source 2291 .

[0102] The control unit 229 controls the PEM electrolyser 223 depending on the pressure in the pressurized hydrogen buffer 224, which is monitored by a pressure sensor 2292. The amount of hydrogen produced by the PEM electrolyser 223 depends on the current or voltage supplied, in particular a DC voltage, and therefore the PEM electrolyser 223 can be controlled via the energy supply by the control unit 229.

[0103] FIG. 10 shows an eighth embodiment of the aggregate 230. The aggregate 230 includes an inlet port 231 equipped with an exhaust gas filter 2312, a pressurized hydrogen buffer 234 for storing hydrogen 310, and an outlet port 232 in fluid communication with the pressurized hydrogen buffer 234. The aggregate 230 further includes a hydrogen pump 235 for pumping filtered hydrogen 310 from the exhaust gas filter 2312 to the pressurized hydrogen buffer 234, as described in connection with the fifth embodiment shown in FIG. 7. The embodiment shown in FIG. 10 differs from the fifth embodiment in that the aggregate 230 includes a drying unit 233 for drying the hydrogen 310, located upstream of the outlet 232 in the transport direction T. The drying unit 233 includes either a drying desiccant 2331 for adsorbing moisture from the generated hydrogen 310 or a heater 2332 for heating the generated hydrogen 310.

[0104] FIG. 11 illustrates a ninth embodiment of the aggregate 240. The aggregate 240 includes a PEM electrolyzer 243, a pressurized hydrogen buffer 244, and a water source 245, as shown in FIG. 6. To avoid repetition, reference is made to the description of FIG. 4, and only the differences will be discussed below. The aggregate 240 further includes an oxygen buffer 246 in which rising oxygen 350 is stored. The aggregate 240 has a first outlet port 242.1 that couples to the detector 150 of the gas chromatograph 100, for example, to provide hydrogen 310 (see FIG. 2), which functions as a combustion gas. The aggregate 240 also has a second outlet port 242.2 associated with the oxygen buffer 246 that couples to the pre-concentrator 120 of the gas chromatograph 100, for example, to provide oxygen 350 (see FIG. 2), which functions as a mobile phase.

[0105] 12 shows a tenth embodiment of an aggregate 250. The aggregate 250 includes an aggregate inlet port 251 through which ambient air 331 enters, which serves as the hydrogen-containing medium, and an outlet port 252 that is coupled to a gas chromatograph 100 such as that shown in FIG.

[0106] Aggregate 250 preferably includes a PEM electrolyzer 253, a pressurized hydrogen buffer 254, and a water source 255. PEM electrolyzer 253 is configured for PEM electrolysis of water provided from water source 255 to generate hydrogen, which is stored in pressurized hydrogen buffer 254. Pressurized hydrogen buffer 254 is in fluid communication with outlet port 252 to provide hydrogen 310 to gas chromatograph 100 via outlet port 252. In the embodiment shown in FIG. 12, water source 255 includes a condenser (not shown).

[0107] The aggregate 250 includes a Nafion dryer unit 256 that removes moisture from the wet hydrogen serving as the hydrogen-containing medium 330 and processes the hydrogen-containing medium 330 to generate dry hydrogen 310. The Nafion dryer unit 256 can be used alone or in combination with the PEM electrolyzer 253, the pressurized hydrogen buffer 254, and the water source 255.

[0108] The Nafion dryer unit 256 includes a Nafion dryer 2561, an air conveying unit 2562, such as a pump or fan, a first Nafion dryer desiccant bed 2563 with a first bed heater 2564, and a second Nafion dryer desiccant bed 2565, preferably with a second bed heater 2566. The aggregate 250 further includes a first valve 2567.1 and a second valve 2567.2, both associated with the first Nafion dryer desiccant bed 2563. The first valve 2567.1 is disposed between the inlet 251 and the first Nafion dryer desiccant bed 2563. The second valve 2567.2 is located between the first Nafion dryer desiccant bed 2563 and the condenser 255 when the Nafion dryer unit is used with the condenser 255, or between the first Nafion dryer desiccant bed 2563 and an exhaust port (not shown).

[0109] The first valve 2567.1 is either a check valve that allows flow only from the inlet 251 to the first Nafion dryer desiccant bed 2563, or a controllable valve that selectively allows flow from the inlet 251 to the first Nafion dryer desiccant bed 2563. The second valve 2567.2 is either a check valve that allows flow only from the first Nafion dryer desiccant bed 2563 to the condenser 255 or to an exhaust (not shown), or a controllable valve that selectively allows flow.

[0110] The flow of incoming air 331 is selectively enabled by a first valve 2567.1, and the incoming air 331 is blown or pumped by an air conveying unit 2562 into a first Nafion dryer desiccant bed 2563, which stores moisture and thereby dries the incoming air 331. The dried air emerging from the first Nafion dryer desiccant bed 2563 is provided to the Nafion dryer 2561 as a purge gas.

[0111] In the Nafion dryer 2561, wet hydrogen, e.g., from the hydrogen buffer 254 or the outlet of the gas chromatograph 100, flows through the tube, while dry purge gas flows back around the outside of the tube. Although the partial pressure of water in the purge gas is less than that in the wet hydrogen gas, the membrane of the Nafion dryer 2561 selectively transfers water and water vapor from the sample gas through the membrane into the purge gas stream, outputting dry hydrogen. The Nafion dryer 2561 is coupled to the outlet 252 to provide dry hydrogen 310 to the gas chromatograph 100 to serve as a mobile phase or combustion gas.

[0112] By heating the first Nafion dryer desiccant bed 2563 with a first bed heater 2564 and reversing the flow with the air transfer unit 2562, the stored moisture is released and directed to the condenser 255 via a second valve 2567.2. The condenser 255 condenses the moist air from the first Nafion dryer desiccant bed 2563, the PEM electrolyzer 253 electrolyzes the condensate to generate hydrogen, and the hydrogen buffer 254 stores the hydrogen as described with respect to the embodiment shown in Figure 3. Alternatively, the moist air from the first Nafion dryer desiccant bed 2563 is exhausted through an exhaust port (not shown).

[0113] The agglomerator 250 preferably includes a third valve 2567.3 and a fourth valve 2567.4, both associated with the second Nafion dryer desiccant bed 2565. The third valve 2567.3 is located between the inlet 251 and the second Nafion dryer desiccant bed 2565. The fourth valve 2567.4 is located between the second Nafion dryer desiccant bed 2565 and the condenser 255, or between the second Nafion dryer desiccant bed 2565 and an exhaust port (not shown), if the Nafion dryer unit 256 is used with the agglomerator 255. When the first Nafion dryer desiccant bed 2563 becomes saturated, the air conveying unit 2562 reverses the flow so that the flow of the inlet air 331 is (selectively) enabled by the third valve 2567.3 and the inlet air 331 is blown or pumped by the air conveying unit 2562 into the second Nafion dryer desiccant bed 2565, which stores moisture and thereby dries the inlet air 331. The dried air resulting from the second Nafion dryer desiccant bed 2565 is provided to the Nafion dryer 2561 as a purge gas, as described above for the first Nafion dryer desiccant bed 2563. The second Nafion dryer desiccant bed 2565 provides a purge gas to the Nafion dryer 2561, and moisture from the second Nafion dryer desiccant bed 2565 is appropriately removed when the saturation limit is reached. To remove stored moisture from the second Nafion dryer desiccant bed 2565, a second bed heater 2566 can be used, the flow must be reversed by the air conveying unit 2562, and the moist air is directed to the condenser 255 or exhausted as described for drying the first Nafion dryer desiccant bed 2563.

[0114] Figure 13 shows a schematic diagram of a method 2000 of operating a gas chromatograph system 1000 according to the embodiment shown in Figure 1. The gas chromatograph system 1000 has an aggregate according to any of the embodiments shown in Figures 3-12.

[0115] In a first step 2100, pressurized hydrogen 310 is generated in the condensates 160, 170, 180, 190, 200, 210, 220, 230, 240, 250. In a second step 2200, the pressurized hydrogen is supplied to the gas chromatograph 100.

[0116] Preferably, providing 2200 hydrogen 310 to the gas chromatograph 100 includes providing 2210 hydrogen 310 to the injector 110 to provide hydrogen 310 that functions as a mobile phase carrying the analyte 320.

[0117] Additionally or alternatively, supplying 2200 hydrogen 310 to the gas chromatograph 100 preferably includes supplying 2220 hydrogen 310 to the pre-concentrator 120 to provide hydrogen 310 that functions as a mobile phase carrying the analytes 320.

[0118] Additionally or alternatively, supplying 2200 hydrogen 310 to the gas chromatograph 100 preferably includes supplying 2230 hydrogen 310 to the column 140 to provide hydrogen 310 that functions as a mobile phase carrying the pre-concentrated analytes 320.

[0119] In a third step 2300, the analytes 320 are injected into one or more pre-concentrators 120. A fourth step 2400 involves concentrating the analytes 320, including volatile organic compounds, in one or more pre-concentrators 120. Then, in a fifth step 2500, the analytes 320 are conveyed in a transport direction T towards the column 140.

[0120] In a sixth step 2600, the method 2000 includes directing the pre-concentrated analytes 320 carried by the mobile phase 310 through a column 140. The column 140 includes a stationary phase 141. In a final step 2700, the method 2000 includes detecting the volatile organic compounds eluted from the column 140 with a gas detector 150.

[0121] FIG. 14 illustrates an alternative embodiment of a method 3000 of operating the gas chromatograph system 1000' shown in FIG.

[0122] In a first step 3100, pressurized hydrogen 310 and by-product oxygen 350 are generated in the condensates 160, 170, 180, 190, 200, 210, 220, 230, 240, and 250. In a second step 3200, the pressurized hydrogen is supplied to the gas chromatograph 100. Supplying (3200) the hydrogen 310 to the gas chromatograph 100 includes supplying (3210) the hydrogen 310 to the gas detector 150, where the hydrogen 310 functions as a combustion gas for operation of the gas detector 150. Furthermore, the method 3000 includes supplying (3220) the oxygen 350 generated as a by-product in the condensates 160, 170, 180, 190, 200, 210, 220, 230, 240, and 250 to the gas chromatograph 100.

[0123] Preferably, providing 3220 oxygen 350 includes providing 3221 oxygen 350 to injector 110 to provide oxygen 350 that functions as a mobile phase carrying analyte 320 .

[0124] Additionally or alternatively, supplying 3220 oxygen 350 includes supplying 3222 oxygen 350 to pre-concentrator 120 to provide oxygen 350 that functions as a mobile phase carrying analyte 320.

[0125] Additionally or alternatively, supplying (3220) oxygen 350 includes supplying (3222) oxygen 350 to column 140 to provide oxygen 350 that functions as a mobile phase carrying pre-concentrated analytes 320.

[0126] In a third step 3300, the analyte 320 is injected into one or more pre-concentrators 120. A fourth step 3400 involves concentrating the analyte 320, including volatile organic compounds, in one or more pre-concentrators 120. Then, in a fifth step 3500, the analyte 320 is conveyed in a transport direction T towards the column 140.

[0127] In a sixth step 3600, the method 3000 includes directing the pre-concentrated analytes 320 carried by the mobile phase provided by oxygen 350 through a column 140. The column 140 includes a stationary phase 141. In a final step 3700, the method 3000 includes detecting the volatile organic compounds eluted from the column 140 with a gas detector 150. The gas detector 150 detects the volatile organic compounds by a combustion process under the consumption of hydrogen 310 provided by the condensates 160, 170, 180, 190, 200, 210, 220, 230, 240, 250.

[0128] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0129] In the claims, the word "comprising" does not exclude other elements or steps and the word "a" or "an" does not exclude a plurality.

[0130] A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0131] Any reference signs in the claims should not be construed as limiting the scope.

[0132] The present invention relates to a gas chromatographic system for detecting volatile organic compounds in an analyte, the gas chromatograph having an injector for injecting the analyte, a preconcentrator, a column with a stationary phase, and a gas detector for detecting analyte components eluted from the column. The present invention proposes an aggregate having an outlet coupled to the gas chromatograph, for receiving and treating a hydrogen-containing medium to generate hydrogen and supplying the hydrogen to the gas chromatograph. The present invention further relates to such an aggregate and to a method for operating the chromatographic system.

Claims

1. 1. A gas chromatograph system for detecting volatile organic compounds in a sample, comprising: a gas chromatograph having an injector for injecting the analyte into the gas chromatograph, a preconcentrator for concentrating the injected analyte, a column having a stationary phase, and a gas detector for detecting the analyte components eluted from the column; an aggregate having an outlet coupled to the gas chromatograph, the aggregate receiving and processing a hydrogen-containing medium to generate hydrogen and providing the hydrogen to the gas chromatograph; 1. A gas chromatograph system comprising:

2. 10. The gas chromatograph system of claim 1, wherein the aggregate includes a water source and a polymer electrolyte membrane (PEM) electrolyzer for electrolyzing the water.

3. the aggregate has an aggregate inlet port equipped with a filter for filtering the hydrogen-containing medium; the hydrogen-containing medium is ambient air and the filter is an air filter that filters incoming ambient air; The hydrogen-containing medium is a hydrogen-containing exhaust gas from the gas chromatograph, and the filter is an exhaust gas filter that filters the exhaust gas that flows in, or 3. The gas chromatograph system of claim 1, wherein the hydrogen-containing medium is a hydrogen-containing exhaust gas from the gas chromatograph, and the filter is a PEM fuel cell that filters the incoming exhaust gas.

4. 4. The gas chromatograph system of claim 1, wherein the condensate comprises a pressurized hydrogen buffer in fluid communication with the outlet to provide a flow of pressurized hydrogen.

5. the water source includes a condenser for acquiring water and a condensate buffer for storing water, the condenser including a flow path having a condenser surface and a cooling unit for cooling the condenser surface; or the water source is located adjacent to the PEM electrolyzer; and Water-filled open cell foam, at least one of a desiccant bed and a desiccant having a heating portion for evaporating water stored in the desiccant bed; or 5. The gas chromatograph system of claim 2, wherein the water source includes a water buffer, the aggregate includes a PEM fuel cell for generating electricity to produce water stored in the water buffer, and oxygen rising from the water buffer is stored in an oxygen buffer.

6. 6. The gas chromatograph system of claim 5, wherein the cooling unit includes a Peltier element, a heat sink, and an energy supply coupled to the Peltier element to provide a voltage thereto, the Peltier element having a hot side adjacent the heat sink and an opposite cold side facing the condenser surface.

7. The concentrate buffer may further comprise: a condensate port connecting the flow path and the condensate buffer to direct condensate from the condenser surface to the condensate buffer; and an oxygen port that allows oxygen to rise from the condensate buffer into the flow path when the aggregate is in an upright position; 7. The gas chromatograph system of claim 5, further comprising a lid including one or more of:

8. 8. The gas chromatograph system of claim 5, wherein the condensate buffer comprises a sump located below the condenser and above the PEM electrolyzer when the aggregate is in an upright position.

9. the condenser comprises a number of heat conductors connecting the PEM electrolyzer and the Peltier element for cooling a contact surface of the PEM electrolyzer that at least partially defines the condenser surface, a containment space is formed between the number of heat conductors, the contact surface, and a thermal insulator attached to the cold side of the Peltier element; The gas chromatograph system according to claim 5 or 6, wherein the containing space defines the flow path and contains the condensate buffer.

10. 5. The gas chromatograph system of claim 4, wherein the condenser includes a hydrogen pump that pumps filtered hydrogen from the exhaust gas filter to the pressurized hydrogen buffer.

11. The aggregate comprises a controllable energy source for supplying a voltage or a current, at least one sensor for providing a sensor signal, and a control unit comprising a controller, in particular a PID controller, for controlling the supply of the voltage or current based on the sensor signal, the control unit comprising: the controller controls the supply of voltage or current supplied by the energy source to the PEM electrolyzer based on a sensor signal of the at least one sensor, thereby controlling hydrogen capture in the pressurized hydrogen buffer, wherein the at least one sensor is a pressure sensor that detects the pressure in the pressurized hydrogen buffer or a flow sensor that detects hydrogen flow to the pressurized hydrogen buffer; the controller controls the supply of voltage or current supplied by the energy source to the cooling unit based on the sensor signal, thereby controlling the temperature of the condenser surface, wherein the at least one sensor is a temperature sensor that detects the temperature of the condenser surface; the controller controls the amount of condensate stored in the condensate buffer by controlling the supply of voltage or current supplied by the energy source to the cooling unit based on a signal from a condensate level monitoring unit; the controller controlling a float switch associated with the condensate buffer to control the amount of condensate stored in the condensate buffer; the controller controls the supply of voltage or current supplied by the energy source to the pump based on a sensor signal of the at least one sensor, thereby controlling hydrogen acquisition in the pressurized hydrogen buffer, wherein the at least one sensor is a pressure sensor that detects the pressure in the pressurized hydrogen buffer or a flow sensor that detects the flow of hydrogen into the pressurized hydrogen buffer; or the controller controls the amount of water stored in the water buffer by controlling the supply of voltage or current supplied by the energy source to the fuel cell based on the sensor signal of the at least one sensor, wherein the at least one sensor is a pressure sensor that detects the pressure in the pressurized hydrogen buffer or a flow sensor that detects the flow of hydrogen to the pressurized hydrogen buffer.

11. The gas chromatograph system of claim 2, wherein the gas chromatograph system performs one, more than one, or all of the following:

12. 12. The gas chromatograph system of claim 1, wherein the condensate includes an idle mode storage unit in fluid communication with the pressurized hydrogen buffer, the idle mode storage unit including a solid storage medium that forms a hydride upon contact with hydrogen, a pressure relief valve that releases pressure from the idle mode storage unit, and a hydride storage heater that heats the solid storage medium to reform hydrogen from the formed hydride.

13. 13. The gas chromatograph system of claim 3, wherein the aggregate includes an intermediate storage unit disposed downstream of the aggregate inlet port and upstream of the PEM electrolyzer, the intermediate storage unit having a desiccant bed for adsorbing water from the hydrogen-containing medium and a heating section for evaporating water stored in the desiccant bed.

14. 14. The gas chromatograph system of claim 1, wherein the condenser includes a drying unit disposed upstream of the outlet for drying hydrogen, the drying unit including a dry adsorbent for storing moisture from the generated hydrogen.

15. 6. The gas chromatograph system of claim 1, further comprising a Nafion dryer unit for removing moisture from the hydrogen-containing medium, the Nafion dryer unit comprising a Nafion dryer, an air conveying unit, and at least one Nafion dryer desiccant bed.

16. The outlet is for supplying hydrogen to the gas chromatograph. the injector for supplying hydrogen, which serves as a mobile phase for carrying the analyte in a transport direction; the pre-concentrator for supplying hydrogen which serves as a mobile phase for carrying the analyte in the transport direction; said column for supplying hydrogen to serve as a mobile phase for carrying said pre-concentrated analyte in said transport direction; said gas detector for supplying hydrogen to serve as a combustion gas for the operation of said gas detector 16. The gas chromatograph system of claim 1, coupled to one, more than one, or all of:

17. the aggregates produce oxygen as a by-product; the injector for supplying oxygen which serves as a mobile phase for carrying the analyte in the transport direction; the preconcentrator for supplying oxygen to serve as a mobile phase for carrying the analyte in the transport direction; the column for supplying oxygen, which serves as a mobile phase for carrying the pre-concentrated analyte in the transport direction; or said preconcentrator for supplying oxygen to preconcentrate said analyte; 17. The gas chromatograph system of claim 1, wherein the gas chromatograph system is coupled to the gas chromatograph to supply oxygen to at least one of:

18. 18. An aggregate for a gas chromatographic system for providing a hydrogen gas stream, in particular a gas chromatographic system according to any one of claims 1 to 17, comprising: an aggregate having an outlet for coupling to said gas chromatograph system, for receiving and processing a hydrogen-containing medium to generate hydrogen, and for supplying hydrogen to the gas chromatograph in the transport direction;

19. A method for operating a gas chromatographic system, in particular a gas chromatographic system according to any one of claims 1 to 16, comprising the steps of: generating pressurized hydrogen for a gas chromatograph; supplying the pressurized hydrogen to a gas chromatograph; injecting an analyte into the preconcentrator of the gas chromatograph; concentrating the analyte containing volatile organic compounds in the pre-concentrator; carrying the analyte with the mobile phase in the transport direction from the preconcentrator to a column containing a stationary phase; directing the pre-concentrated analytes carried by the mobile phase through the column; detecting the volatile organic compounds eluted from the column with a gas detector; A method comprising:

20. The step of supplying hydrogen to the gas chromatograph comprises: supplying hydrogen to the injector to provide hydrogen that serves as a mobile phase for carrying the analyte; providing hydrogen to the pre-concentrator to provide hydrogen that functions as a mobile phase for carrying the analyte; supplying hydrogen to the column to provide hydrogen that serves as a mobile phase for carrying the pre-concentrated analyte; and supplying hydrogen to the gas detector to provide hydrogen to serve as a combustion gas for operation of the gas detector; 20. The method of claim 19, comprising one, more, or all of:

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