JP5731010B2 - Gas-liquid contact extraction method and apparatus - Google Patents

Description

  The present invention relates to a dissolved substance in a liquid (hereinafter referred to as “GC”) or a gas chromatograph mass spectrometer (hereinafter sometimes referred to as “GC / MS”). The present invention relates to a method and apparatus for efficiently gas-liquid extraction of analytical species in the analysis of “analytical species”.

  As an analysis method using gas-liquid extraction operation in the analysis by GC or GCMS, there are a purge and trap (hereinafter sometimes referred to as “P & T”) method and a headspace (hereinafter sometimes referred to as “HS”) method. is there. These are analytical methods described in the Water Supply Law under the jurisdiction of the Ministry of Health, Labor and Welfare.

(1) P & T method and its problems In the P & T method, an analyte dissolved in a solution is forcibly extracted into a gas phase by flowing a gas having a low solubility in the solution, and the extracted analyte is temporarily used as an adsorbent. This is a method of concentrating the analyte by holding it. Thereafter, the adsorbent is rapidly heated, the analyte is heated and desorbed from the adsorbent, and the analyte is introduced into the GC analytical column.

上記式１に於いて、Ｆはパージガス流量、ｔはパージ時間、Ｋは分配係数、Ｖ_Ｌは試料の体積、Ｖ_Ｇは容器の気相体積、ｍ_０は元の溶液中の分析種の量、ｍ_ａは気相に出た分析種の量である。The purge efficiency R in the ideal state can be obtained from Equation 1 for extracting the analysis species from the water in the P & T method.
(Formula 1)

In the above equation 1, F is the flow rate of the purge gas, t is the purge time, K is the partition coefficient, V _L is the volume of the sample, V _G is the gas phase volume of the vessel, m ₀ is the amount of analyte in the original solution , M _a is the amount of the analyte that has entered the gas phase.

  In order to increase the recovery rate as the distribution coefficient increases, the total purge flow rate must be increased. Next, it is the process of holding the analyte in the extracted purge gas with the adsorbent. Since the adsorbent used has a breakthrough volume for each analyte, consider the total flow rate of the purge gas. There is a need.

  From Equation 1, it can be seen that the purge efficiency increases by increasing the purge gas flow rate, decreasing the partition coefficient K, decreasing the sample volume, and decreasing the gas phase portion of the purge vessel.

Problems of the P & T method 1) Recovery rate of water-soluble components with a large distribution coefficient In the P & T method, nonpolar components with a small distribution coefficient that coexist in water are mainly recovered even if the total purge flow rate is increased, and the distribution coefficient K is large. It is difficult to improve the recovery rate of water-soluble components.

  The musty odor component in tap water is said to have a threshold of 1 ppt. That is, even if 1 pg of analytical species exists in 1 ml of tap water, a person recognizes it as a musty odor. It is said that the olfactory threshold of trichloroanisole caused by the hypochlorous acid sterilization residue and phenols is 0.03ppt. On the other hand, the measurement sensitivity of GC / MS does not reach human sensations. Although it depends on the amount of impurities, etc. that are not to be measured, the analytical species cannot be detected unless several pg of analytical species are introduced into the GC separation column and reach the mass spectrometer.

  In the measurement methods of the P & T method and the HS method described above, it is recommended to use 20 ml of sample water in the analysis (corresponding to 20 pg when the mold odor component concentration is 1 ppt).

  When the sample extraction temperature is 40 ° C., benzene can be recovered 100% at a total purge gas flow rate of 800 ml, but 2-MIB can only recover 21.8% and Geosmin can only recover 21.4%. Even if the total flow rate of the purge gas is increased for the purpose of improving the recovery rate of the analyte having a large distribution coefficient, the analyte will break through unless the breakthrough capacity of the adsorbent is taken into consideration. That is, there is an upper limit to the total flow rate of the purge gas depending on the adsorbent used (Table 1).

2) Occurrence of problems due to increase in purge flow rate In the conventional P & T purge tube, droplets scatter as the purge flow rate increases. In the actual sample, metal, rust, microorganisms, bacteria, etc. accumulate on the pipe and cause trouble of the equipment. In addition, it is said that bubbling of the sample due to purging reduces gas-liquid extraction efficiency. When the purge flow rate is slow, the analysis time becomes long when trying to increase the total amount of purge gas (see Anal. Chem., 58 (1986) 1822, James F. Pankow).

3) In the P & T method, where the mass transfer of analyte species in water to the gas phase is slow, the cause of the time required for gas-liquid equilibration is: a) uniform gas phase concentration in the bubble, b) material at the gas-liquid (bubble) interface Movement, c) Mass movement in water can be considered, and c) has the largest contribution.

  For this reason, it is necessary to increase the gas-liquid contact area by making many small bubbles in the purge pipe and flowing the bubbles uniformly in the purge pipe, thereby improving the contact efficiency between the gas and the liquid.

  Therefore, it is important to install a fine mesh sintered filter called frit in the purge pipe. However, in the actual sample, particulate matter, algae and the like accumulate in the frit and cause contamination of the sample, and maintenance such as a change in the recovery rate and frequent frit is required.

4) Since the cryofocus P & T method has poor extraction efficiency, a cryofocus using liquid nitrogen is used in order to introduce the entire amount of the extracted analyte into GC or GC / MS. When continuous automatic analysis for 24 hours is carried out at a water purification plant or the like, it is necessary to supply liquid nitrogen, and it is difficult to completely unmanned, and the analysis cost is disadvantageous.

(2) HS method and its problems In the HS method, a sample is placed in a tightly sealed vial, heated at a constant temperature for a certain time, and kept warm to obtain a gas-liquid equilibrium state. It is a method of analysis.

上記の数式において、Ｃ_Ｇは気相中の分析種の濃度（ｇ／ｃｍ^３）、Ｃ_Ｌは液相中の分析種の濃度（ｇ／ｃｍ^３）、Ｖ_Ｇは気相の体積、Ｖ_Ｌは液相の体積、Ｃ_Ｌ ^０は平衡前の試料濃度である。Problems of the HS Method The concentration in the gas phase by the HS method can be obtained from Equation 2.
(Formula 2)

In the above equation, _{C G} is analyte concentration in the gas phase _{^{(g / cm 3), C}} L is analyte concentration in the liquid phase _{^{(g / cm 3), V}} G is the volume of gas-phase, V _L is the volume of the liquid phase, and C _L ⁰ is the sample concentration before equilibration.

From Equation 2, when the water-soluble component has a large partition coefficient K, the recovery rate of the analyte extracted in the gas phase is poor. To increase the C _G, it is necessary to decrease the distribution coefficient K, increases the vial temperature (for water samples) to salting perform, it is understood that the addition of an acid or a base is effective.
In addition, reducing β (increasing the amount of sample, decreasing the gas phase portion) is not very effective in improving sensitivity.

  Recently, in order to increase the sensitivity by the HS method, a method of sampling the gas phase in a gas-liquid equilibrium state several times from a sample vial, concentrating it in an adsorption tube, desorbing it by rapid heating, and introducing it into an analytical column (multiple HS method) Has been devised. In this multiple HS method, an improvement in sensitivity can be expected by concentrating multiple times for an analyte with a large partition coefficient K. However, it takes time to reach gas-liquid equilibrium, and sampling must be performed in a gas-liquid equilibrium state multiple times, which increases the time required for the sample pretreatment operation.

  Regardless of the multiple HS method in which the headspace gas after gas-liquid equilibration is concentrated and collected in the adsorbent many times, or the P & T method in which gas-liquid equilibria are created with microbubbles and extracted continuously. The HS method is different in batch processing and the P & T method is different in continuous extraction. However, the HS method and the P & T method are the same in principle, and the extraction amount depends on the distribution coefficient.

  The big problem of both is that the gas concentration of the analyte immediately after starting the extraction operation after putting the sample in the container or the purge pipe is high, the analyte is extracted from the liquid and the concentration of the solution is low, Since the distribution coefficient (ratio of concentration in solution to gas) is constant, the concentration in gas also decreases. In other words, the second half of the extraction operation is that the amount of extracted analyte is reduced while the P & T method consumes a large amount of extracted gas.

  Gas-liquid countercurrent contact extraction is known as a gas-liquid extraction operation that has the potential to solve the problems of the conventional method. This technique is employed when a predetermined component is recovered or removed from a large amount of liquid in the chemical industry field such as a plant (see Japanese Patent Application Laid-Open No. 10-57947 and Japanese Patent No. 306894). .

  In Japanese Patent Application Laid-Open No. 10-57947, the ammonia-containing liquid is scraped into the gas phase and refined to extremely increase the gas-liquid contact area and increase the efficiency of ammonia emission into the gas phase. This is a mass separation system for ammonia. For this reason, it is impossible to adapt to a method and apparatus for analyzing a small amount or a small amount of sample.

  Further, in Japanese Patent No. 306894, a structure in which a pipe for flowing a liquid from above and a gas from below is bent in a vertical direction, and a capillary is formed on the inner wall of the pipe as a structure of the pipe. A configuration is shown in which a wick for liquid phase transfer is installed depending on the phenomenon.

  However, if the reaction tower (pipe) pointed out here is inclined, the liquid does not come into contact with the packing 6 and a gas-liquid contact surface cannot be obtained sufficiently. For this purpose, a wick is installed on the inner wall surface of the tube, and the liquid is moved in the liquid phase by capillary action. However, this liquid phase transfer by capillary action can be used when the amount of liquid is large, but the time control is not effective in the analysis process of a small amount of liquid sample, and fine particles are present in the sample liquid. If present, the fine particles may accumulate on the rotating member or wick and contaminate the inner wall surface of the tube, which is not suitable for continuous operation of the apparatus. Furthermore, when a surfactant is mixed into a liquid sample, or when the liquid sample is an effervescent beverage, there is foaming, and the sample itself may be difficult to extract, making practical use impossible.

  In the gas-liquid contact extractor, the “Analytical Sample Pretreatment Handbook” (Maruzen, 2003, as a document suggesting the use in GC analysis in which the sample liquid is flowed from above the spiral tube and purge gas is sent from below. By Masahiro Furuno). However, the apparatus shown in this document is configured so that the sample liquid and the purge gas are allowed to flow away from each other, and the control of the sample liquid and the purge gas is not taken into consideration, and the control of the relationship between the two is not taken into consideration. The interaction between gas and liquid is apparent, and the extraction efficiency between gas and liquid is extremely low, and it is difficult to use an extracted sample as an analytical sample, and it has not been put into practical use.

Japanese Patent Laid-Open No. 10-57947 Japanese Patent No. 306894

Anal. Chem. 58 (1986) 1822; James F .; Pankow "Analytical Sample Pretreatment Handbook" (Maruzen, 2003, Masahiro Furuno)

  In GC or GC / MS analysis, for analytes with a large partition coefficient and analytes with a small olfactory threshold, gas-liquid contact extraction is performed in view of the importance of quickly moving the analyte present in the liquid phase to the gas phase. With respect to the use of, it is necessary to obtain a method and apparatus for bringing the analyte concentration of the gas phase portion at the purge gas outlet close to the theoretical value. Also, by elucidating these methods and devices, the extraction efficiency equivalent to the theoretical value can be obtained for the analytical species, thereby allowing GC or GC / MS analysis from sampling at a water purification plant without the need for cryofocusing. In such a case, there is a need for a method and an apparatus that enable complete unmanned automatic analysis.

  The P & T method and the HS method are methods that perform analysis using a liquid sample stored in a fixed space, and it is impossible to supply and analyze a continuous sample over a long period of time. When monitoring analytes in tap water, analytes in river water, or analytes in sample liquids for quality control of beverage manufacturers, etc., perform analysis by collecting a certain amount of human samples over time. There must be. Therefore, there is a need for a sample introduction apparatus that introduces a sample from collection of a sample to GC or GC / MS continuously and unattended on a 24-hour basis.

  In addition, samples of “specimens with a high partition coefficient in vapor-liquid equilibrium”, “species with high water solubility”, or “species with low olfactory threshold” are collected 24 hours a day, unattended and continuously. There is a growing need for sample introduction from GC to GC or GC / MS. However, with the conventional P & T method and HS method, it is difficult to analyze by GC or GC / MS of an analysis species having “a large partition coefficient in vapor-liquid equilibrium”, “high water solubility”, and “low olfactory threshold” .

  In order to solve the above problems, the sample liquid is continuously supplied to the gas-liquid extraction part, the supply balance between the purge gas and the sample liquid is ensured, the analyte is rapidly transferred to the gas phase, and is led to the collection tube. There is a need for a method and apparatus for introducing a sample into a GC or GC / MS, i.e., a method and apparatus for performing extraction at all times of continuous sample flow.

  Furthermore, for continuous GC or GC / MS analysis for a long period of time, an artificial operation such as supply of liquid nitrogen for the implementation of cryofocusing is unnecessary, and a component having a large distribution coefficient in the P & T method and the HS method. There is a need for a method and apparatus that can address problems such as recovery, length of processing time, etc., that is, a method and apparatus that performs extraction over the entire time that a liquid sample is continuously flowed.

  Therefore, the present invention uses a gas-liquid contact extractor that continuously introduces sample liquid from above and purge gas from below, and makes the sample liquid and purge gas come into gas-liquid contact to extract the analyte in the sample liquid. In the liquid contact extraction method, the sample liquid is discharged through the liquid reservoir provided in the discharge pipe connected to the lower part of the gas-liquid contact extractor, and the purge gas is prevented from flowing out from the liquid reservoir. A gas-liquid contact extraction method is provided.

  In the gas-liquid contact extraction method, the sample liquid is preheated to an extraction temperature in the gas-liquid contact extractor before supplying the sample liquid to the gas-liquid contact extractor. An extraction method is provided.

  The gas-liquid contact extraction method is characterized in that a water-soluble component having a partition coefficient K greater than 1 or an analyte present in a liquid having an olfactory threshold lower than 10 ppt (pg / ml) is gas-liquid contact extracted. A gas-liquid contact extraction method is provided.

  In the gas-liquid contact extraction method, the gas-liquid contact extractor is installed in a temperature-controllable oven, and the flow path to the collection tube where the gas-liquid contact-extracted analyte is concentrated is set to the oven temperature ( There is provided a gas-liquid contact extraction method characterized in that an analytical species extracted by gas-liquid extraction is concentrated in the collection tube at a temperature equal to or higher than the gas-liquid extraction temperature).

  Furthermore, a gas-liquid contact extractor for supplying a liquid sample from above and a purge gas from below is provided, and a discharge pipe is connected to the lower portion of the gas-liquid contact extractor while discharging the sample liquid to the discharge pipe. There is provided a gas-liquid contact extraction device provided with a liquid reservoir for preventing discharge of purge gas.

  Further, in the gas-liquid contact extraction device, a gas-liquid contact extraction device is provided, wherein the contact surface with the sample liquid of the gas-liquid contact extractor is subjected to surface treatment, and the contact surface is in an extended wet state. To do.

  In the gas-liquid contact extraction apparatus, the gas-liquid contact extraction apparatus is characterized in that the surface treatment is either hydrophilic treatment or water repellent treatment.

  Furthermore, the liquid sample supply unit is connected to the gas-liquid contact extraction device via a syringe pump and a selector valve for switching the flow path, and the analytes extracted by the gas-liquid contact extraction device are collected. Provided is an automatic liquid sample supply device characterized by being sent to a tube.

  According to the present invention as described above, in supplying the liquid sample to the gas-liquid contact extractor, the liquid sample is supplied at the extraction temperature, and the gas-liquid contact at the gas-liquid boundary surface is sufficiently and rapidly performed. As a result, the liquid sample can achieve gas-liquid equilibrium in a short time, and the analyte can be secured quickly and reliably.

  Also, by providing a liquid reservoir in the sample liquid discharge part, the purge gas is prevented from being discharged from the discharge part, and the supply amount of the sample liquid to the gas-liquid contact extractor, the purge gas pressure, and the purge gas flow rate are matched. It is possible to increase the gas-liquid contact rate, increase the extraction efficiency of the analyte, and reliably carry out the flow of the analyte to a concentrating tube having a constant flow rate.

  In addition, by providing a liquid reservoir, the analyte concentration in the gas phase can be made closer to the theoretical value, and the analysis species with a high partition coefficient, high water solubility, and low olfactory threshold, which have been difficult in the past, can be obtained. It became easy to analyze.

  In addition, in quality control of tap water, river water, and beverages, it has become possible to introduce samples unattended from sampling to extraction and analysis continuously for a long time without manual operation.

System configuration schematic explanatory diagram including the automatic liquid sample supply apparatus of the present invention Illustration of movement of analyte due to vapor-liquid equilibrium Comparison of extraction efficiency of 2-MIB and Geosimin according to the difference in purge gas flow rate and sample water flow rate Chromatogram of 2-MIB and Geosimin through reproducibility test Same as above Same as above Chromatogram of the test when the concentration is changed Same as above 2-MIB calibration curve linear test results Geosimin calibration curve linear inspection result diagram Chromatogram of 2,4,6-trichloroanisole analysis result Chromatogram of 1,4-dioxane analysis results in tap water Chromatogram of sesame oil analysis results Chromatogram of 2-MIB and Geosimin without preheating test Same as above Chromatogram of preheated test SIM chromatogram comparing concentration of 10ppt musty odor standard water (a) and river water (b) with turbidity of 150 degrees (kaolin) Total ion current chromatograms of commercial tea beverages compared for aroma components immediately after opening and after 10 days Total ion current chromatograms analyzed for volatile organic compounds in commercial milk.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows an online connection of GC or GC / MS that can be used for quality control in tap water and beverage factories, which can supply river water and tap water by flow from a source such as a large storage tank. It is a block diagram which shows an example of a structure of the system 500 analyzed by FIG. This system 500 includes the gas-liquid contact extractor 2, the gas-liquid contact extraction device 200, and the automatic liquid sample supply device 100 of the present invention, and is a system that performs the gas-liquid contact extraction method of the present invention. The tube 1 constitutes the main body of the gas-liquid contact extractor 2 and is installed in a slanting manner. The tube 1 is preferably a spiral tube, but a straight tube, a bent tube or the like can also be used.

  The automatic liquid sample supply apparatus 100 includes a gas / liquid contact extractor 2 and a gas / liquid contact extraction apparatus 200. The gas-liquid contact extractor 2 is formed of glass, metal, synthetic resin, or the like, and has an inner diameter of 3 to 10 mm and an inclination angle of 15 ° to 45 ° with respect to the horizontal. When the gas-liquid contact extractor 2 is formed of a spiral tube, its length and winding diameter are not particularly limited. However, the length may be 500 to 1500 mm and the winding diameter may be 50 to 200 mm.

  The gas-liquid contact extractor 2 performs surface treatment on the contact surface with the sample liquid, that is, the inner surface of the gas-liquid contact extractor 2 to improve the “wetting property” when contacting with the sample liquid. It is preferable to make a gas-liquid contact area large by adopting the form of "". As for the wetness of the liquid on the inner surface of the gas-liquid contact extractor 2, there are extended wetness, immersion wetness, and adhesion wetness as shown in the science chronology. It is preferable.

  In addition, when surface treatment for improving wettability is necessary, the treatment contents differ depending on the sample. Water samples such as rivers, tap water, soft drinks and alcohol are subjected to hydrophilic treatment, and oil samples such as vegetable oil and industrial oil are subjected to water repellent treatment.

  In the case of hydrophilic treatment, super-hydrophilization by plasma treatment, super-hydrophilization by sol-gel method, super-hydrophilization by photocatalyst, super-hydrophilization by additives, super-hydrophilic treatment by inorganic nanoparticle coating, hot water treatment of gel film Techniques such as hydrophilization by graft copolymerization, hydrophilization by hydrophilic micelle crosslinking, hydrophilization by corona discharge, hydrophilization by laser irradiation, and hydrochloric acid treatment can be used.

  In addition, water repellency treatment includes super water repellency by plasma treatment, super water repellency by fluorine surface modifier, super water repellency by chemical adsorption method, super water repellency by sol-gel method, fluorine Super water-repellent treatment by electrodeposition coating with a fluorine-based graft copolymer / fluorine resin fine particles, water repellency by a silane coupling agent, water repellency by an acrylic silicone / silica composite film, water repellency by a chemical adsorption monomolecular film , Coating with chemicals with functional groups such as super water repellency by ion beam modification and saturated fluoroalkyl group (especially trifluoromethyl group), alkylsilyl group, fluoroacyl group, long chain alkyl group There is a technique such as, and it can be selected and used corresponding to each sample.

  An opening 4 for connecting a sample supply pipe 3 for supplying a sample liquid to the pipe 1 and an opening 6 for connecting a purge gas discharge pipe 5 to the pipe 1 are provided at the upper end of the pipe 1. Further, at the lower end of the pipe 1, an opening 8 for connecting a purge gas supply pipe 7 provided with a pressure controller 30 to the pipe 1 and an opening 10 for connecting a discharge pipe 9 for discharging a sample liquid to the pipe 1. Is provided.

  A purge gas such as helium is sent from below through the gas supply pipe 7 and the opening 8 to the gas-liquid contact extractor 2 in which the openings 4, 6, 8, and 10 are formed, and the sample supply pipe 3 and the opening are opened from above. Through 4, the sample liquid is dropped. Therefore, the gas (purge gas) and the liquid (sample liquid) are brought into contact with each other by countercurrent, and the analyte present in the liquid phase is rapidly moved to the gas phase.

  The sample supply pipe 3 communicates with the syringe pump 11, and a predetermined amount of sample liquid calibrated by the syringe pump 11 is supplied to the gas-liquid contact extractor 2 via the selector valve 31 and the sample supply pipe 3. A preheat pipe 12 is installed in the sample supply pipe 3. The gas supply pipe 7 is also provided with a preheat pipe 13. The gas-liquid contact extractor 2 is installed in the oven 14 and is temperature-controlled.

  The purge gas discharge pipe 5 communicates with a valve 15, and the valve 15 is connected to a vent 16 and a second valve 17. The valve 17 is provided with connection paths 19 and 20 to the GC or GC / MS 18, a vent 21, and connection paths 23 and 24 to the concentration tube 22. Further, a heater 25 and a fan 26 are installed opposite to the concentration tube 22.

  A connecting pipe 28 is connected to the valve 15, and the connecting pipe 28 is connected to the gas supply pipe 7 through a needle valve 27. A predetermined number of sample tanks 32 are connected to the syringe pump 11 via a line 30 and a selector valve 31.

  The automatic liquid sample supply device 100 is preferably configured to include a gas-liquid contact extraction device. The gas-liquid contact extraction device includes the gas-liquid contact extractor 2, a discharge pipe 9 that discharges the sample liquid, and a liquid reservoir 34. The liquid reservoir 34 is a mechanism for maintaining a constant liquid level in order to prevent the purge gas from flowing out from the discharge pipe 9 connected to the lower part of the gas-liquid contact extractor 2. The liquid reservoir 34 is provided in the discharge pipe 9. The liquid reservoir 34 employs a mechanism using the principle of a U-tube manometer, for example, a U-tube structure or a structure in which a part of the sample liquid flowing out from the discharge tube 9 is formed in a large diameter. I can do it.

  As the liquid reservoir 34, a pipe is connected to the opening 10 of the gas-liquid contact extractor 2 or the discharge pipe 9 for discharging the sample liquid instead of a manometer, and a liquid level sensor and a solenoid valve (not shown) are connected here. The sample liquid that is provided and discharged may be configured to maintain a constant liquid level in the pipe. Further, a load corresponding to a water column may be applied to the discharge portion of the U-shaped tube so that the sample liquid can maintain the water surface in the pipe.

  Hereinafter, the operation of the gas-liquid contact extractor 2, the gas-liquid contact extraction device 200, and the automatic liquid sample supply device 100 will be described. The sample liquid is supplied to the gas-liquid contact extractor 2 by the syringe pump 11 through the selector valve 31 and the sample supply pipe 3. The sample liquid is heated to the sample extraction temperature by the preheat pipe 12 in the sample supply pipe 3 in order to achieve a rapid gas-liquid equilibrium state in the gas-liquid contact extractor 2.

  The flow path of the entire system, in particular, the oven 14 in which the gas-liquid contact extractor 2 is housed and the flow path between the oven 14 and the GC or GC / MS 18 are temperature-controlled so that the temperature is equal to or higher than the sample extraction temperature. It is good to set. By such temperature setting, it is possible to prevent water vapor condensation and analyte adsorption caused by the following purge.

  The container 32 is a container containing a sample liquid, and containers containing different sample liquids can be installed in parallel and connected to the selector valve 31 respectively. The container 33 is a container containing a standard sample liquid having a known concentration of analytical species, and the container 35 is a container containing cleaning water.

  Next, an operation in which the automatic liquid sample supply apparatus 100 supplies the sample liquid to the gas-liquid contact extractor 2 will be described. First, the selector valve 31 is operated to open the port a connected to the container 32 containing the sample liquid. Next, the valve 29-1 moves to a position connecting the port b and the port c, and the valve 29-2 moves to a position connecting the port a and the port b. Thereby, the container 32 containing the sample liquid and the pipe 30 are connected, and the sample liquid can be sucked by the syringe pump 11-1 and the syringe pump 11-2.

  After the sample liquid is aspirated by the syringe pump 11-1 and the syringe pump 11-2, the syringe pump 11-1 moves to a position connecting the port a and the port b of the valve 29-1, and the sample liquid is gas-liquid through the pipe 3. Feed to contact extractor 2. At this time, the syringe pump 11-2 stops the sample liquid supply operation. Before the sample liquid supplied by the syringe pump 11-1 runs out, the valve 29-1 moves to a position connecting the port b and the port c and sucks the sample liquid again.

  While the sample liquid is being sucked by the syringe pump 11-1, the sample liquid sucked by the syringe pump 11-2 is removed from the pipe 3 by moving to a position where the port b and the port c of the valve 29-2 are connected. The liquid contact extractor 2 is supplied.

  As described above, the sample liquid is continuously supplied to the gas-liquid contact extractor 2 by interlocking the syringe pump 11-1 with the valve 29-1, and the syringe pump 11-2 with the valve 29-2.

  The liquid sample warmed in the sample supply tube 3 and adapted to the extraction temperature always enters the gas-liquid contact extractor 2 through the opening 4 and flows down along the bottom surface of the tube 1 installed in an oblique shape. On the other hand, the purge gas is supplied to the gas-liquid contact extractor 2 at a constant flow rate, warmed to an appropriate temperature by the preheat pipe 13 in the gas supply pipe 7, and continuously enters the gas-liquid contact extractor 2 through the lower opening 8 and rises. To do. Therefore, the sample liquid and the purge gas are always in countercurrent and contact with each other.

  The flow rate of the sample liquid is 0.01 to 5 ml / min, the purge gas flow rate is 0.1 to 100 ml / min, and the extraction temperature is within the range in which the liquid sample is not frozen and the target analyte is not thermally decomposed. The extraction is performed at a temperature suitable for extraction, and the extraction time is set according to the liquid sample.

  The liquid phase and the gas phase heated in the gas-liquid contact extractor 2 are constantly subjected to mass transfer at the boundary. What is required here is an improvement in the contact efficiency between the gas and the liquid, and the rapid movement of the substance in the liquid, that is, the analyte, into the gas phase by the gas-liquid contact.

  The sample liquid is always discharged from the gas-liquid contact extractor 2 to which the sample liquid is supplied at a constant flow rate via the liquid reservoir 34 utilizing the principle of the U-tube manometer. Outflow from the liquid reservoir 34 is prevented, and supply of purge gas at a constant flow rate is ensured in the concentration tube 22 for concentrating the gas-liquid extracted analyte. The purge gas pressure is adjusted to a pressure necessary to supply the purge gas containing the extracted analyte at a constant flow rate to the concentrating tube 22.

The sample liquid stored in and discharged from the liquid reservoir 34 prevents the purge gas from flowing out from the lower part of the gas-liquid contact extractor 2 and maintains the supply pressure of the purge gas. As a result, a stable supply of the gas phase in the gas-liquid contact extractor 2 is performed, and a balance with the sample liquid supply can be achieved. As a result, gas-liquid contact is sufficiently performed, contributing to gas-liquid equilibrium.

  The most important is a rapid approach to vapor-liquid equilibrium near the opening 6 connecting the purge gas discharge pipe 5. The gas phase and liquid phase flow and mass transfer of the analyte due to countercurrent contact are schematically shown in FIG. According to the flow of the sample liquid due to the mass transfer between the gas phase and the liquid phase described above, the analyte is efficiently moved into the gas phase, and the analyte concentration in the liquid phase is the smallest at the liquid phase outlet 10. The concentration of the analyte in the gas phase becomes maximum near the opening 6.

  In Table 2 of Example 1 below, theoretical values and experimental values are shown for the conventional P & T method and the present invention. The theoretical value and the experimental value of the conventional P & T method are greatly different from each other, and the mass transfer of the analyte to the gas phase is not sufficiently performed. In the present invention, the theoretical value and the experimental value coincide with each other. It was found that gas-liquid equilibrium was reached in the vicinity.

In the gas-liquid contact extractor 2, assuming that the gas-liquid equilibrium state is achieved at the outlet opening 6 connecting the purge gas discharge pipe 5, the gas-liquid contact extractor 2 moves to the gas phase portion based on the above equation 2 that defines the distribution coefficient. The amount of analytical species can be calculated. The distribution coefficient is expressed by Equation 2, and if K = 1, the concentration of the sample compound in the liquid phase (g / cm ³ ) and the concentration of the sample compound in the gas phase (g / cm ³ ) ”means equal. That is, in Table 1 above, the compound having K = 1 or more has a larger amount in the liquid phase than in the gas phase. In this application, “whether the distribution coefficient is large or small” means “whether K = 1 or larger”.

  In the gas-liquid contact extractor 2, it is important to reduce the thickness of the liquid phase in order to efficiently approach the theoretical gas phase concentration based on the gas-liquid equilibrium as much as possible. The thickness of this liquid phase is formed thin as described above due to the wettability of the inner surface of the tube 1 constituting the gas-liquid contact extractor 2.

Mass transfer in the liquid phase is governed by the diffusion coefficient. And it is known that the diffusion coefficient of the molecule | numerator in water is about 10 ^<-5 > cm < ² > / sec order. And as the thickness of the liquid phase is thinner, the time for the moving substance, that is, the analyte to reach the gas-liquid boundary surface is earlier, and the number of times that the analyte in the liquid phase contacts the gas phase increases. That is, the thinner the liquid phase, the greater the amount of analyte that moves to the gas phase, which means that the time to reach the vapor-liquid equilibrium state is shorter.

Considering benzene in a liquid phase with a flow thickness (depth) of 220 μm, the diffusion coefficient of benzene in water is 1.02 × 10 ⁻⁵ cm ² / sec. In water, one molecule of benzene will be present somewhere within the range of 18 μm after 1 second. Assuming that the thickness of the liquid phase is 0.22 mm (220 μm), the time to reach the liquid surface from the bottom is approximately 10 seconds (12.2 seconds in calculation). In addition, when the pipe 1 falls for 30 seconds at a water flow rate of 2 ml / min, the benzene molecule can reach the gas-liquid contact surface twice, and the benzene molecule has two chances to move to the gas phase. Will be.

  The flow of liquid and the thickness of the water channel in the pipe 1 can be analyzed by the speed theory of the open channel. When the shape of the tube 1 is spiral, the mixing effect (displacement of lower and upper water) of the fluid is promoted by the generation of the secondary flow, and the driving force for causing efficient mass transfer from the liquid phase to the gas phase It has become.

  Further, the gas-liquid contact extractor 2 may be a box-type water channel having a flat bottom surface, and has a flow path through which the sample liquid flows from the upstream and purge gas can be introduced from the downstream, and the introduced purge gas is captured. The tube shape is not limited to the above as long as it is not discharged to any place other than the collecting tube.

  In the present invention, the distribution coefficient K can be reduced by preheating the sample liquid, and the liquid phase is formed thin due to the wettability of the inner surface of the tube 1, so that the analysis species into the gas phase can be reduced. Mass transfer was fast and purge efficiency increased. As a result, the analyte concentration (theoretical value) in the gas phase theoretically calculated based on the definition of the distribution coefficient (Equation 2) is substantially the same as the analyte concentration (experimental value) obtained in the actual experiment. It has become.

  The sample water containing 2-MIB and Geosimin was analyzed by the conventional P & T method and the gas-liquid contact extraction method of the present invention using the system including the gas-liquid contact extraction device of the present invention and the automatic liquid sample supply device shown in FIG. . An experimental example for comparing the amount of mass transfer of 2-MIB and Geosimin into the gas phase is shown.

  Table 2 shows the theoretical mass transfer amounts of 2-MIB and Geosimin that move from the liquid phase of the concentration 5ppt (5 pg / mL) to the gas phase, and the respective extraction for the conventional P & T method and the gas-liquid contact extraction method of the present invention. Shows efficiency. The amount of sample water in the conventional P & T method is 20 ml, and in the method of the present invention, water is passed for 20 minutes at a water flow rate of 2 ml / min, so the total amount is 40 ml.

  In the conventional P & T method, the theoretical mass transfer amount to the gas phase is from formula 1 to 2-MIB: 72.0 pg, Geosimin: 76.3 pg, and the experimental values are 2-MIB: 44.6 pg, Geosimin: 59. It was 9 pg. The experimental value is far below the theoretical value. This means that mass transfer from the liquid phase to the gas phase by the conventional P & T method is not performed rapidly, and the vapor-liquid equilibrium state has not been reached.

  On the other hand, the theoretical mass transfer amount to the gas phase of the method of the present invention is from formula 2 to 2-MIB: 132.1 pg, Geosimin: 150.0 pg, and the experimental values are 2-MIB: 139.6 pg, Geosimin: It was 157.2 pg. The experimental and theoretical values were almost equal. This means that the mass transfer from the liquid phase to the gas phase according to the method of the present invention is performed rapidly, and a vapor-liquid equilibrium state is reached at the purge gas outlet.

  The “spiral tube (counterflow) method” based on the principle of gas-liquid countercurrent contact extraction of the present invention has been found to be a method that can obtain the extraction efficiency as theoretically. Furthermore, the method of the present invention extends the gas-liquid countercurrent contact extraction operation time, so that it can be concentrated as long as it does not exceed the breakthrough capacity of the adsorbent for the analyte, so detection sensitivity is improved in GC and GC / MS analysis. it can.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water: Conventional P & T: 20 ml, method flow rate of the present invention: 2 ml / min
3) Purge gas flow rate: Conventional P & T: 80 ml / min (120 kPa), method flow rate of the present invention: 80 ml / min (120 kPa)
4) Extraction time: 20 min
5) Sample flow path temperature: 60 ° C
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCl was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 ° C. (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: 2-MIB: m / z 95, 107, Geosimin: m / z 112, 125

In the gas-liquid contact extraction method of the present invention using the automatic liquid sample supply device of the present invention, the extraction efficiency of 2-MIB and Geosimin was compared by changing the purge gas flow rate and the sample water flow rate. The extraction efficiency conditions for 2-MIB and Geosimin due to differences in purge gas flow rate and sample water flow rate are:
A: Sample water flow rate: 4 ml / min, purge gas flow rate: 160 ml / min, extraction time: 10 minutes B: sample water flow rate: 2 ml / min, purge gas flow rate: 80 ml / min, extraction time: 20 minutes C: sample water flow rate: 1 ml / min, purge gas flow rate: 40 ml / min, extraction time: 40 minutes, and extraction temperature was 60 ° C. The results are shown in FIG. It was found that the condition for obtaining high extraction efficiency for both components was B in the figure.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 1, 2, 4 ml / min
3) Purge gas flow rate: 40 ml / min (60 kPa), 80 ml / min (120 kPa),
160mlmin (240kPa)
4) Sample flow path temperature: 60 ° C min
5) Extraction time: 10, 20, 40 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 degrees Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCL is sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: 2-MIB: m / z 95, 107, Geosimin: m / z 112, 125

  Experiments were conducted on the analysis reproducibility of 2-MIB and Geosimin by the system including the gas-liquid contact extraction device of the present invention and the automatic liquid sample supply device shown in FIG. 2-MIB and Geosimin are known as causative odor causative substances in tap water, but the water quality standard item was set to a low standard value of 0.01 μg / L (10 ppt) as a result of the April 2004 water supply law revision. As the lower limit of quantification, an extremely low value of 0.001 μg / L (1 ppt), which is 1/10 of the lower limit, is required. The olfactory threshold is described in the Ministry of the Environment's “Smell Measurement Method Manual”.

  Repeated reproducibility tests were conducted at a concentration of 1 ppt each of 2-MIB and Geosimin. The results are shown in FIG. 4, FIG. 5, and FIG. Further, the CV (%) was calculated for the peak area values of 2-MIB and Geosimin when measured three times. Good results shown in Table 3 were obtained.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 2 ml / min
3) Purge gas flow rate: 80 ml / min (120 kPa)
4) Sample flow path temperature: 60 ° C
5) Extraction time: 20 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCl was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: 2-MIB: m / z 95, 107, Geosimin: m / z 112, 125

The gas-liquid contact extraction method of the present invention using the system including the gas-liquid contact extraction device of the present invention and the automatic liquid sample supply device shown in FIG. 1 is performed, and the uniformity of the extraction time due to the difference in sample concentration between 2-MIB and Geosimin ( Experiments on linearity). FIG. 7 shows mass chromatograms at concentrations of 0.5 ppt, 1 ppt, 5 ppt, 10 ppt, 50 ppt, and 100 ppt for linearity at a concentration of 0.5 to 100 ppt. This experiment was repeated three times, and the results of plotting the average value on the vertical axis and the concentration on the horizontal axis are shown in FIGS. Both 2-MIB and Geosimin had good linearity of R ² = 0.999 or more.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 2 ml / min
3) Purge gas flow rate: 80 ml / min (120 kPa)
4) Sample flow path temperature: 60 ° C
5) Extraction time: 20 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCl was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: 2-MIB: m / z 95, 107, Geosimin: m / z 112, 125

2,4,6-Trichloroanisole (hereinafter TCA) has a very small olfactory sense and is said to be 30 ppq. This compound is a causative substance of mold odor and detoxifies 2,4,6-trichlorophenol (hereinafter referred to as “TCP”), which is an antifungal agent for wood, by O-methylation of some molds. Became widely known as occurring during the breeding process.
In addition to TCP contamination of wood, it has been reported that TCA contamination occurs during chlorination of raw water or during transport using a water distribution system. In this way, there is a need for thorough management not only in water sources but also in manufacturing factories that handle water.

  Therefore, 2,4,6-trichloroanisole with a concentration of 30 ppq was prepared, and analysis was performed using the same gas-liquid contact extraction method as in Example 1 above with a sample flow rate of 2 ml / min and extraction time of 100 minutes (total flow rate of 200 ml). . MS was measured in SIM mode, and monitor ions were set to m / z 210 and 212. Other analysis conditions are the same as in Example 1.

  The analysis results are shown in FIG. Since there has been no report example of analyzing 30 ppq TCA in the past, this example is a result demonstrating the high extraction efficiency of the present invention.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 2 ml / min
3) Purge gas flow rate: 80 ml / min (120 kPa)
4) Sample flow path temperature: 60 ° C
5) Extraction time: 20 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCl was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mm D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: TCA: m / z 210, 212

  On November 30, 2009, 1,4-dioxane was added to the environmental standards related to the protection of human health related to water pollution in public water bodies and the environmental standards related to water pollution in groundwater. The environmental standard is 0.05 mg / L or less, and the groundwater environmental standard is 0.05 mg / L or less. In addition, due to the addition of environmental standards and groundwater standards, the establishment of drainage standards is currently under deliberation by the Central Council Water Environment Subcommittee, etc. It is. In addition, in the revised Water Supply Law (April 22, 2003, Ministry of Health, Labor and Welfare Notification No. 261) that has been in force since April 2004, the standard value for tap water for 1,4-dioxane is also 0.05 mg / L. In the water supply law, the lower limit of detection is required to be 1/10 or less of the reference value.

  The analysis method of 1,4-dioxane in the water supply method is a solid phase extraction / solvent extraction-GC / MS method. In the gas-liquid contact extraction method of the present invention, 1 / 4-dioxane 0.05 mg / L 1 / 10 μg / L (5 ppb) was examined. MS under measurement conditions was measured in SIM mode, and monitor ions were set to m / z 58 and 64. The other conditions were the analysis conditions described in Example 1.

  The results are shown in FIG. The peak is tailing because the column liquid phase of the used capillary column is slightly polar and the film thickness is 0.25 μm. In general, GC analysis of 1,4-dioxane uses a medium polarity and a film thickness of about 2 μm. Although it is necessary to optimize the column, the results show that 1,4-dioxane can be analyzed by the gas-liquid contact extraction method of the present invention.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 2 ml / min
3) Purge gas flow rate: 80 ml / min (120 kPa)
4) Sample channel temperature: 60 ° C)
5) Extraction time: 20 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCl was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 ° C. (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: 1, 4 Dioxan: m / z 58, 64

Analysis of volatile organic compounds in sesame oil Sesame oil is produced by a process of roasting and pressing at a high temperature. At this time, sugar and protein in the component cause a Maillard reaction to generate a pyrazine compound that is an aroma component. These pyrazines have been proposed to exhibit physiological activity, and there are many research reports.

  An example of analyzing volatile organic compounds in sesame oil by the gas-liquid contact extraction method of the present invention is reported with reference to FIG. As a result of analysis, methylpyrazole, dimethylpyrazole, and ethylpyrazole, which are nitrogen-containing compounds, were detected.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 2 ml / min
3) Purge gas flow rate: 80 ml / min (120 kPa)
4) Sample flow path temperature: 60 ° C
5) Extraction time: 20 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 degrees Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: After activating hydroxyl groups on the glass surface, a toluene solution in which octadecyldimethylchlorosilane was dissolved Put it in, reflux for a predetermined time, wash with toluene and dry. Thereby, the chemical modification of the octadecyl group on the glass surface was carried out, and the hydrophobicity of the glass surface was improved.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap Pure-WAX, 0.25 mm I.D. D. x30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) Scan mode: m / z 10-450

  In the gas-liquid contact extraction method of the present invention using the automatic liquid sample supply device of the present invention, an analysis was performed comparing the case of “with preheat tube” and the case of “without preheat tube”. The analysis results are shown in FIGS. It can be seen that without the preheat tube, the distribution coefficient of the analyte increases and the amount of mass transfer to the gas phase decreases.

<Experimental conditions>
(1) Sample water extraction conditions 1) Sample water extraction temperature: 60 ° C
2) Sample water flow rate: 2 ml / min
3) Purge gas flow rate: 80 ml / min (120 kPa)
4) Sample flow path temperature: 60 ° C
5) Extraction time: 20 min
6) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 7) Spiral tube inner surface treatment: 18% HCl was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 200 mg (collection tube 3.2 mm ID × 200 mm)
2) Collection temperature: 60 ° C
3) Collection tube heating temperature: 220 (10 minutes)
4) Desorption flow rate during heating: 11 ml / min
5) Valve temperature: 150 ° C
6) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature during sample introduction: 220 ° C. (5 ° C./second), (holding time 10 min)
3) Analytical column flow rate: 1 ml / min
4) Split flow rate: 10 ml / min
5) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
6) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 0.25μm
7) Ion source: EI, 70 eV
8) SIM mode: 2-MIB: m / z 95, 107, Geosimin: m / z 112, 125

  In the conventional P & T method, the turbidity of the river water is clogged with frit, and the river water cannot be analyzed. However, the river water can be analyzed by the gas-liquid contact extraction method of the present invention. As a result, the river water online musty odor continuous monitoring at regular times can be implemented.

  River water whose turbidity increased during rainy weather was sampled, and the mold odor (2-methylisoborneol and Geosmin) was measured by the gas-liquid contact extraction method of the present invention.

  FIG. 15 shows SIM chromatograms (18.3-20 · 3 min: m / z 95, 20.3) for a 10 ppt mold odor standard water (a) and a river water (b) with a turbidity of 150 degrees (kaolin). -22.5 min: m / z 112). In the SIM chromatogram of (a), peak 1 is 2-MIB and peak 2 is Geosmin. In the SIM chromatogram of (b), many contaminant components were confirmed around the peaks of 2-MIB and Geosmin due to the influence of contaminant components, and the rise in baseline was also remarkable. It turns out that analysis of river water is possible enough.

<Experimental conditions>
(1) High turbidity river water extraction conditions 1) Extraction temperature: 60 ° C
2) Flow rate: 2 mL / min
3) Purge gas flow rate: 80 mL / min
4) Extraction time: 2.5 min
5) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 6) Spiral tube inner surface treatment: 18% HCL was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 50 mg (collection tube 3.2 mm ID × 300 mm)
2) Collection tube temperature during sampling: 60 ° C
2) Collection tube heating temperature: 220 ° C. (5 ° C./sec, 10 minutes)
3) Desorption flow rate during heating: 2.4 mL / min
4) Valve temperature: 150 ° C
5) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Analytical column flow rate: 2.4 mL / min
2) Split flow rate: 0 mL / min (splitless)
3) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
4) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 1.0μm
5) Ion source: EI, 70 eV
6) SIM mode: 2-MIB: m / z 95, 107, Geosimin: m / z 112, 125

  Tea contains a lot of substances called saponins, and these have high foaming properties, and in the conventional P & T method, bubbles are blown up together with the purge gas and enter the collecting tube, making it impossible to analyze tea.

  However, tea can be analyzed by the gas-liquid contact extraction method of the present invention. Accordingly, FIG. 16 shows a total ion current chromatogram (hereinafter abbreviated as TICC) in which a commercially available tea beverage was compared with respect to aroma components immediately after opening and after 10 days.

  Sample (a) 10 days after opening contains 1-octen-3-ol of peak 1 and 2-Heptenal, (E)-of peak 2 which are off-flavor components not detected immediately after opening (b). Remarkably confirmed. It was also found that the flavor component 1,6,10-Dodecatrien-3-ol, 3,7,11-trimethyl- (also known as nerolidol) of the peak 4 detected immediately after opening was not detected after 10 days. Both (5E) -3,4-dimethyl-5-pentylidenefuran-2-one (also called boride) of peak 3 were confirmed. It was proved that tea can be analyzed by the gas-liquid contact extraction method of the present invention.

<Experimental conditions>
(1) Commercial tea beverage extraction conditions 1) Extraction temperature: 40 ° C
2) Flow rate: 2 mL / min
3) Purge gas flow rate: 60 mL / min
4) Extraction time: 10 min
5) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 6) Spiral tube inner surface treatment: 18% HCL was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 100 mg (collection tube 3.2 mm ID × 300 mm)
2) Collection tube temperature during sampling: 40 ° C
3) Collection tube heating temperature: 220 ° C. (5 ° C./sec, 10 minutes)
4) Valve temperature: 150 ° C
5) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Analytical column flow rate: 1 mL / min
2) Split flow rate: 5 mL / min
3) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
4) Capillary column: InertCap 5MS / Sil, 0.25 mmI. D. × 30m, df = 1.0μm
5) Ion source: EI, 70 eV
6) Scan mode: m / z 15-450

  Milk has high foaming properties due to casein protein and whey protein, and in the conventional PT method, foam is blown up together with purge gas and enters the collection tube, making it impossible to analyze milk.

  However, milk can be analyzed by the gas-liquid contact extraction method of the present invention. Therefore, the present invention was analyzed for volatile organic compounds in commercial milk. TICC is shown in the chromatogram of FIG.

  As a result of library search, acetone, 2-butanone, ethyl acetate, 4-methyl-2-pentanone, pentanal, DMDS, hexanal, heptan-2-one, nonan-2-one and the like were confirmed. It was proved that milk can be analyzed by the gas-liquid contact extraction method of the present invention.

<Experimental conditions>
(1) Commercial milk extraction conditions 1) Extraction temperature: 40 ° C
2) Flow rate: 2 mL / min
3) Purge gas flow rate: 60 mL / min
4) Extraction time: 10 min
5) Spiral tube shape: inner diameter 4 mm, length 1200 mm, installation angle 30 ° Pyrex (registered trademark) glass 6) Spiral tube inner surface treatment: 18% HCL was sealed in a spiral tube, washed and dried. As a result, the glass surface was decontaminated and the silanol groups on the glass surface were activated to improve the hydrophilicity of the glass surface.
(2) Sample concentration condition 1) Collection agent: Tenax TA 100 mg (collection tube 3.2 mm ID × 300 mm)
2) Collection tube temperature during sampling: 40 ° C
3) Collection tube heating temperature: 220 ° C. (5 ° C./sec, 10 minutes)
4) Valve temperature: 150 ° C
5) Transfer line temperature: 150 ° C
(3) GCMS measurement conditions 1) Analytical column flow rate: 1 mL / min
2) Split flow rate: 5 mL / min
3) GC oven temperature: 40 ° C. (12 min) −20 ° C./min−250° C. (5 min)
4) Capillary column: InertCap AQUATIC-2, 0.25 mm I.D. D. x40m, df = 1.4μm
5) Ion source: EI, 70 eV
6) Scan mode: m / z 15-450

  According to the present invention, it has become possible to easily analyze an analyte having a large partition coefficient, an analyte having a high water solubility, or an analyte having a low olfactory threshold, which has been difficult in the past. In addition, in quality control of tap water, river water, and beverages, it has become possible to introduce samples unattended from sampling to extraction and analysis continuously for a long time without manual operation.

Claims (8)

  A gas-liquid contact extraction method that uses a gas-liquid contact extractor that continuously introduces a sample liquid from above and a purge gas from below, makes the sample liquid and purge gas contact each other, and extracts an analyte in the sample liquid. The gas liquid is discharged through the liquid reservoir provided in the discharge pipe connected to the lower part of the gas-liquid contact extractor, and the purge gas is prevented from flowing out of the liquid reservoir. Liquid contact extraction method.   The gas-liquid contact extraction method according to claim 1, wherein the sample liquid is preheated to an extraction temperature in the gas-liquid contact extractor before supplying the sample liquid to the gas-liquid contact extractor.   3. A gas-liquid contact extraction of a water-soluble component having a partition coefficient K greater than 1 or an analyte present in a liquid having an olfactory threshold lower than 10 ppt (pg / ml). Liquid contact extraction method.   The gas-liquid contact extractor is installed in a temperature-controllable oven, and the flow path to the collection tube where the analytes extracted by gas-liquid contact extraction are concentrated is the same as or higher than the oven temperature (gas-liquid extraction temperature) The gas-liquid contact extraction method according to any one of claims 1 to 3, wherein an analytical species extracted by gas-liquid extraction is concentrated in a collection tube at a higher temperature.   A gas-liquid contact extractor that supplies a liquid sample from above and a purge gas from below is provided. A discharge pipe is connected to the lower part of the gas-liquid contact extractor, and the purge gas is discharged into the discharge pipe while discharging the sample liquid. A gas-liquid contact extraction device comprising a liquid reservoir for preventing discharge.   6. The gas-liquid contact extraction device according to claim 5, wherein the contact surface with the sample liquid of the gas-liquid contact extractor is subjected to a surface treatment so that the contact surface is in an expanded wet state.   The gas-liquid contact extraction device according to claim 6, wherein the surface treatment is either a hydrophilic treatment or a water repellent treatment.   A liquid sample supply unit is connected to the gas-liquid contact extraction device according to any one of claims 5 to 7 via a syringe pump and a selector valve for switching a flow path, and the gas-liquid contact extraction device An automatic liquid sample supply device for sending an analytical species extracted by gas-liquid contact to a collection tube.

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