CN112666292A - Pretreatment method for determining tetramethylpyrazine in solid matrix and application thereof - Google Patents
Pretreatment method for determining tetramethylpyrazine in solid matrix and application thereof Download PDFInfo
- Publication number
- CN112666292A CN112666292A CN202011473230.1A CN202011473230A CN112666292A CN 112666292 A CN112666292 A CN 112666292A CN 202011473230 A CN202011473230 A CN 202011473230A CN 112666292 A CN112666292 A CN 112666292A
- Authority
- CN
- China
- Prior art keywords
- tetramethylpyrazine
- leaching
- pretreatment method
- solid matrix
- solid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention relates to the technical field of analysis and detection, and discloses a pretreatment method for determining tetramethylpyrazine in a solid matrix, which comprises the following steps: s1, leaching the solid matrix by using an acidic buffer solution, and performing solid-liquid separation to obtain a leaching solution; s2, adding NaCl into the leaching liquor to obtain a saturated solution; s3, adjusting the saturated solution to be alkaline, and performing extraction treatment to obtain a sample to be detected; the pretreatment method disclosed by the invention is used for treating the solid matrix by adopting a method of leaching and extracting with an acidic buffer solution, and limits the pH value of the acidic buffer solution, the leaching temperature and time, the pH value of the saturated solution, the selection of the extracting agent and the extraction time in the pretreatment process, so that a sample to be detected which can directly enter a gas chromatograph for quantitative analysis can be obtained.
Description
Technical Field
The invention relates to the technical field of analysis and detection, in particular to a pretreatment method for determining tetramethylpyrazine in a solid matrix and application thereof.
Background
The tetramethylpyrazine in the white spirit is produced by Maillard reaction in the processes of starter propagation and stacking fermentation, and is carried into the white spirit by distillation. The tetramethylpyrazine has the effects of expanding blood vessels, improving microcirculation and inhibiting platelet accumulation, thereby endowing the white spirit with healthy efficacy. At present, the detection technology for tetramethylpyrazine in white spirit is mature, and the detection is usually carried out by directly adopting a gas chromatography or a liquid chromatography under the condition of not needing to carry out pretreatment on a sample, so that the result is accurate and reliable.
The solid matrix is solid raw materials involved in the fermentation process of the white spirit, and comprises Daqu, distiller's grains and the like. In the prior art, the tetramethylpyrazine in the solid matrix is mostly determined by adopting a gas chromatography, and the method has the advantages of little environmental pollution caused by basically no waste liquid, simpler and more convenient operation and easier maintenance compared with a liquid chromatography and the like. However, since the solid matrix has a complex structure and components and cannot be directly injected, a sample needs to be pretreated when tetramethylpyrazine therein is measured. At present, in the prior art, a headspace solid phase microextraction method (HS-SPME) is mostly adopted for pretreating samples, although the method is convenient to operate, the material cost is high, and the extraction effect is gradually attenuated along with the increase of extraction times, so that the samples are difficult to process in batches, and the method is not suitable for being popularized in small and medium-sized enterprises.
Therefore, a pretreatment method suitable for batch processing of samples, which has high accuracy, convenient operation and low cost, is urgently needed for the determination of tetramethylpyrazine in solid matrix.
Disclosure of Invention
One of the objectives of the present invention is to overcome the deficiencies of the prior art, and to provide a pretreatment method for measuring tetramethylpyrazine in a solid substrate, so as to at least achieve the effects of being suitable for batch processing of samples, high accuracy, convenient operation, and low cost.
The purpose of the invention is realized by the following technical scheme: a pretreatment method for measuring tetramethylpyrazine in a solid matrix comprises the following steps:
s1, leaching the solid matrix by using an acidic buffer solution, and performing solid-liquid separation to obtain a leaching solution;
s2, adding NaCl into the leaching liquor to obtain a saturated solution;
and S3, adjusting the saturated solution to be alkaline, and extracting to obtain a sample to be detected.
In certain embodiments, the solid substrate comprises at least one of distillers grains and daqu.
In some embodiments, in S1, the mass-to-volume ratio of the solid matrix to the acidic buffer is 1:3 to 5.
In certain embodiments, S1, the solid substrate has a mass of 5 to 10 g.
In certain embodiments, the pH of the acidic buffer in S1 is 3.5 to 5.5.
In certain embodiments, the acidic buffer in S1 is selected from at least one of a citric acid-sodium citrate buffer, a disodium hydrogen phosphate-citric acid buffer, and an acetic acid-sodium acetate buffer.
In the embodiment, since too low pH can prolong the operation time and can cause the ingredient distribution in the fermented grains or the yeast to change, thereby influencing the extraction, the pH of the acidic buffer solution is limited, so that not only can the operation time be better controlled and the ingredient change be prevented, but also the solubility of the tetramethylpyrazine can be improved, and the leaching effect can be better improved.
In certain embodiments, in S1, the leaching is performed at room temperature for 20-30 min; and/or the method of solid-liquid separation comprises one of centrifugation and filtration.
In certain embodiments, in S3, the pH of the saturated solution is adjusted to 8.0 to 10.0 with NaOH.
In the embodiment, the pH value of the saturated solution is adjusted to 8.0-10.0, so that the solubility of the tetramethylpyrazine in a water phase can be reduced, and the extraction effect is better improved.
In certain embodiments, in S3, the extraction is liquid-liquid extraction; preferably, the liquid-liquid extraction extractant comprises ethyl acetate; more preferably, the time of the liquid-liquid extraction is 10-20 min.
In this embodiment, the extraction effect can be further improved by limiting the extraction agent and the extraction time.
The second purpose of the invention is to provide the application of the pretreatment method in the determination of tetramethylpyrazine in solid matrix.
In certain embodiments, the method of determining is gas chromatography.
It is worth noting that the solid matrix is treated by adopting a method of leaching and extracting with an acidic buffer solution, the pH value of the acidic buffer solution, the leaching temperature and time, the pH value of the saturated solution, the selection of the extracting agent and the extraction time in the pretreatment process are limited, the solubility of the tetramethylpyrazine is improved, so that a sample to be tested which can directly enter a gas chromatograph for quantitative analysis is obtained, and the effects of high sample recovery rate and accurate test result are achieved.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the pretreatment method for measuring tetramethylpyrazine in the solid matrix, tetramethylpyrazine in the solid matrix is extracted by the method of leaching and extracting with the acidic buffer solution, so that the solubility of tetramethylpyrazine can be improved, and a sample to be measured which can be directly subjected to gas chromatography for quantitative analysis can be obtained.
2. The pretreatment method for measuring tetramethylpyrazine in solid matrix is convenient for popularization and promotion in small and medium-sized enterprises.
Drawings
FIG. 1 is a graph comparing leaching effects at different pH;
FIG. 2 is a graph comparing the extraction effect at different pH values;
FIG. 3 is a graph comparing the extraction results of different extractants;
FIG. 4 is a graph comparing the extraction results at different extraction times.
Detailed Description
The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.
Example 1
A pretreatment method for measuring tetramethylpyrazine in a solid matrix comprises the following steps:
s1, weighing 5g of solid matrix (Daqu or vinasse) in a 50mL centrifuge tube or beaker;
s2, soaking a solid substrate in a disodium hydrogen phosphate-citric acid buffer solution with the pH value of 3.5, wherein the mass-to-volume ratio of the solid substrate to the disodium hydrogen phosphate-citric acid buffer solution is 1:3, leaching for 20min at room temperature, placing the obtained suspension in a centrifuge, centrifuging at the speed of 5000r/min, and taking clear liquid to obtain a leaching solution;
s2, adjusting the leaching liquor to saturation by using NaCl to obtain a saturated solution;
and S3, adjusting the pH value of the saturated solution to 8.0 by adopting NaOH, and carrying out liquid-liquid extraction on the saturated solution for 10min under the condition that ethyl acetate is used as an extracting agent to obtain a sample to be detected.
Example 2
A pretreatment method for measuring tetramethylpyrazine in a solid matrix comprises the following steps:
s1, weighing 10g of solid matrix (Daqu or vinasse) in a 50mL centrifuge tube or beaker;
s2, soaking the solid substrate in a citric acid-sodium citrate buffer solution with the pH value of 5.5, wherein the mass-volume ratio of the solid substrate to the citric acid-sodium citrate buffer solution is 1:5, leaching for 30min at room temperature, and filtering the obtained suspension with absorbent cotton to obtain a leaching solution;
s2, adjusting the leaching liquor to saturation by using NaCl to obtain a saturated solution;
and S3, adjusting the pH value of the saturated solution to 10.0 by adopting NaOH, and carrying out liquid-liquid extraction on the saturated solution for 20min under the condition that ethyl acetate is used as an extracting agent to obtain a sample to be detected.
Example 3
A pretreatment method for measuring tetramethylpyrazine in a solid matrix comprises the following steps:
s1, weighing 7g of solid matrix (Daqu or vinasse) in a 50mL centrifuge tube or beaker;
s2, soaking the solid matrix in an acetic acid-sodium acetate buffer solution with the pH value of 4, wherein the mass-volume ratio of the solid matrix to the acetic acid-sodium acetate buffer solution is 1:4, leaching for 25min at room temperature, and filtering the obtained suspension with absorbent cotton to obtain a leaching solution;
s2, adjusting the leaching liquor to saturation by using NaCl to obtain a saturated solution;
and S3, adjusting the pH value of the saturated solution to 9.0 by adopting NaOH, and carrying out liquid-liquid extraction on the saturated solution for 15min under the condition that ethyl acetate is used as an extracting agent to obtain a sample to be detected.
Example 4
S1, weighing 9g of solid matrix (Daqu or vinasse) in a 50mL centrifuge tube or beaker;
s2, soaking a solid matrix in an acetic acid-sodium acetate buffer solution with the pH value of 4.0, wherein the mass-volume ratio of the solid matrix to the acetic acid-sodium acetate buffer solution is 1:3.5, leaching for 27min at room temperature, placing the obtained suspension in a centrifuge, centrifuging at the speed of 5000r/min, and taking clear liquid to obtain a leaching solution;
s2, adjusting the leaching liquor to saturation by using NaCl to obtain a saturated solution;
and S3, adjusting the pH value of the saturated solution to 8.5 by adopting NaOH, and carrying out liquid-liquid extraction on the saturated solution for 14min under the condition that ethyl acetate is used as an extracting agent to obtain a sample to be detected.
Example 5
S1, weighing 8g of solid matrix (Daqu or vinasse) in a 50mL centrifuge tube or beaker;
s2, soaking a solid substrate in a disodium hydrogen phosphate-citric acid buffer solution with the pH value of 5.0, wherein the mass-to-volume ratio of the solid substrate to the disodium hydrogen phosphate-citric acid buffer solution is 1:4.5, leaching for 24min at room temperature, placing the obtained suspension in a centrifuge, centrifuging at the speed of 5000r/min, and taking clear liquid to obtain a leaching solution;
s2, adjusting the leaching liquor to saturation by using NaCl to obtain a saturated solution;
and S3, adjusting the pH value of the saturated solution to 9.5 by adopting NaOH, and carrying out liquid-liquid extraction on the saturated solution for 18min under the condition that ethyl acetate is used as an extracting agent to obtain a sample to be detected.
Example 6
S1, weighing 6g of solid matrix (Daqu or vinasse) in a 50mL centrifuge tube or beaker;
s2, soaking a solid substrate in a citric acid-sodium citrate buffer solution with the pH value of 4.5, wherein the mass-volume ratio of the solid substrate to the citric acid-sodium citrate buffer solution is 1:4, leaching for 22min at room temperature, placing the obtained suspension in a centrifuge, centrifuging at the speed of 5000r/min, and taking clear liquid to obtain a leaching solution;
s2, adjusting the leaching liquor to saturation by using NaCl to obtain a saturated solution;
and S3, adjusting the pH value of the saturated solution to 8.5 by adopting NaOH, and carrying out liquid-liquid extraction on the saturated solution for 16min under the condition that ethyl acetate is used as an extracting agent to obtain a sample to be detected.
Effect verification
1. To verify the effect of the pH of the acidic leach liquor of the present invention on the leaching performance, comparative experiments were conducted. The test method comprises the following steps: respectively setting the pH values of the acidic leaching solution to be 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5 and 7.0, and measuring the leaching effect of each group; wherein, the leaching effect is evaluated by the peak area of tetramethylpyrazine measured by gas chromatography.
As can be seen from fig. 1, when the pH is less than 3.5, the peak area of tetramethylpyrazine increases but is not obvious as the pH of the acidic leaching solution decreases; when the pH value is more than 5.5, the peak area of the tetramethylpyrazine is gradually reduced along with the increase of the pH value of the acidic leaching liquor, namely the solubility of the tetramethylpyrazine in the water phase is gradually reduced. Therefore, when the pH value of the acid leaching solution is 3.5-5.5, the leaching effect of the tetramethylpyrazine is good.
2. To verify the effect of pH extraction on the extraction effect in the present invention, comparative experiments were performed. The test method comprises the following steps: respectively setting the pH value of the acidic leaching solution to 7.5, 8.0, 8.5, 9.0, 9.5 and 10.0, and measuring the extraction effect of each group; wherein, the extraction effect is evaluated by the peak area of tetramethylpyrazine measured by gas chromatography.
As can be seen from fig. 2, when the pH is 7.5, the peak area of tetramethylpyrazine is significantly increased, that is, the solubility of tetramethylpyrazine in the aqueous phase is significantly increased, and the extraction effect is poor. Therefore, when the pH value of the extraction is 8.0-8.5, the extraction effect of the tetramethylpyrazine is good.
3. To verify the effect of the extractant of the present invention on extraction, comparative experiments were performed. The test method comprises the following steps: respectively taking ethyl acetate, dichloromethane and cyclohexane as extracting agents, and determining the extraction effect of each group; wherein, the extraction effect is evaluated by the peak area of tetramethylpyrazine measured by gas chromatography.
As can be seen from fig. 3, the peak area is the largest when ethyl acetate is used as the extractant, i.e., the effect of ethyl acetate on tetramethylpyrazine extraction is the best.
4. To verify the effect of the extraction time on the extraction effect in the present invention, comparative experiments were performed. The test method comprises the following steps: comparing the extraction effect of the extraction time within 5-60 min; wherein, the extraction effect is evaluated by the peak area of tetramethylpyrazine measured by gas chromatography.
As can be seen from FIG. 4, the peak area is the largest when the extraction time is 10-20 min, i.e., the extraction effect is the best when the extraction time is 10-20 min.
5. In order to verify the influence of the pretreatment method of the present invention on the measurement accuracy of the gas chromatography, a test was performed. The test method comprises the following steps: pretreating the Daqu and the fermented grains respectively by the methods of the embodiments 1 to 6, and performing gas chromatography analysis on the obtained sample to be detected. The results are shown in the following table:
as can be seen from the above table, the pretreatment method of the present invention can achieve very high measurement precision when used to treat a solid substrate. Specifically, the precision of Daqu is 2.71%, and the precision of fermented grains is 9.59%.
6. In order to verify the influence of the pretreatment method of the present invention on the sample recovery rate of gas chromatography, a test was performed. The test method comprises the following steps: dividing the high-temperature Daqu and the piled fermented grains of the Maotai-flavor liquor into 6 groups respectively, adding the standard substances, pretreating the groups by the methods of examples 1 to 6 respectively, and carrying out gas chromatography analysis on the obtained samples to be tested. The results are shown in the following table:
as can be seen from the above table, the pretreatment method of the present invention can achieve a very high sample recovery rate when applied to a solid substrate. Specifically, the standard recovery rate of the Daqu is 83.23-91.34%, and the standard recovery rate of the fermented grains is 87.15-117.22%. It should be understood that the recovery rate of the test reaches more than 100% after the pre-treatment of the fermented grains by the method of the embodiment 4 to 5, and the phenomenon belongs to a normal phenomenon, which is clearly specified in pharmacopoeia of the people's republic of china 2015 edition: the recovery rate ranges from 80% to 120%. The causes of the above-mentioned phenomena are many, such as systematic errors and sample matrix effects.
In conclusion, the pretreatment method for measuring tetramethylpyrazine in solid matrix provided by the invention is suitable for batch processing of samples, and has the effects of high accuracy, high recovery rate, convenience in operation and low cost.
The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A pretreatment method for measuring tetramethylpyrazine in a solid matrix is characterized by comprising the following steps:
s1, leaching the solid matrix by using an acidic buffer solution, and performing solid-liquid separation to obtain a leaching solution;
s2, adding NaCl into the leaching liquor to obtain a saturated solution;
and S3, adjusting the saturated solution to be alkaline, and extracting to obtain a sample to be detected.
2. The pretreatment method for assaying tetramethylpyrazine according to claim 1, wherein the solid substrate comprises at least one of distiller's grains and Daqu.
3. The pretreatment method for determining tetramethylpyrazine in solid matrix according to claim 1, wherein in S1, the mass-to-volume ratio of the solid matrix to the acidic buffer is 1: 3-5.
4. The pretreatment method for detecting tetramethylpyrazine in solid substrates according to claim 1, wherein in S1, pH of the acidic buffer is 3.5-5.5.
5. The pretreatment method for assaying tetramethylpyrazine according to claim 4, wherein in S1, the acidic buffer is at least one selected from the group consisting of citric acid-sodium citrate buffer, disodium hydrogen phosphate-citric acid buffer and acetic acid-sodium acetate buffer.
6. The pretreatment method for detecting tetramethylpyrazine in solid matrix according to claim 1, wherein in S1, the leaching is performed at room temperature for 20-30 min; and/or the method of solid-liquid separation comprises one of centrifugation and filtration.
7. The pretreatment method for detecting tetramethylpyrazine in solid substrates according to claim 1, wherein in S3, NaOH is used to adjust the pH of the saturated solution to 8.0-10.0.
8. The pretreatment method for detecting tetramethylpyrazine in solid matrix according to claim 1, wherein in S3, the extraction is liquid-liquid extraction; preferably, the liquid-liquid extraction extractant comprises ethyl acetate; more preferably, the time of the liquid-liquid extraction is 10-20 min.
9. Use of the pretreatment method according to any one of claims 1 to 8 for the determination of tetramethylpyrazine in solid substrates.
10. Use according to claim 9, wherein the method of determination is gas chromatography.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011473230.1A CN112666292A (en) | 2020-12-15 | 2020-12-15 | Pretreatment method for determining tetramethylpyrazine in solid matrix and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011473230.1A CN112666292A (en) | 2020-12-15 | 2020-12-15 | Pretreatment method for determining tetramethylpyrazine in solid matrix and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112666292A true CN112666292A (en) | 2021-04-16 |
Family
ID=75404426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011473230.1A Pending CN112666292A (en) | 2020-12-15 | 2020-12-15 | Pretreatment method for determining tetramethylpyrazine in solid matrix and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112666292A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102928536A (en) * | 2012-11-01 | 2013-02-13 | 泸州品创科技有限公司 | Method for extracting and analyzing aroma substances in yeast for making hard liquor |
| CN103852543A (en) * | 2014-03-12 | 2014-06-11 | 贵州茅台酒股份有限公司 | Method for rapidly, simply and conveniently extracting volatile flavor substances from fermented grains |
| CN104341359A (en) * | 2014-11-11 | 2015-02-11 | 武汉武药制药有限公司 | Preparation method of tetramethyl-pyrazine |
| CN111707740A (en) * | 2020-05-19 | 2020-09-25 | 贵州茅台酒股份有限公司 | Method for measuring flavor substances in yeast for making hard liquor |
-
2020
- 2020-12-15 CN CN202011473230.1A patent/CN112666292A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102928536A (en) * | 2012-11-01 | 2013-02-13 | 泸州品创科技有限公司 | Method for extracting and analyzing aroma substances in yeast for making hard liquor |
| CN103852543A (en) * | 2014-03-12 | 2014-06-11 | 贵州茅台酒股份有限公司 | Method for rapidly, simply and conveniently extracting volatile flavor substances from fermented grains |
| CN104341359A (en) * | 2014-11-11 | 2015-02-11 | 武汉武药制药有限公司 | Preparation method of tetramethyl-pyrazine |
| CN111707740A (en) * | 2020-05-19 | 2020-09-25 | 贵州茅台酒股份有限公司 | Method for measuring flavor substances in yeast for making hard liquor |
Non-Patent Citations (3)
| Title |
|---|
| LEOBARDO SERRANO-CARREON等: "A SIMPLE PROTOCOL FOR EXTRACTION AND DETECTION OF PYRAZINES PRODUCED BY FUNGI IN SOLIO STATE FERMENTATION", 《BIOTECHNOLOGY TECHNIQUES》 * |
| 孙啸涛等: "涡旋辅助液液微萃取结合GC-MS法检测67种白酒中四甲基吡嗪、4-甲基愈创木酚和4-乙基愈创木酚", 《食品科学》 * |
| 王柏文等: "应用液-液萃取结合GC-MS与GC-NPD技术对国井芝麻香型白酒中含氮化合物的分析", 《食品科学》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110389185A (en) | The solid phase extraction method of a variety of steroid hormones and the detection method to the steroid hormone in a kind of saliva | |
| CN112748198A (en) | Method and device for detecting antifungal drugs in serum by liquid chromatography tandem mass spectrometry technology | |
| CN105067734A (en) | Method for determining content of natamycin in wine | |
| CN112666292A (en) | Pretreatment method for determining tetramethylpyrazine in solid matrix and application thereof | |
| CN109541062B (en) | Method for simultaneously measuring concentration of personal care products in surface water or sewage | |
| CN112608270A (en) | Isotope compound and preparation method and application thereof | |
| CN114755354A (en) | Kit for detecting folic acid and method for detecting folic acid in whole blood sample | |
| CN110007023B (en) | High-resolution mass spectrum screening method for sulfonamides in fish body and analysis method for interaction of sulfonamides and protein macromolecules | |
| CN114778737B (en) | Liquid chromatography detection sample pretreatment method capable of shortening time | |
| CN114216983A (en) | Method for detecting residual quantity of medocard in animal food by liquid chromatography-tandem mass spectrometry | |
| CN108387656B (en) | Method for detecting bis (hydroxymethyl) imidazolidinyl urea in cosmetics through liquid chromatography-mass spectrometry | |
| CN111337611A (en) | Method for detecting malachite green, leucomalachite green, crystal violet and leucocyte crystal violet in aquatic products | |
| CN111665315B (en) | Detection and analysis method of anticancer drugs in natural water body | |
| CN114778737A (en) | Liquid chromatography detection sample pretreatment method capable of shortening time | |
| CN109490439A (en) | The detection method of pivalic acid in ampicillin and/or ampicillin sodium | |
| CN115639289A (en) | Pretreatment method for determination of tetrahydrocannabinic acid in domestic sewage | |
| CN114324557B (en) | Zeta-globin detection method based on MALDI-TOF MS | |
| CN114965780A (en) | Method for simultaneously measuring 30 psychoactive substances in environmental water body | |
| CN111443147B (en) | Method for detecting salbutamol in food | |
| CN114720570B (en) | Method for detecting 8 estrogens in fish meat | |
| CN102253036B (en) | Filtration interception method for detecting trace amounts of proteins in traditional Chinese medicine injection | |
| CN117030882A (en) | Method for detecting content of thiopyrimidine in aquatic product | |
| CN116448916A (en) | Detection method of indole total alkaloids in toad extract | |
| CN116465979A (en) | Quantitative analysis method of fenugreek lactone in yellow wine | |
| CN116593623A (en) | High-sensitivity liquid chromatography-tandem mass spectrometry analysis method for determining concentration of human plasma phloroglucinol |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |