Résumé
ObjectiveTo discriminate the age of Arisaema Cum Bile， the combination of headspace solid-phase microextraction （HS-SPME） with gas chromatography-mass spectrometry （GC-MS） was applied to explore the differences of volatile components of unfermented， 1-year fermented， 2-year fermented， and 3-year fermented Arisaema Cum Bile. MethodSamples with different fermentation durations were collected and HS-SPME-GC-MS technology was employed to detect the volatile components of each sample. The relative contents of detected volatile components were processed and analyzed by chemometrics methods such as principal component analysis （PCA）， hierarchical cluster analysis （HCA）， and partial least squares discriminant analysis （PLS-DA）. ResultThe results showed that 145 volatile components were identified. Among these volatile components， the relative contents of heterocyclic， alcohols， aldehydes and aromatics were high. PCA， HCA， and PLS-DA can effectively separate Arisaema Cum Bile with four different ages. Based on variable importance in projection （VIP） value > 1， 73 markers of differential volatile components were identified. The content of 2，6，11-trimethyldodecane and m-xylene in unfermented samples was the highest， and the content difference between them and those in fermented samples was significant （P<0.05）. 2，3-butanediol was detected only in 1-year samples， octane was detected only in 2-year samples， and ethyl heptanoate was detected only in 3-year samples. These components can be used as odor markers for Arisaema Cum Bile with different fermentation years. ConclusionThe identification method of volatile components of Arisaema Cum Bile was established by HS-SPME-GC-MS technology， which can realize the rapid identification of unfermented， 1-year fermented， 2-year fermented， and 3-year fermented samples， and provide a scientific basis for the standardization of processing technology and quality standards of Arisaema Cum Bile.
Résumé
ObjectiveTo screen the differential markers by analyzing volatile components in Dalbergia odorifera and its counterfeits， in order to provide reference for authentication of D. odorifera. MethodThe volatile components in D. odorifera and its counterfeits were detected by headspace gas chromatography-mass spectrometry（HS-GC-MS）， and the GC conditions were heated by procedure（the initial temperature of the column was 50 ℃， the retention time was 1 min， and then the temperature was raised to 300 ℃ at 10 ℃ for 10 min）， the carrier gas was helium， and the flow rate was 1.0 mL·min-1， the split ratio was 10∶1， and the injection volume was 1 mL. The MS conditions used electron bombardment ionization（EI） with the scanning range of m/z 35-550. The compound species were identified by database matching， the relative content of each component was calculated by the peak area normalization method， and principal component analysis（PCA）， orthogonal partial least squares-discrimination analysis（OPLS-DA） and cluster analysis were performed on the detection results by SIMCA 14.1 software， and the differential components of D. odorifera and its counterfeits were screened out according to the variable importance in the projection（VIP） value>2 and P<0.05. ResultA total of 26， 17， 8， 22， 24 and 7 volatile components were identified from D. odorifera， D. bariensis， D. latifolia， D. benthamii， D. pinnata and D. cochinchinensis， respectively. Among them， there were 11 unique volatile components of D. odorifera， 6 unique volatile components of D. bariensis， 3 unique volatile components of D. latifolia， 6 unique volatile components of D. benthamii， 8 unique volatile components of D. pinnata， 4 unique volatile components of D. cochinchinensis. The PCA results showed that， except for D. latifolia and D. cochinchinensis， which could not be clearly distinguished， D. odorifera and other counterfeits could be distributed in a certain area， respectively. The OPLS-DA results showed that D. odorifera and its five counterfeits were clustered into one group each， indicating significant differences in volatile components between D. odorifera and its counterfeits. Finally， a total of 31 differential markers of volatile components between D. odoriferae and its counterfeits were screened. ConclusionHS-GC-MS combined with SIMCA 14.1 software can systematically elucidate the volatile differential components between D. odorifera and its counterfeits， which is suitable for rapid identification of them.
Résumé
Objective To establish a rapid qualitative analysis method for volatile organic components in chemicals. Methods Headspace gas chromatography-mass spectrometry was used to qualitatively determine 19 volatile organic components, including benzene, 1,2-dichloroethane, and n-hexane, in chemicals. Different sample amounts, heating temperatures, heating times, and sample volumes were analyzed to assess their effects on detection results and optimize sampling conditions. Results Based on the set chromatography, the optimal sampling process of this method was as follows： 5.0 g sample in a 20.0 mL headspace bottle, incubated at 40 ℃ for 30 minutes in a constant-temperature drying incubator, and a 1.00 mL headspace gas injection. The within-run and between-run relative standard deviations of all components ranged from 0.00% to 21.05% and 0.00% to 33.33%, respectively. The samples stored in sealed glass containers were stable at room temperature for at least 60 days. Conclusion This method offers simplicity, good reproducibility, and stability, making it suitable for rapid qualitative analysis of volatile organic components in chemicals.
Résumé
ObjectiveBy comparing the differences in composition and content of volatile components between Atractylodis Macrocephalae Rhizoma（AMR）and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR， the effect of processing with rice-washed water on the volatile components in AMR and bran-fried AMR were investigated. MethodHeadspace gas chromatography-mass spectrometry（HS-GC-MS）was used to determine the volatile components in raw products， bran-fried products and their processed products with rice-washed water. GC conditions were programmed temperature（starting temperature of 50 ℃， rising to 140 ℃ at 10 ℃·min-1， maintained for 5 min， then rising to 210 ℃ at 4 ℃·min-1）， splitting ratio of 10∶1， high purity helium as the carrier gas and a solvent delay time of 3 min. MS conditions were an electron bombardment ion source（EI） with an electron collision energy of 70 eV， ion source temperature of 230 ℃， and the detection range of m/z 20-650. The relative contents of the components were determined by the peak area normalization method， the obtained sample data were subjected to principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） by SIMCA 14.1 software， and the differential components of AMR and bleaching AMR， and bran-fried AMR and bran-fried bleaching AMR were screened according to variable importance in the projection（VIP） value>1 and P<0.05. ResultA total of 71 volatile components were identified， including 53 in AMR， 50 in bleaching AMR， 51 in bran-fried AMR， and 44 in bran-fried bleaching AMR. OPLS-DA results showed that there were significant differences between AMR and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR， but not between AMR samples from different origins. The compound composition of AMR and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR did not change， but the contents of monoterpenes and sesquiterpenes changed significantly. ConclusionSignificant changes in the contents of volatile components were observed in AMR and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR， among them， 1，2-dimethyl-4-methylidenecyclopentene， 9，10-dehydro-isolongifolene， γ-elemene， zingiberene， atractylone， silphinene， modhephene and （1S，4S，4aS）-1-isopropyl-4，7-dimethyl-1，2，3，4，4a，5-hexahydronaphthalene can be used as candidate differential markers of volatile components of AMR before and after processing with rice-washed water.
Résumé
Objective @#To establish a headspace-gas chromatography ( HS-GC ) method for the determination of acetone and butanone, the biomarkers of occupational exposure to isopropanol and butanone, in urine of occupational populations. @*Methods @#Urine samples at 5.0 mL were transferred to a headspace bottle, added with 2.0 g anhydrous sodium sulfate, sealed immediately, and placed in a headspace sampler-gas chromatograph-mass spectrometer. Following heating at 60 ℃ for 30 min, 0.5 mL urine samples were injected and separated with the DB-FFAP capillary chromatographic column, and determined with the flame ionization detector. In addition, the retention time and peak area were determined. @*Results @#The peak area appeared a linear relationship with mass concentrations of acetone at 0.16-80 mg/L and butanone at 0.03-16 mg/L (correlation coefficient, 0.999 9), with detection limits of 0.009 and 0.004 mg/L, quantitation limits of 0.03 and 0.02 mg/L, respectively. The mean recovery rates of spiked samples were 93.67%-99.37% and 91.18%-94.41% for low, medium and high concentrations of acetone and butanone, and the relative standard deviations of 1.53%-3.69% and 2.54%-6.58%, respectively. @*Conclusion @#A highly sensitive and repeatable HS-GC method is successfully established for simultaneous determination of acetone and butanone in urine samples by optimizing sample pretreatment and separation, which is feasible for qualitative and quantitative analyses of acetone and butanone in urine.
Résumé
ObjectiveTo establish a method for the determination of 8 volatile halogenated hydrocarbons in drinking water， including vinyl chloride， trichloroethylene， tetrachloroethylene， tetrachloromethane， chloroform， dichlorobromomethane， dichlorodibromomethane， and tribromomethane by headspace thermal desorption-gas mass spectrometry. MethodsThe water sample was kept in the headspace bottle at 60 ℃ for 40 min， and the volatile matter was transferred to the cold trap，subjected to thermal desorption， then analyzed by gas chromatography-mass spectrometry. ResultsThe linear ranges were 0.2‒20.0 μg·L-1 for vinyl chloride， 0.1‒20.0 μg·L-1 for chloroform， 0.02‒20.00 μg·L-1 for tetrachloromethane， 0.2‒20.0 μg·L-1 for trichloroethylene， 0.3‒20.0 μg·L-1 for dichlorobromomethane， 0.1‒20.0 μg·L-1 for tetrachloroethylene， 0.4‒20.0 μg·L-1 for dichlorodibromomethane， and 1.0‒20.0 μg·L-1 for tribromomethane. All the correlation coefficients were more than 0.997. The respective quantitative limits were 0.162， 0.073， 0.016， 0.184， 0.270， 0.071， 0.356 and 0.813 μg·L-1， and the respective recoveries were 98.0%‒101.0%， 102.0%‒110.0%， 99.2%‒101.0%， 95.5%‒96.2%， 96.0%‒102.0%， 100.0%‒102.0%， 99.0%‒105.0%， and 94.0%‒103.0%. ConclusionThe method is simple， sensitive， rapid， accurate and reliable， so it is applicable for the determination of 8 kinds of volatile halogenated hydrocarbons in drinking water.
Résumé
ObjectiveBy comparing the difference of volatile components of the decoction pieces before and after being processed by braising method of Jianchangbang and steaming method included in the 2020 edition of Chinese Pharmacopoeia， the influence of processing methods on the flavor formation of Polygoni Multiflori Radix （PMR） was compared. MethodHeadspace-gas chromatography-mass spectrometry （HS-GC-MS） was used to detect the volatile components of 30 batches of PMR samples from 3 origins with 3 processing methods. The GC was performed under programmed temperature （starting temperature of 40 ℃， rising to 150 ℃ at 5 ℃·min-1， and then rising to 195 ℃ at 10 ℃·min-1） with high purity helium as carrier gas and the split ratio of 10∶1. Mass spectrometry conditions were electron impact ion source （EI） and the detection range of m/z 50-650， the peak area normalization method was used to calculate the relative mass fraction of each component. The chromaticity values of different processed products were measured by a precision colorimeter， the relationship between chromaticity values and relative contents of volatile components was investigated by OriginPro 2021， principal component analysis （PCA） and orthogonal partial least squares-discriminant analysis （OPLS-DA） were performed on the sample data by SIMCA14.1. The differential components of different processed products of PMR were screened according to the principle of variable importance in the projection （VIP） value>1.5， and the material basis of different odor formation of PMR and its processed products was explored. ResultA total of 59 volatile components were identified， among which 34 were raw products， 33 were braised products， and 27 were steamed products. PCA and OPLS-DA results showed that there were significant differences between the three， but there was no significant difference between samples from different origins of the same processing method. Color parameters of a*， b*， E*ab had no significant correlation with contents of volatile components， while L* was negatively correlated with contents of 2-methyl-2-butenal， 2-methyltetrahydrofuran-3-one and 2，3-dihydro-3，5-dihydroxy-6-methyl-4（H）-pyran-4-one （P<0.05）. The contents of pungent odor components such as caproic acid， nonanoic acid and synthetic camphor decreased after processing， while the contents of sweet flavor components such as 2-methyl-2-butenal， furfural and 5-hydroxymethylfurfural increased after processing， and the contents of furfural， 5-methyl-2-furanmethanol， 5-hydroxymethylfurfural and other aroma components in the braised products were significantly higher than that in the steamed products. ConclusionHS-GC-MS can quickly identify the volatile substance basis that causes the different odors of PMR and its processed products. The effect of processing methods on the odor is greater than that of origin. There is a significant correlation between the color parameter of L* and contents of volatile components， the "raw" taste of PMR may be related to volatile components such as caproic acid， pelargonic acid and synthetic camphor， the "flavor" after processing may be related to the increase of the contents of 2-methyl-2-butenal， furfural， 5-hydroxymethylfurfural， methyl maltol and furfuryl alcohol.
Résumé
ObjectiveOn the basis of sensory evaluation， the changes of volatile components in gecko before and after processing were compared， and the odor correction effect of different processing methods of gecko was discussed. MethodRaw products， fried yellow products， vinegar processed products， wine processed products， talcum powder scalding products and white wine sprayed products after scalding talcum powder of gecko were prepared， and 10 odor assessors were invited to evaluate the 6 samples in turn by sensory evaluation. Headspace solid-phase microextraction-gas chromatography-mass spectrometry （HS-SPME-GC-MS） and relative odor activity value （ROAV） were used to analyze the key odor components， and multivariate statistical methods were used to analyze the difference of volatile components between raw and processed products of gecko. Taking water-soluble extract and protein contents as internal indicators， sensory evaluation score and content ranking of differential components as external indicators， and assigning a weight of 0.25 to them respectively， the comprehensive scores of raw products and processed products of gecko were calculated to evaluate the odor correction effect of each processing method. ResultThe average sensory evaluation scores of the raw products， fried yellow products， vinegar processed products， wine processed products， talcum powder scalding products and white wine sprayed products after scalding talcum powder of gecko were 1.6， 5.2， 6.2， 6.1， 7.2 and 8.0， respectively. ROAV results showed that key components affecting odor of gecko were 2-ethyl-3，5-dimethylpyrazine， isovaleraldehyde， trimethylamine， 1-octen-3-ol， n-octanal， nonanal， 2-methylnaphthalene， γ-octanolide， 2-heptanone and phenol. Principal component analysis （PCA） significantly distinguished raw products from processed products. Orthogonal partial least squares-discriminant analysis （OPLS-DA） results showed that there were 16， 13， 16， 16， 16 differential components between raw products， fried yellow products， vinegar processed products， wine processed products， talcum powder scalding products and white wine sprayed products after scalding talcum powder of gecko. Among these differential components， there were 4 common components， namely， the contents of different odor components （2-methylnaphthalene and 2-ethyl-p-xylene） decreased， while the contents of different flavor components （2-decanone and 2，3，5-trimethylpyrazine） increased. The comprehensive scoring results showed that the odor correction effect of each processed products was in the order of talcum powder scalding products>wine processed products>vinegar processed products>fried yellow products>white wine sprayed products after scalding talcum powder. ConclusionTalcum powder scalding is a better method to improve the odor of gecko， and it can provide an experimental basis for the processing of gecko to correct the odor.
Résumé
ObjectiveTo analyze the quality changes of Platycladi Semen before and after the deterioration of moth-eaten and rancidity during storage. MethodFour types samples of Platycladi Semen， including normal， moth-eaten， oxidative rancidity and hydrolytic rancidity， were determined for volatile components， odor， and taste based on headspace solid phase microextraction/gas chromatography-mass spectrometry （HS-SPME/GC-MS） and electronic sensory techniques such as electronic nose and electronic tongue. Volatile components were identified by searching the database and manual comparison， the odor and taste were determined by the response values of the electronic nose and electronic tongue sensors， and the difference between samples before and after deterioration was studied by multivariate statistical analysis. ResultA total of 85 compounds were identified in Platycladi Semen samples. Compared with the normal samples， the number of volatile compounds in samples after hydrolytic rancidity decreased by 5， the number of volatile compounds in samples after moth-eaten and oxidative rancidity increased by 1 and 21， respectively. Aldehydes and acids accounted for majority of types. Among them， the contents of N-hexanoic acid， hexanal and propionic acid in the samples of oxidative rancidity reached 11.49%， 10.21% and 7.52%， which became the key indicators of rancidity. There was significant variance among the odor components corresponding to W1W， W2W and W1S sensors by electronic nose analysis. It was indicated that the value of sourness in deteriorated samples generally increased by mean of electronic tongue analysis. Compared with normal samples， the moth-eaten samples had changed slightly and rancidity samples had changed significantly especially oxidative rancidity samples of volatile components， odor and taste by multivariate statistical analysis. ConclusionIn terms of Platycladi Semen， the oxidative rancidity caused by nature storage for 12 months has the greatest impact on the quality. Therefore， it should be mainly to prevent oxidative rancidity to ensure the quality of Platycladi Semen.
Résumé
Objective@#To develop a headspace gas chromatography ( HS-GC ) assay for simultaneous determination of dichloroacetic acid ( DCA ) and trichloroacetic acid ( TCA ) in urine.@*Methods@#Urine samples (5 mL) were transferred to a 22 mL headspace bottle, added with 0.5 mL 10% sodium acetate solution , immediately sealed, and shaken evenly. The bottle was placed in the HS-GC system, and equilibrated at 90 ℃ for 60 minutes. The mixture was separated with the HP-INNOWAX chromatographic column, and the DCA and TCA concentrations were detected with the hydrogen flame detector.@*Results@#Under the optimal experimental conditions, the correlation coefficient of DCA and TAC was both > 0.999 0 within the range of 10-500.0 μg/L, and the lowest detection limits of DCA and TAC were 2.0 and 3.5 μg/L, with the spike recovery rate of 87.40% to 101.44%, and relative standard deviations of 1.89% to 3.25%. Of the 35 urine samples sampled from occupational populations, DCA and TCA were not detected.@*Conclusions@#The establishment of the HS-GAS assay through addition of sodium acetate and optimization of the headspace conditions, has high recovery and precision, which is effective to meet the requirements for daily determination of DCA and TCA in urine samples.
Résumé
Objective: To establish a method for the determination of methyl isobutyl ketone (MIBK) in urine samples by headspace-gas chromatography-mass spectrometry. Methods: Automatic headspace sampling technique was adopted to optimize the headspace conditions (headspace bottle heating temperature and equilibration time) and gas chromatographic conditions. A total of 5 ml samples were taken and added with 3.0 g ammonium sulfate into a 20 ml headspace bottle. After heated at 60 ℃ for 30 mins, gas from the upper part of headspace bottle was injected into gas chromatography with an injection volume of 100 μl. The target was separated by HP-5MS UI (30 m×0.25 mm×0.25 μm) capillary column and then detected by mass spectrometry detector. The retention time and external standard method were used for qualitative and quantitative analysis of MIBK in samples, respectively. Results: The standard curve of MIBK showed significant linearity between 20.0-1 000.0 μg/L. The standard curve was y=62.9x-652.5, and the correlation coefficient r=0.9998. The detection limit of MIBK was 5.0 μg/L and the quantification limit of MIBK was 16.0 μg/L. The average recovery rate was 95.3%~100.2% at three spiked concentrations of low (50.0 μg/L) , medium (200.0 μg/L) and high (500.0 μg/L) . The intra-day and inter-day precisions were 1.7%~3.8% (n=6) and 1.2%~4.0% (n=6) respectively. This method was stable for the determination of MIBK, and the urine could be kept 14 d at -20 ℃ without significantly loss. Conclusion: This method is proved to be simple, practical and highly sensitive. It can satisfy the request for the determination of urine samples of workers exposed to MIBK.
Sujets)
Humains , Chromatographie gazeuse-spectrométrie de masse , Butyl méthyl cétoneRésumé
ObjectiveBy comparing the composition and content changes of the volatile components in Atractylodis Rhizoma before and after processing with rice-washed water， the effect of rice-washed water processing on volatile components in Atractylodis Rhizoma was investigated. MethodHeadspace-gas chromatography-mass spectrometry （HS-GC-MS） was used to detect the volatile components in rhizomes of Atractylodes chinensis and A. lancea， and their processed products of rice-washed water. Chromatographic conditions were programmed temperature （starting temperature of 50 ℃ for 2 min， rising to 120 ℃ with the speed of 10 ℃·min-1， then rising to 170 ℃ at 2.5 ℃·min-1， and rising to 240 ℃ at 10 ℃·min-1 for 3 min）， the inlet temperature was 280 ℃， the split ratio was 10∶1， and the solvent delay time was 3 min. The conditions of mass spectrometry were electron bombardment ionization （EI） with ionization temperature at 230 ℃ and detection range of m/z 20-650. Then the relative content of each component was determined by the peak area normalization method. SIMCA 14.1 software was used to perform unsupervised principal component analysis （PCA） and supervised orthogonal partial least squares-discriminant analysis （OPLS-DA） on each sample data， the differential components of Atractylodis Rhizoma and its processed products were screened by the principle of variable importance in the projection （VIP） value>1. ResultA total of 60 components were identified， among which 40 were rhizomes of A. chinensis and 38 were its processed products， 46 were rhizomes of A. lancea and 47 were its processed products. PCA and OPLS-DA showed that the 4 kinds of Atractylodis Rhizoma samples were clustered into one category respectively， indicating that the volatile components of the two kinds of Atractylodis Rhizoma were significantly changed after processing with rice-washed water， and there were also significant differences in the volatile components of rhizomes of A. lancea and A. chinensis. The compound composition of Atractylodis Rhizoma and its processed products was basically the same， but the content of the compounds was significantly different. The differential components were mainly concentrated in monoterpenoids and sesquiterpenoids， and the content of monoterpenoids mostly showed a decreasing trend. ConclusionAfter processing with rice-washed water， the contents of volatile components in rhizomes of A. lancea and A. chinensis are significantly changed， and pinene， 3-carene， p-cymene， ocimene， terpinolene， atractylon， acetic acid and furfural can be used as difference markers before and after processing.
Résumé
ObjectiveBy comparing the composition and content changes of the volatile components in Atractylodis Rhizoma before and after processing with rice-washed water， the effect of rice-washed water processing on volatile components in Atractylodis Rhizoma was investigated. MethodHeadspace-gas chromatography-mass spectrometry （HS-GC-MS） was used to detect the volatile components in rhizomes of Atractylodes chinensis and A. lancea， and their processed products of rice-washed water. Chromatographic conditions were programmed temperature （starting temperature of 50 ℃ for 2 min， rising to 120 ℃ with the speed of 10 ℃·min-1， then rising to 170 ℃ at 2.5 ℃·min-1， and rising to 240 ℃ at 10 ℃·min-1 for 3 min）， the inlet temperature was 280 ℃， the split ratio was 10∶1， and the solvent delay time was 3 min. The conditions of mass spectrometry were electron bombardment ionization （EI） with ionization temperature at 230 ℃ and detection range of m/z 20-650. Then the relative content of each component was determined by the peak area normalization method. SIMCA 14.1 software was used to perform unsupervised principal component analysis （PCA） and supervised orthogonal partial least squares-discriminant analysis （OPLS-DA） on each sample data， the differential components of Atractylodis Rhizoma and its processed products were screened by the principle of variable importance in the projection （VIP） value>1. ResultA total of 60 components were identified， among which 40 were rhizomes of A. chinensis and 38 were its processed products， 46 were rhizomes of A. lancea and 47 were its processed products. PCA and OPLS-DA showed that the 4 kinds of Atractylodis Rhizoma samples were clustered into one category respectively， indicating that the volatile components of the two kinds of Atractylodis Rhizoma were significantly changed after processing with rice-washed water， and there were also significant differences in the volatile components of rhizomes of A. lancea and A. chinensis. The compound composition of Atractylodis Rhizoma and its processed products was basically the same， but the content of the compounds was significantly different. The differential components were mainly concentrated in monoterpenoids and sesquiterpenoids， and the content of monoterpenoids mostly showed a decreasing trend. ConclusionAfter processing with rice-washed water， the contents of volatile components in rhizomes of A. lancea and A. chinensis are significantly changed， and pinene， 3-carene， p-cymene， ocimene， terpinolene， atractylon， acetic acid and furfural can be used as difference markers before and after processing.
Résumé
The volatile oil of Chuanxiong Rhizoma(CX) is known as an effective fraction. In order to seek a suitable method for processing CX and its decoction pieces, this study selected 16 volatile components as indices to investigate how different processing methods such as washing/without washing, sun-drying, baking, oven-drying and far-infrared drying at different temperatures affected the quality of CX and its decoction pieces(fresh CX was partially dried, cut into pieces, and then dried) by headspace gas chromatography-mass spectrometry(GC-MS), cluster analysis, principal component analysis and comprehensive weighted scoring. The results showed that the rapid washing before processing did not deteriorate the volatile components of CX. Considering the practical condition of production area, oven-drying was believed to be more suitable than sun-drying, baking, and far-infrared drying. The CX decoction pieces with a thickness of 0.3-0.4 cm were recommended to be oven-dried at 50 ℃. The integrated processing(partial drying, cutting into pieces, and drying) did not cause a significant loss of volatile components. For the fresh CX, the oven-drying at 60 ℃ is preferred. The temperature should not exceed 60 ℃, and drying below 60 ℃ will prolong the processing time, which will produce an unfavorable effect on volatile components. This study has provided the scientific evidence for field processing of CX, which is conducive to realizing the normalization and standardization of CX processing in the production area and stabilizing the quality of CX and its decoction pieces.
Sujets)
Dessiccation , Chromatographie gazeuse-spectrométrie de masse/méthodes , Huile essentielle , Analyse en composantes principales , Rhizome/composition chimique , Composés organiques volatils/analyseRésumé
ABSTRACT: Climatic conditions in the mid-northern region of Mato Grosso State in Brazil are favorable for beekeeping. However, since 2011, the honey production chain has suffered losses because the production of off-odor honey has made it impossible to market the honey. Reports from beekeepers indicated a relationship between the off-odor in the honey and the nectar of Borreria verticillata (L.) G. Mey (Rubiaceae). In this study, the botanical origins and volatile profiles of ten off-odor honeys (H1-H10) and flowers of B. verticillata were evaluated. Palynological and sensorial analyses of the honeys were performed; a scale from 1 to 4 was applied for the sensorial analysis, in which 1 indicates no off-odor and 4 indicates extreme off-odor. Analysis of volatile was performed by using headspace solid-phase microextraction and gas chromatography-mass spectroscopy methods. The honeys investigated were classified with very high to intense off-odors, except H4 and H5, which did not differ from the control honey (no off-odor). Palynological analyses showed that honeys H1-H4, H7, and H9 were monofloral from B. verticillata, whereas in H5, H6, H8, and H10 this pollen were accessory. However, there was no quantitative correlation between the B. verticillata pollen content and the off-odor attributes of the honeys. Skatole was identified in all of the honeys except H4, H5, and the control honeys, suggesting that skatole contributed to the off-odor attributes of the products. However, further studies are required to investigate the origin of the skatole because it is not transferred directly from B. verticillata flowers to the honey.
RESUMO: As condições climáticas da região Centro-Norte do Estado de Mato Grosso são favoráveis a apicultura, contudo ocorrem prejuízos nesta cadeia produtiva desde 2011 devido a produção de mel com odor indesejável, o que impossibilitou sua comercialização. Relatos dos apicultores apontaram relação da ocorrência do odor indesejável no mel com o néctar Borreria verticillata (L.) G. Mey (Rubiaceae). Neste estudo foi avaliado a origem botânica e o perfil de voláteis de méis (M1 até M10) com odor indesejável e das flores de B. verticillata. Foi realizada a análise polínica do mel e também sensorial, empregando-se uma escala de um a quatro pontos, em que um refere-se a nenhum odor desagradável e quatro, extremo odor desagradável. A análise de compostos voláteis no mel e nas flores de B. verticillata foi realizada utilizando microextração em fase sólida por headspace e cromatografia gasosa acoplada a detector por espectrometria de massas. Os méis investigados foram classificados desde muito a extremo odor desagradável, exceto os méis M4 e M5, que não diferiram do mel controle (sem odor indesejável). Os méis M1 até M4, M7 e M9 eram monoflorais de B. verticillata, enquanto M5, M6, M8 e M10 o pólen B. verticillata era acessório. Todavia, não foi observada correlação quantitativa entre o teor deste pólen e o atributo odor indesejável. O escatol foi identificado nos méis investigados, exceto em M4, M5 e mel controle. Estes resultados sugerem que o escatol contribuiu para o atributo odor desagradável do produto. Contudo, mais estudos devem ser conduzidos para investigar a origem do odor indesejável, porque o escatol não foi transferido diretamente das flores para o mel.
Résumé
Headspace-solid phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) were used to analyze the interaction between the β-lactoglobulin (β-LG) and the botany volatile organic compounds (BVOCs) from pomelo peel to screen out the pharmacodynamic active BVOCs substance group. The selective binding effect between β-LG and BVOCs was analyzed by quantitative recovery of BVOCs, and the binding parameters were calculated. Then, the molecular model of BVOCs binding with β-LG was established by molecular docking and spectroscopic method, and the molecular mechanism of interaction between pharmacodynamic active BVOCs and β-LG was discussed from the perspective of omics. The results showed that dipentene (Dt), linalylacetate (La) and nootkatone (Nt) of BVOCs were selected by HS-SPME/GC-MS by the interaction of β-LG and BVOCs substance group. Parameter calculation showed that β-LG had the strongest affinity with Nt, but the binding force was not strong, and the affinity for La was the weakest. The affinity of β-LG to Dt was weak, but the binding force was the strongest, with a binding rate of 54. 66%, indicating that the selective binding strength of β-LG with the pharmacodynamic active BVOCs depended on the chemical structure of BVOCs molecules. The β-LG preferred to bind to the aldehyde and ketone BVOCs molecules containing carbonyl oxygen structure. The molecular model of β-LG and BVOCs group (Dt, La, Nt) was established to evaluate the binding position of BVOCs group (Dt, La, Nt) on β-LG. The loosening, extension and conformational change of β-LG secondary structure caused by the introduction of BVOCs are the result of van der Waals force, hydro-phobicity and hydrogen bonding. This study provides a new method for screening pharmacodynamic active BVOCs from the perspective of whole substance group of BVOCs, and provides a useful reference for investigating the binding mechanism between pharmacodynamic active BVOCs and functional protein molecules from the perspective of omics.
Résumé
Objective:To establish and apply a new practical analytical method for identifying the fishy odor of Cordyceps based on headspace-solid phase microextraction-gas chromatography-triple quadrupole mass spectrometry （HS-SPME/GC-QQQ-MS/MS） technique. Method:The InertCap Pure-WAX capillary column （0.25 mm×30 m， 0.25 μm） was used for chromatographic separation. The injection port temperature was set at 250 ℃. The injection mode was split injection with a ratio of 5∶1. High purity helium was used as the carrier gas and control mode was set to constant pressure. The column flow rate was 1.43 mL∙min<sup>-1</sup>， the linear velocity was 43.3 cm∙s<sup>-1</sup>， and the purge flow rate was 3.0 mL∙min<sup>-1</sup>. The chromatographic column temperature program as follows：maintained the initial temperature at 50 ℃ for 5 min， and increased the temperature at a rate of 10 ℃∙min<sup>-1</sup> to 250 ℃， held for 10 min. The column equilibrium time was 2.0 min. The ion source of mass spectrographic analysis was electron ionization with ion source temperature of 200 ℃， and the monitoring mode was set to multiple reaction monitoring. Result:Seven batches of Cordyceps samples were collected， including 3 batches from Sichuan， 3 batches from Qinghai and 1 batch from Tibet. There were six batches of counterfeits， including 3 batches from Sichuan， 2 batches from Guizhou and 1 batch in Xinjiang. A total of 81 volatile compounds were screened out in Cordyceps， which could be divided into 13 types （esters， ketones， aldehydes and others） according to the compound structure， indicating that the fishy odor of Cordyceps was a complex odor. There was no significant difference in the types of volatile compounds of Cordyceps from different regions， which suggested that these volatile compounds in Cordyceps produced in Tibet （Naqu）， Qinghai （Yushu and Guoluo） and Sichuan （Litang， Rangtang and Seda） were relatively consistent. However， the contents of some volatile compounds in Cordyceps produced in different regions were quite different， and 16 volatile compounds with significant difference were screened out， including 1-methoxy-2-propyl acetate， <italic>γ</italic>-octalactone， hexyl acetate and others， those compounds maybe could been used as the quality markers for identification of regions of Cordyceps. There was a large difference in volatile compounds between Cordyceps and its counterfeits， and 34 volatile compounds were screened out， including ethyl acetate， acetophenone， 2-ethyl-1-hexanol and others， those compounds maybe could been used as the quality markers for authenticity identification of Cordyceps. Conclusion:In summary， the established method for identifying the fishy odor of Cordyceps in this paper has the characteristics of high sensitivity， accuracy and simplicity， which can provide reference for the analysis of volatile compounds in other Chinese herbal medicines.
Résumé
OBJECTIVE: To establish a method for the determination of formic acid in urine by automatic headspace-gas chromatography-mass spectrometry. METHODS: The urine sample was added with 3 mL 15.00%(V/V) sulfuric acid ethanol and heated in an automatic headspace sampler. The formic acid and ethanol underwent an esterification reaction to produce ethyl formate which was separated by gas chromatographic column and detected by mass spectrometer. The quantification was based on external standard method. RESULTS: The linear range of the method was 2.93-97.60 mg/L, with the regression equation correlation coefficient of 0.999 5. The detection limit was 0.65 mg/L and the minimum quantitative limit was 2.17 mg/L, with the recoveries of 95.61%-106.47%. The within-run relative standard deviation(RSD) ranged from 2.52% to 8.05% and the between-run RSD ranged from 6.58% to 8.42%. CONCLUSION: The method has simple pretreatment, good specificity, high precision and has little interference. It is suitable for large scale rapid determination of formic acid in urine in occupational contact population, patients with acute methanol poisoning and general population.
Résumé
This study adopted headspace-gas chromatography-mass spectrometry(HS-GC-MS) and electronic nose to detect volatile components from Myristicae Semen samples with varying degrees of mildew, aiming at rapidly identifying odor changes and substance basis of Myristicae Semen mildew. The experimental data were analyzed by electronic nose and principal component analysis(PCA). The results showed that Myristicae Semen samples were divided into the following three categories by electronic nose and PCA: mildew-free samples, slightly mildewy samples, and mildewy samples. Myristicae Semen samples with different degrees of mildew greatly varied in volatile components. The volatile components in the samples were qualitatively and quantitatively detected by HS-GC-MS, and 59 compounds were obtained. There were significant differences in the composition and content in Myristicae Semen samples with different degrees of mildew. The PCA results were the same as those by electronic nose. Among them, 3-crene, D-limonene, and other terpenes were important indicators for the identification of mildew. Bicyclo[3.1.0]hexane, 4-methylene-1-(1-methylethyl)-, terpinen-4-ol, and other alcohols were key substances to distinguish the degree of mildew. In the later stage of mildew, Myristicae Semen produced a small amount of hydroxyl and aldehyde compounds such as acetaldehyde, 2-methyl-propionaldehyde, 2-methyl-butyraldehyde, and formic acid, which were deduced as the material basis of the mildew. The results are expected to provide a basis for the rapid identification of Myristicae Semen with different degrees of mildew, odor changes, and the substance basis of mildew.
Sujets)
Nez électronique , Chromatographie gazeuse-spectrométrie de masse , Odorisants/analyse , Sperme/composition chimique , Microextraction en phase solide , Composés organiques volatils/analyseRésumé
Objective: To analyze and compare the volatile components of Jiuwei Qianghuo pills, granules and oral liquid. Methods: The volatile components of Jiuwei Qianghuo pills, granules and oral liquid were analyzed and compared by the head-space solid-phase microextraction and gas chromatography-mass spectrometry(HS-SPME-GC-MS), the relative percentage of each component was calculated using the area normalization method, and the principal component analysis was also performed. Results: A total of 90 kinds of volatile components were identified from Jiuwei Qianghuo pills, accounting for 97.19% of the total volatile components; 27 kinds of volatile components were identified from Jiuwei Qianghuo granules, accounting for 92.92% of the total volatile components;22 kinds of volatile components were identified from Jiuwei Qianghuo oral liquid, accounting for 87.60% of the total volatile components. A total of 111 volatile components were identified in the three preparations, of which 6 were common components, but the contents of the common components were different. The specific components of the pills, granules and oral liquid were 68, 8 and 13, respectively. Moreover, the comprehensive scores of the three dosage forms in the principal component analysis showed a large difference, with the high, middle and low values for the pills, granules and oral liquid, respectively. Conclusion: The composition and content of volatile components were different in the Jiuwei Qianghuo pill, granule and oral liquid preparations. From the point of view of the volatility, the comprehensive score of Jiuwei Qianghuo pills is higher than that of granules and oral liquid.