JP2007178184A - High sensitivity quantitative analyzing method of 3-methyl-2-butene-1-thiol in fermented malt beverage or beer-like beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an analyzing method capable of quantitatively analyzing 3-methyl-2-butene-1-thiol (3MBT) being a causative substance of a solar ray smell in a concentration region, which is lower than an organoleptic threshold and further lower than before, with sufficient sensitivity and high precision. <P>SOLUTION: An inert gas is blown in a fermented malt beverage or a beer-like beverage and a very small amount of a volatile component is expelled from the beverage to be collected in the collector in a collection pipe while the obtained collected component is passed through a heating desorbing device, a cryofocus trap and a capillary gas chromatoculmn to be detected using a mass analyzer. In the high sensitivity quantitative analyzing method of 3MBT being the solar ray smell component in the fermented malt beverage or the beer-like beverage, a combination of at least two kinds of collection pipes is used as the collection pipe and/or a stable isotope of 3MBT is used as an internal standard substance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

Background of the Invention

FIELD OF THE INVENTION The present invention relates to a highly sensitive quantitative analysis method for 3-methyl-2-butene-1-thiol, which is a sunlight odor component in fermented malt beverages or beer-like beverages.

Background Art 3-Methyl-2-butene-1-thiol (hereinafter sometimes referred to as “3MBT”) is known as a causative substance of “sunlight smell” of beer. “Sunlight odor” refers to a strange odor that is generated when beer is exposed to sunlight or fluorescent light for a long time. The precursor of 3MBT is hop isoalpha acid (a bitter component), and the side chain of this isoalpha acid is cleaved at a wavelength of 520 nm or less, and binds to SH radicals generated from sulfur-containing amino acids to form thiol compounds. Generate. This is 3MBT. Although the mechanism of 3MBT production has not yet been fully elucidated, it is known that a small amount of 3MBT is produced even during the production process of beer.

  Since 3MBT has a very low functional threshold concentration (for example, 4 to 35 ppt) and is highly reactive, it was difficult to accurately analyze 3MBT below the functional threshold concentration.

  For example, in J. Am. Soc. Brew. Chem., 1991, 49 (4), pp162-165 (Non-Patent Document 1), 3 MBT in beer is collected in a collecting agent, and then gas chromatogram method and A method of quantifying 3 MBT using a combination of a flame photometric detector (FPD) detector has been reported. However, this method is not necessarily sufficient for quantitative analysis of 3MBT below the sensory threshold concentration.

  In J. Am. Soc. Brew. Chem., 1993, 51 (2), pp70-74 (Non-Patent Document 2), 3MBT is collected in Hg (II) cyanide and then extracted into an organic solvent. It has been reported that 3MBT below the sensory threshold concentration (1 ppt or less) could be detected by using this in combination with a gas chromatogram method and a mass spectrometer. Here, 1-hexanethiol is used as an internal standard substance. However, although this method is sufficient in sensitivity compared with the previous technology, the operation is complicated, and quantitative analysis of 3MBT with a very small amount of high reactivity can be performed accurately and efficiently. It was not easy.

  Proceedings of the 29th EBC Congress Dublin 2003 (Non-patent Document 3) analyzed using sodium 4-hydroxymercury benzoate as a scavenger, and found that 0.4 ng / L (ppt) of beer It has been reported that 3MBT could be quantified. However, this method is complicated in operation and is undesirable from the viewpoint of safety because it uses mercury.

  In Japanese Patent No. 3390695 (Patent Document 1), 10 to 50 wt% (preferably 20 to 40 wt%) of graphite carbon and 90 to 50 of poly (2,6-diphenyl-p-phenylene oxide) are used as a scavenger. Use a composition consisting of wt% (preferably 80-60 wt%) and / or beer temperature when blowing inert gas into beer −5 ° C.-10 ° C. (preferably −2 ° C.- It is disclosed that 3MBT below the sensory threshold concentration could be detected by setting the temperature to 5 ° C. It is also disclosed that the detection limit of 3MBT by this method was 0.21 ppt in calculation, and 1-hexanethiol is used as an internal standard substance in the measurement. However, although this method is sufficient in sensitivity compared with the previous technology, since the stability of the state collected in the collection agent is poor, a very small amount of highly reactive 3MBT is accurately obtained. And it is not easy to perform quantitative analysis efficiently. That is, in order to obtain highly reliable data, it is desirable to perform repeated measurement on one sample about 2 to 5 times or more, and the operation tends to be complicated.

  For this reason, there is still a demand for a quantitative analysis method capable of quantitatively analyzing 3MBT with sufficient sensitivity in a concentration range lower than the sensory threshold concentration and even lower than the conventional concentration range. Yes.

Japanese Patent No. 3390695 J. Am. Soc. Brew. Chem., 1991, 49 (4), pp162-165 J. Am. Soc. Brew. Chem., 1993, 51 (2), pp70-74 Proceedings of the 29th EBC Congress Dublin 2003

Summary of the Invention

  The present inventors have recently used poly (2,6-diphenyl-p-phenylene oxide) as a scavenger when analyzing by combining the purge & trap method and gas chromatograph-mass spectrometry (GC / MS). By using a combination of two or more types of collection tubes that use sucrose, components that can generate measurement noise can be efficiently excluded from the sample, and lower-level 3MBT can be quantitatively analyzed with high accuracy. I found what I could do. Further, the present inventors have found that when 3MBT is quantitatively analyzed, by using a stable isotope of 3MBT as an internal standard substance, a lower level of 3MBT can be quantitatively analyzed with high accuracy. The present invention is based on these findings.

  Therefore, the present invention is capable of quantitatively analyzing 3MBT, which is a causative substance of sunlight odor, with sufficient sensitivity and high accuracy in a concentration range lower than the sensory threshold concentration and lower than the conventional concentration range. The purpose is to provide a method for analyzing 3MBT.

The highly sensitive quantitative analysis method of 3-methyl-2-butene-1-thiol which is a sunlight odor component in a fermented malt beverage or beer-like beverage according to the present invention blows an inert gas into the fermented malt beverage or beer-like beverage. The trace amount of volatile components are expelled from the beverage and collected by a collecting agent in a collecting tube, and the collected components are passed through a heat desorption device, a cryofocus trap, and a capillary gas chromatography column, and then massed. Which is detected using an analyzer,
As the collecting tube, a single collecting component in which the component in the collecting tube is composed of poly (2,6-diphenyl-p-phenylene oxide) (50 to 100% by weight) and graphite carbon (50 to 0% by weight). Use a collecting tube, or use a combination of two or more collecting tubes comprising poly (2,6-diphenyl-p-phenylene oxide) as a collecting agent in at least each collecting tube. And (1) The combination of the two or more types of collection tubes is a volatile component generated by heat desorption treatment of the first collection tube and the collection agent in the first collection tube. And at least one second collection tube arranged to collect, wherein at least one of the collection tubes captures measurement noise components such as ethanol, carbon dioxide, and water. It has a structure that keeps the collection efficiency low. That,
(2) using a stable isotope of 3-methyl-2-butene-1-thiol as an internal standard substance,
The method is carried out under either one or both conditions.

  According to the method of the present invention, a small amount of 3MBT that can be contained in a fermented malt beverage or a beer-like beverage (including a semi-finished product of the manufacturing process) is quantitatively analyzed with high accuracy even at a concentration below the sensory threshold. be able to. According to the method of the present invention, the lower limit concentration of the detection limit can be further lowered to a level of half or less compared to a conventionally known method (for example, the method described in Japanese Patent No. 3390695). As a result, such a low concentration of 3 MBT can be detected with high accuracy. Further, according to the present invention, at the time of analysis, there is no need to make the beverage temperature low (for example, a temperature lower than 0 ° C.) when the inert gas is blown into the beverage as the subject. Therefore, the method of the present invention can contribute to precise process control and quality control, and further helps to develop a hop processed product that hardly generates sunlight odor, establish process conditions, and develop a new container.

Detailed description of the invention

  As described above, the method according to the present invention is a highly sensitive quantitative analysis method for 3-methyl-2-butene-1-thiol, which is a sunlight odor component in a fermented malt beverage or beer-like beverage, An inert gas is blown into the beer-like beverage, a trace volatile component is expelled from the beverage and collected by a collection agent in a collection tube, and the obtained collection component is heated and desorbed by a desorption device, a cryofocus trap, And a method of detecting using a mass spectrometer after passing through a capillary gas chromatographic column, that is, a combination of purge & trap method and gas chromatograph-mass spectrometry (GC / MS) It is what.

In the present invention, “fermented malt beverage” refers to a beverage obtained by fermenting a raw material mainly composed of added hop wort obtained using malt, such as beer and sparkling liquor. It is done.
In addition, the “beer-like beverage” is a beverage other than the above-mentioned “fermented malt beverage”, and, similarly to the fermented malt beverage, a sunlight odor caused by 3-methyl-2-butene-1-thiol is generated by exposure to sunlight. Alternatively, any beverage that can increase, that is, a beverage that can contain 3MBT or a precursor thereof, is included. Examples of the “beer-like beverage” include fermented beverages made from grains having the same or similar flavor as beer. Specific examples include bean-derived ingredients such as soybeans and peas and hops. Examples include beverages obtained by fermentation as a raw material (including alcoholic beverages classified as “other miscellaneous sake 2” in the so-called liquor tax law).

  In addition, the “beverage” here includes not only a beverage as a product, but also a semi-finished product in the process of manufacturing the beverage, and 3MBT used for evaluating a beverage. Control solutions and the like are also included.

  Examples of the “inert gas” include nitrogen gas, helium gas, argon gas and the like, and preferable examples include high purity nitrogen gas.

  The purge and trap process in the present invention can be carried out in any conventional purge and trap apparatus. Therefore, in the present invention, a commercially available purge and trap apparatus can be used as appropriate. Further, the GC / MS method in the present invention can be carried out in any conventional GC / MS apparatus. Therefore, in the present invention, a commercially available GC / MS apparatus can be used as appropriate.

  According to a first aspect of the present invention, there is provided a method according to the present invention which is carried out under the condition (1). In other words, according to the first aspect of the present invention, there is provided a highly sensitive quantitative analysis method for 3MBT in a fermented malt beverage or beer-like beverage, wherein the analysis is performed by combining the purge & trap method and GC / MS, There is provided a method of using a combination of two or more types of collection tubes comprising poly (2,6-diphenyl-p-phenylene oxide) as a collection agent in at least each collection tube as a collection tube. The At this time, the combination of the two or more types of collection tubes collects the volatile components generated by heat desorption treatment of the first collection tube and the collection agent in the first collection tube. And at least one of the second collection tubes arranged so that at least one of the collection tubes has a collection efficiency for measurement noise components such as ethanol, carbon dioxide, and water. It has the structure which keeps low. According to a preferred embodiment, the first collection tube has a structure that suppresses the collection efficiency for measurement noise components such as ethanol, carbon dioxide, and water.

  Such a combination of two or more collecting tubes is further combined with a collecting tube such as the third, fourth, etc. as long as it includes these first and second collecting tubes. May be. Therefore, the 1st aspect of this invention includes the combination of the collection pipe | tube which arrange | positions a several collection pipe | tube in multiple stages in series as a collection agent. Preferably, the combination is a combination of two collecting tubes including a first collecting tube and a second collecting tube.

  In the present invention, components such as ethanol, carbon dioxide, and water are components that easily generate measurement noise in the GC / MS analysis stage. These measurement noise components can also be mixed in a trace volatile component obtained by purging and trapping. In the present invention, two or more kinds of collecting tubes are arranged in multiple stages as a collecting agent, and purge and trap processing is performed, so that these measurement noise components are moved to the stage before reaching the GC / MS apparatus. In addition, it can be eliminated efficiently. Furthermore, at this time, these measurement noise components can be used very efficiently by using a collection tube that has a structure that suppresses the collection efficiency of measurement noise components such as ethanol, carbon dioxide, and water. Can be eliminated.

  Here, the collection tube “has a structure that keeps the collection efficiency for the measurement noise component low” means that the collection capacity of the collection agent for 3 MBT and the measurement noise component, that is, affinity is focused. Although 3 MBT is collected, it means a state in which the composition ratio or arrangement of the collection agent in the collection tube is adjusted so that the measurement noise component is hardly collected. The constituent ratio or arrangement of the collection agent can be appropriately changed based on the contact amount of the trace volatile component passing through the collection tube per unit amount of the collection agent in the collection tube. Here, the contact amount can be defined, for example, as a value obtained by dividing the amount of volatile components passing through the collection tube (total amount per measurement) by the weight of the collection agent in the collection tube. This contact amount can represent the degree (opportunity) of contact between the volatile component passing through the collection tube and the collection agent in the collection tube.

  Poly (2,6-diphenyl-p-phenylene oxide), which is a collecting agent, is excellent in 3MBT collection efficiency. It was considered that the ability to collect 3MBT by this poly (2,6-diphenyl-p-phenylene oxide) was higher than the ability to collect measurement noise components. For this reason, by suppressing the contact amount of the volatile component passing through the collection tube, 3MBT is collected, but it is possible to create a state in which the measurement noise component is difficult to collect. As a means for keeping the contact amount low, for example, the ratio of the collecting agent among the components in the collecting tube is lowered, and instead a filler having substantially no collecting ability for 3MBT is used. It is done. Further, the volume of the collection tube itself may be reduced or the length thereof may be shortened.

  Therefore, as the “structure for suppressing the collection efficiency with respect to the measurement noise component” of the collection tube, preferably, the components in the collection tube are poly (2,6-diphenyl-p-phenylene oxide) and 3MBT. This is a case of a mixture composed of a filler having substantially no collecting ability. Here, the filler that does not substantially have the ability to collect 3MBT may be capable of collecting the measurement noise component as long as it does not substantially have the ability to collect 3MBT. , Those having no collection ability may be used. Further, “substantially has no collection ability” means that even if a desorption treatment is performed after the collection treatment, the target substance cannot be obtained to a level at which the object of the present invention can be analyzed. Examples of such a filler include glass beads and glass wool, and glass beads are preferable from the viewpoint of workability.

  Therefore, according to the preferable aspect of this invention, the component in the pipe | tube of a 1st collection pipe | tube consists of poly (2, 6- diphenyl-p-phenylene oxide) as a collection agent, and a glass bead.

  When using glass beads as a filler, the weight ratio of poly (2,6-diphenyl-p-phenylene oxide) and glass beads in the first collection tube is, for example, 10: 1 to 1:10, Preferably it is 8: 2 to 2: 8.

  According to one preferable aspect in the first aspect of the present invention, the first collecting tube is a micro-volatile component that passes through the collecting tube per unit amount of the collecting agent in the first collecting tube. It has a structure in which the contact amount of the components can be adjusted. Thereby, according to the conditions such as the type of fermented malt beverage or beer-like beverage that is the subject, the conditions of the measuring device, etc., a configuration that can efficiently eliminate the measurement noise component is appropriately selected in the first collection tube Is possible. For example, as described above, when the components in the first collection tube are composed of poly (2,6-diphenyl-p-phenylene oxide) as a collection agent and glass beads, the composition ratio is It is mentioned that the first collecting tube is provided in a structure that can be adjusted.

  According to another preferred embodiment of the first embodiment of the present invention, the weight percent of the collector poly (2,6-diphenyl-p-phenylene oxide) relative to all components in the first collector tube is: It is set to be smaller than the weight% of the collecting agent poly (2,6-diphenyl-p-phenylene oxide) with respect to all components in the second collecting tube. By adopting such a configuration, the collection efficiency with respect to the measurement noise component can be suppressed low in the first collection tube, the measurement noise component is eliminated, and the subsequent collection tube is more selective. It is possible to suitably collect 3MBT. Moreover, as a combination of the collection pipes used as the collection agent, when the number of stages of the collection pipes is 3 or more, the upstream collection pipe close to the purge process in the combination collection pipes. It is desirable to set so that the weight percent of the scavenger with respect to all components in the tube is reduced.

  In the first aspect of the present invention, the components in the second collection tube are preferably all composed of poly (2,6-diphenyl-p-phenylene oxide). In other words, 100% of the components in the second collection tube are preferably poly (2,6-diphenyl-p-phenylene oxide).

  Thus, according to a particularly preferred embodiment of the first embodiment of the present invention, the first collection tube contains poly (2,6-diphenyl-p-phenylene oxide) as a collection agent and glass beads. In the second collection tube, all the components in the tube are poly (2,6-diphenyl-p-phenylene oxide). By adopting such a configuration, 3MBT quantitative analysis with high accuracy and excellent detection limit can be performed.

  In the first aspect of the present invention, it is preferable to use an internal standard substance for the beverage to be tested during the purge and trap process. As an internal standard substance that can be used here, any substance that has similar physicochemical properties to 3MBT can be used as appropriate. For example, methylethyl mercaptan, 1-hexanethiol, 1-octanethiol, and 3MBT stability Isotopes and the like can be used. The amount of the internal standard substance used can be appropriately changed according to the amount of 3MBT contained in the beverage as the subject.

  According to a second aspect of the present invention, there is provided a method according to the present invention which is carried out under the condition (2). In other words, according to the second aspect of the present invention, there is provided a highly sensitive quantitative analysis method for 3MBT in a fermented malt beverage or beer-like beverage, wherein the analysis is performed by combining the purge & trap method and GC / MS, A method using a stable isotope of 3-methyl-2-butene-1-thiol as an internal standard substance is provided. By using a stable isotope of 3MBT as an internal standard substance, the method according to the present invention can perform quantitative analysis of 3MBT with excellent accuracy up to a lower detection limit than in the past. The use of a stable isotope of 3MBT as an internal standard substance is particularly effective when 3MBT in the subject is below the functional threshold concentration.

  In the second embodiment of the present invention, as the collecting agent, the components in the collecting tube are poly (2,6-diphenyl-p-phenylene oxide) (50 to 100% by weight) and graphite carbon (50 to 0). Or a poly (2,6-diphenyl-p-phenylene oxide) at least as a collecting agent in each collecting tube. Use a combination of the above collection tubes. Moreover, here, when a collection pipe | tube is a combination of 2 or more types of collection pipes, each collection pipe | tube is arrange | positioned in series and heat-desorbs the collection agent in the collection pipe located upstream. It is preferable that the following collection tube is arranged so that volatile components generated by the above can be collected.

  In the present invention, the “stable isotope of 3MBT” refers to one obtained by substituting at least one atom of an element constituting 3MBT with a stable isotope element of the element. Examples of such stable isotope elements include deuterium atom (D), tritium atom (T), C13, and S34. Preferably, the stable isotope of 3MBT is obtained by substituting one or more hydrogen atoms in 3MBT with an isotope of hydrogen element (D-form), more preferably two hydrogen atoms in 3MBT. Is substituted with isotope deuterium (D-form) (d2-3MBT). At this time, the substitution position of the hydrogen atom is not particularly limited, and any hydrogen atom on the structure of 3MBT can be substituted with an isotope.

  In the present invention, such a stable isotope of 3MBT can be prepared by substituting atoms on 3MBT by a conventional method. Alternatively, it can be prepared by substituting atoms in an intermediate in the process of synthesizing 3MBT. For example, d2-3MBT can be produced according to the following scheme.

  According to a third aspect of the present invention, there is provided a method according to the present invention which is carried out under both conditions (1) and (2). In other words, according to the third aspect of the present invention, there is provided a highly sensitive quantitative analysis method for 3MBT in a fermented malt beverage or beer-like beverage, wherein the analysis is performed by combining the purge and trap method and GC / MS, As a collection tube, a combination of two or more types of collection tubes containing poly (2,6-diphenyl-p-phenylene oxide) as a collection agent in each collection tube is used, and the inside A method using a stable isotope of 3-methyl-2-butene-1-thiol as a standard substance is provided. At this time, the combination of the two or more types of collection tubes collects the volatile components generated by heat desorption treatment of the first collection tube and the collection agent in the first collection tube. And at least one of the second collection tubes arranged so that at least one of the collection tubes has a collection efficiency for measurement noise components such as ethanol, carbon dioxide, and water. It has the structure which keeps low. According to a preferred embodiment, the first collection tube has a structure that suppresses the collection efficiency for measurement noise components such as ethanol, carbon dioxide, and water. Thus, by performing analysis using a specific collection agent and a specific internal standard substance, quantitative analysis of 3MBT can be performed with better accuracy up to a lower detection limit than in the past.

  FIG. 1 shows a schematic diagram of an example of an apparatus for carrying out purge and trap processing in the present invention. The purge and trap apparatus according to the present invention will be described below using the case of FIG. 1 as an example.

  First, a predetermined amount (for example, about 75 mL) of a specimen (fermented malt beverage or beer-like beverage) and a 3 MBT stable isotope, which is preferably an internal standard substance, are placed in the gas washing bowl 1 and in the bus 2 Soak in. The bath is filled with liquid (usually water since it does not need to be cold), the bath temperature is adjusted to 0 ° C. to 40 ° C., and the temperature of the subject in the bath is controlled to that temperature. An inert gas (for example, high-purity nitrogen gas) is blown into the subject, and 3MBT and 3MBT stable isotopes in the subject are purged (purged). At this time, the blowing time of the inert gas is usually about 5 to 10 minutes, and the blowing speed is usually 20 to 200 mL / min, preferably 50 to 100 mL / min. Moreover, although the temperature of blowing gas can be suitably set in consideration of bath temperature, it is -10-50 degreeC normally, Preferably it is 0-40 degreeC, More preferably, it is 10-20 degreeC. A trace volatile component containing 3 MBT that has been expelled is collected by the collection agent in the collection tube 3 in the purge and trap apparatus. At this time, at least poly (2,6-diphenyl-p-phenylene oxide) is used as a scavenger. The temperature of the collection tube at the time of collection, that is, the collection temperature is usually −5 to 50 ° C., preferably 10 to 40 ° C., more preferably 10 to 20 ° C. After the collection process, the collected components in the collection pipe are desorbed from the collection pipe by performing a heat desorption process. At this time, the heat desorption treatment can be performed by raising the temperature of the collection tube to about 180 ° C. or higher.

  Here, the expression of a value using “about” means to include a variation in a value that can be allowed by those skilled in the art to achieve the object by setting the value.

  Thus, according to one preferred embodiment of the present invention, in the method of the present invention, the blowing temperature of the inert gas is 0 to 40 ° C, the collection temperature in the collection tube is 10 to 40 ° C, and / or The desorption temperature in the collection tube is about 180 ° C.

Preferably, after the collection tube 3, as a second stage, a collection tube 4 filled with a collection agent is installed to collect in two stages. In this case, in the first-stage collection tube (collection tube 3 in this case), ethanol, carbon dioxide (CO ₂ ), water, or the like that interferes with analysis from volatile components expelled from the sample. As much as possible, remove as much as possible (measurement noise component) out of the system. Next, the collection tube 3 is subjected to a heat desorption process (for example, a temperature rising condition, a temperature rising from about 20 ° C. to about 180 ° C.), and a volatile component containing 3 MBT from which measurement noise components are removed as much as possible (preferably added to 3 MBT) The internal standard 3MBT stable isotope). Subsequently, 3MBT and preferably 3MBT stable isotopes are collected from the volatile component containing 3MBT in the second stage collection tube (collection tube 4 here). Even in the second-stage collection tube, trace noise components such as water, ethanol, and carbon dioxide gas that have migrated from the first stage can be broken through and discharged out of the system. Here, the component in the tube of the first-stage collection tube 3 is preferably a mixture of poly (2,6-diphenyl-p-phenylene oxide) as a collection agent and glass beads as a filler. It is. By adopting such a configuration, in the collection tube 3, a component containing 3MBT is collected in poly (2,6-diphenyl-p-phenylene oxide), and measurement noise components such as water and ethanol are included. While it is collected by the glass beads, the excess breaks through and is discharged out of the system. Moreover, the component in the tube of the second-stage collection tube 4 is preferably poly (2,6-diphenyl-p-phenylene oxide) (100% by weight) as a collection agent. Next, this collection tube 4 is subjected to a heat desorption process (for example, a temperature rise condition, the temperature is raised from about 20 ° C. to about 180 ° C.) to desorb volatile components including 3 MBT.

When the purge & trap process is completed, the volatile component containing 3MBT obtained from the collection tube is sent to the cryofocus trap 5 that has been cooled in advance with a conventional coolant such as liquid nitrogen, cooled, and concentrated. . Here, the temperature of the cooled cryofocus trap 5 is, for example, −200 ° C. to −50 ° C., preferably −70 ° C. to −180 ° C. Next, the temperature of the cryofocus trap is raised to, for example, 50 ° C. to 200 ° C., preferably 60 ° C. to 100 ° C., and a volatile component containing 3MBT cooled and concentrated in the cryofocus trap is injected into the capillary column.
As an apparatus for the purge & trap and the cryofocus trap, for example, a commercially available ENTECH INSTRUMENTS. Inc. 7100A (trade name) can be used.

In the cryofocus trap, gasified 3MBT and 3MBT stable isotopes are sent to a gas chromatograph by a carrier gas (for example, helium gas), and are injected into a capillary column there. As such a GC device, for example, a GC device manufactured by Agilent or Shimadzu Corporation can be used. As the capillary column used here, for example, a column having a length of 60 m, an inner diameter of 0.32 mm, and a film thickness of 1 μm can be used, and a commercially available product such as DB-1 (trade name) manufactured by Agilent is used. be able to. For example, the analysis temperature of the oven containing the capillary column should be set to 290 ° C. so that the temperature is increased by 10 ° C./min from 40 ° C. and increased to 20 ° C./min when it reaches 150 ° C. Can do.
3MBT in the sample separated by the capillary column is quantified by a mass spectrometer (MS). As such an MS device, for example, 5973 inert manufactured by Agilent can be used.

As described above, the 3MBT high-sensitivity quantitative analysis method according to the present invention quantitatively analyzes 3MBT with sufficient sensitivity and high accuracy in a concentration range lower than the sensory threshold concentration and lower than the conventional concentration range. It is something that can be done. Here, the “accuracy” of the analysis means the degree of “variation” of the analysis value when the analysis is repeatedly performed, and the high accuracy means a case where the variation is small. In the present invention, this accuracy is defined as follows. V. Can be evaluated by value.
C. V. Value (%) =
[Standard deviation of analysis value when repeatedly measured] / [Average value of analysis value] X 100
According to the present invention, C.I. V. The value is 5.0% or less, preferably 3.0% or less, and more preferably 2.0% or less. Therefore, the method according to the present invention has high accuracy and is advantageous in increasing the efficiency of analysis.

  Here, “high sensitivity” of the analysis means that the lower limit of the detection limit of 3 MBT is a smaller value. The detection limit value is defined as the concentration value of the analysis target substance when the detection limit is a concentration that gives S / N = 3. Here, S / N is represented by the ratio between the height of the signal peak of 3 MBT and the height of noise. According to the present invention, the detection limit value of 3 MBT, that is, the detectable concentration range of 3 MBT is preferably 0.11 ppt or more. Since the lower limit value of such a detection limit is a value of ½ or less compared to the conventional method, the present invention can be applied to the analysis of 3MBT, which is problematic even if contained in a trace amount in the beverage. This method can be said to have excellent analytical performance.

  Therefore, according to one preferred embodiment of the present invention, in the method according to the present invention, C.T. represents a variation in analysis value when the concentration range of 3MBT detectable is 0.11 ppt or more and is repeatedly measured. V. The value is 5.0% or less.

  The present invention will be described in detail by the following examples, but the present invention is not limited thereto.

Example 1: Examination of internal standard substance 75 mL of refrigerated commercial product beer (manufactured by Kirin Brewery Co., Ltd., “Ichiban Shibori” (trade name)) was put in a 250 mL gas washing bowl, and an antifoaming agent (silicon oil) was placed here. Was added in an amount of 0.01%, and methylethylmercaptan, 1-hexanethiol, or 3MBT stable isotope was added as an internal standard substance to 50 ppt each. Here, commercially available products were used for methyl ethyl mercaptan and 1-hexanethiol, and “d2-3MBT” synthesized according to the 3MBT stable isotope synthesis scheme described above was used as the 3MBT stable isotope.

  Each of the prepared samples was subjected to purge & trap and GC / MS under the conditions shown in Table 1 below. From the obtained results, 3 MBT C.I. V. Values and detection limits were obtained.

Here, C.I. V. As described above, the value (%) is an index representing the analysis accuracy, and represents the degree of “variation” of the result when repeatedly analyzing,
C. V. Value (%) =
[Standard deviation of analysis value when repeatedly measured] / [Average value of analysis value] X 100
Defined by
Therefore, C. for each sample. V. The value was calculated according to this definition.

  The detection limit value is defined as the concentration value of the analysis target substance when the detection limit is a concentration that gives S / N = 3. Here, S / N is represented by the ratio between the height of the signal peak of 3 MBT and the height of noise. Therefore, in this example, when the beer containing 3.1 ppt of 3MBT was analyzed, S / N was 88.0. From this value, the detection limit value was calculated to be 3.10 / (88.0 / 3) = 0.105. Therefore, it was found that the detection limit of 3 MBT here was 0.11 ppt.

The results are summarized as shown in Table 2.
From the results, it was found that the 3MBT stable isotope has the smallest variation and is the best as an internal standard. The obtained detection limit value was a value significantly lower than the sensory threshold value.

Example 2: Examination of collection agent 75 mL of refrigerated commercial product beer (Kirin Brewery Co., Ltd., “Ichiban Shibori” (trade name)) was placed in a 250 mL gas washing bowl, and the defoamer (silicone oil) was placed here. Was added in an amount of 0.01%, and an internal standard substance (d2-3MBT) was further added to 50 ppt. The obtained sample was subjected to purge & trap and GC / MS under the same conditions as in Example 1 except that the conditions of the collection agent were as described in (a) and (b) below. From the results obtained, it was found that 3 MBT C.I. V. Values and detection limits were obtained and evaluated.
Conditions for collection agent:
(a) The collector is only in one stage, and a composition comprising poly (2,6-diphenyl-p-phenylene oxide) (100% by weight) was used as the collector component (one-stage method). ).
(b) A two-stage collecting agent in the first and second stages under the same conditions as in Example 1 was used (two-stage method).

  The results were as shown in Table 3. It was possible to achieve superior detection accuracy and detection limit when the collection agent was in two stages rather than one stage.

Example 3: Preparation of a 3 MBT calibration curve 75 mL of a refrigerated commercial product beer (Kirin Brewery Co., Ltd., “Ichiban Shibori” (trade name)) is placed in a 250 mL gas washing jar so that the concentration is 0-30 ppt. A standard solution for a calibration curve was prepared by adding 3 MBT standard stock solution. Here, 0.01% of an antifoaming agent (silicone oil) was added thereto, and an internal standard substance (d2-3MBT) was further added so as to be 100 ppt. The obtained sample was subjected to purge & trap and GC / MS under the same conditions as in Example 1, and a calibration curve was created from the ratio of the obtained 3MBT and the peak area value of the internal standard substance.

The result was as shown in FIG.
The correlation coefficient in the calibration curve was r = 0.999, confirming that the method of the present invention was excellent in quantitative properties.

Example 4: Preparation of 3MBT calibration curve in wort 75mL of chilled wort was placed in a 250mL gas wash trough, and 3MBT standard stock solution was added to a concentration of 0-50ppt to prepare a standard solution for calibration curve. . An antifoaming agent (silicon oil) was added in an amount of 0.01%, and an internal standard substance (d2-3MBT) was added to 50 ppt. The obtained sample was subjected to purge & trap and GC / MS under the same conditions as in Example 1, and a calibration curve was created from the ratio of the obtained 3MBT and the peak area value of the internal standard substance.

  As a result, the correlation coefficient was r = 0.998, and it was confirmed that the method of the present invention was an excellent method for measuring 3MBT in semi-finished products during the manufacturing process.

Example 5: Effect of bath temperature 75 mL of refrigerated commercial product beer (manufactured by Kirin Brewery Co., Ltd., “Ichiban Shibori” (trade name)) is placed in a 250 mL gas washing bowl, and an antifoaming agent (silicon oil) is added here. An amount of 0.01% was added, and an internal standard substance (d2-3MBT) was further added to 100 ppt. The obtained sample was subjected to purge & trap and GC / MS under the same conditions as in Example 1 except that the bath temperature conditions were 5, 10, 20, and 40 ° C., respectively. The detection limit value was obtained from the obtained results and evaluated.

The results were as shown in Table 4.
Good detection sensitivity and accuracy could be achieved in the range of 5 to 40 ° C. without particularly cooling the bath temperature.

It is the schematic of the apparatus used for this invention. 6 is a graph showing a 3 MBT calibration curve obtained in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas washing tank 2 Bath 3 1st collection pipe 4 2nd collection pipe 5 Cryofocus trap 31 Glass bead 32 Poly (2, 6- diphenyl-p-phenylene oxide)
41 Poly (2,6-diphenyl-p-phenylene oxide)

Claims (9)

An inert gas is blown into the fermented malt beverage or beer-like beverage, and trace volatile components are expelled from the beverage and collected with a collection agent in a collection tube. High sensitivity of 3-methyl-2-butene-1-thiol, a sunlight odor component in fermented malt beverages or beer-like beverages, detected using a mass spectrometer after passing through a cryofocus trap and a capillary gas chromatography column A quantitative analysis method,
As the collecting tube, a single collecting component in which the component in the collecting tube is composed of poly (2,6-diphenyl-p-phenylene oxide) (50 to 100% by weight) and graphite carbon (50 to 0% by weight). Use a collecting tube, or use a combination of two or more collecting tubes comprising poly (2,6-diphenyl-p-phenylene oxide) as a collecting agent in at least each collecting tube. And (1) The combination of the two or more types of collection tubes is a volatile component generated by heat desorption treatment of the first collection tube and the collection agent in the first collection tube. And at least one second collection tube arranged to collect, wherein at least one of the collection tubes captures measurement noise components such as ethanol, carbon dioxide, and water. It has a structure that keeps the collection efficiency low. That,
(2) using a stable isotope of 3-methyl-2-butene-1-thiol as an internal standard substance,
The method is carried out under one or both of the conditions.   The first collecting tube has a structure capable of adjusting a contact amount of a trace volatile component passing through the collecting tube per unit amount of the collecting agent in the first collecting tube. The method described.   The weight percent of the collector poly (2,6-diphenyl-p-phenylene oxide) relative to all components in the first collector tube is less than the collector poly (2,2) relative to all components in the second collector tube. The method of Claim 1 or 2 set so that it may decrease compared with the weight% of 6-diphenyl-p-phenylene oxide).   The method according to any one of claims 1 to 3, wherein all the components in the second collection tube are made of poly (2,6-diphenyl-p-phenylene oxide).   A component in the first collection tube is poly (2,6-diphenyl-p-phenylene oxide) and a filler having substantially no collection ability for 3-methyl-2-butene-1-thiol; The method according to claim 1, comprising:   The method of claim 5, wherein the filler is glass beads. Inert gas blowing temperature is 0 to 40 ° C.,
The collection temperature in the collection tube is 10 to 40 ° C. and / or
The method according to any one of claims 1 to 6, wherein the desorption temperature in the collecting tube is about 180 ° C.   In the stable isotope of 3-methyl-2-butene-1-thiol, one or more of the hydrogen atoms in 3-methyl-2-butene-1-thiol are replaced with an isotope of hydrogen element (D-form) The method according to any one of claims 1 to 7, wherein   C. represents a variation in analytical value when the detectable concentration range of 3-methyl-2-butene-1-thiol is 0.11 ppt or more and measurement is repeated. V. The method according to any one of claims 1 to 8, wherein the value is 5.0% or less.

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