Metabonomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues (the metabolome) based on modern analytic technique with high throughput, high sensitivity, and high resolution. Gas chromatography-mass spectrometry (GC-MS) is used to gain qualitative results of detected metabolites for biological samples as it provides superior distinguishability, detection sensitivity and integrated standard mass spectrometry library. In this article, the historic developments of GC-MS and its application in metabonomics in the past several years were reviewed. Firstly, the classification and the derivative methods of GC-MS were introduced. Subsequently, sample pretreatment process, qualitative and quantitative analysis and data analysis during detecting metabolites by GC-MS were introduced, then its application in microorganism, plant and disease diagnosis was systematically summarized. Finally, the problems in metabonomics study based on GC-MS and the research prospect in the future were discussed.
Gas Chromatography-Mass Spectrometry ; methods ; Metabolomics ; methods

Objective: To establish a method for detection of 6 BTEXs in urine by Purge and Trap-Gas Chromatography-Mass Spectrometry. Methods: The urine sample need not be diluted, but directly purge and trap in the bottle, separated by gas chromatography column, then simultaneously analyzed by retention time locking (RTL) method and selective ion scanning mode (SIM) . Results: The linear range of 6 BTEXs in urine was good, the correlation coefficient was between 0.997 4 and 0.998 9. The minimum quantification limits was 0.010-0.036 μg/L. The precision was 1.9%-4.7%, and the recovery was 93.1%-101.9%. Conclusion: The method has the advantages of wide linear range, high sensitivity and recovery. It is suitable for the determination of 6 BTEXs in urine of low level occupational-exposed or non-exposed population.
Gas Chromatography-Mass Spectrometry/methods* ; Occupational Exposure

OBJECTIVES: To analyze the chemical structure of the interfering substance that affects the result of methamphetamine analysis in wastewater. METHODS: A combination of GC-MS and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was used to analyze the mass spectrum characteristics of the interfering substance that affects the result of methamphetamine analysis and to infer its possible structure. Liquid chromatography-triple quadrupole-mass spectrometry (LC-TQ-MS) was used to confirm the control material. RESULTS: Using LC-QTOF-MS in positive electrospray ionization (ESI⁺) mode, the mass-to-charge ratio (m/z) of quasi-molecular ion in the MS¹ mass spectrometry of interfering substance was identical to that of methamphetamine, indicating that the interfering substance was probably an isomer of methamphetamine. The MS² mass spectra obtained at three collision energies of 15 V, 30 V and 45 V were highly similar to methamphetamine, suggesting that the interfering substance contained methylamino and benzyl groups. Further analysis using GC-MS in electron impact (EI) ionization mode showed that the base peak in the mass spectrum of the interfering substance was at m/z 44. The interfering substance was confirmed to be N-methyl-2-phenylpropan-1-amine by compared with the standard reference. CONCLUSIONS The chemical structure of N-methyl-2-phenylpropan-1-amine is highly similar to methamphetamine, which is easy to cause interference for the detection of trace amounts of methamphetamine in wastewater using LC-TQ-MS. Therefore, in the actual analysis, the chromatographic retention time can be used to distinguish between N-methyl-2-phenylpropan-1-amine and methamphetamine.
Methamphetamine ; Wastewater ; Amines ; Gas Chromatography-Mass Spectrometry/methods* ; Mass Spectrometry/methods* ; Spectrometry, Mass, Electrospray Ionization/methods*

OBJECTIVES: To identify 1-(4-fluorophenyl)-2-(1-pyrrolidinyl) pentan-1-one (4-F-α-PVP) analog 1-(4-fluoro-3-methyl phenyl)-2-(1-pyrrolidinyl) pentan-1-one (4-F-3-Methyl-α-PVP) hydrochloride without reference substance. METHODS: The direct-injection electron ionization-mass spectrometry (EI-MS), GC-MS, electrospray ionization-high resolution mass spectrometry (ESI-HRMS), ultra-high performance liquid chromatography-high resolution tandem mass spectrometry (UPLC-HRMS/MS), nuclear magnetic resonance (NMR), ion chromatography and Fourier transform infrared spectroscopy (FTIR) were integrated utilized to achieve the structural analysis and characterization of the unknown compound in the sample, and the cleavage mechanism of the fragment ions was deduced by EI-MS and UPLC-HRMS/MS. RESULTS: By analyzing the direct-injection EI-MS, GC-MS, ESI-HRMS and UPLC-HRMS/MS of the compound in the samples, it was concluded that the unknown compound was a structural analog of 4-F-α-PVP, possibly with one more methyl group in the benzene ring. According to the analysis results of ¹H-NMR and ¹³C-NMR, it was further proved that the methyl group is located at the 3-position of the benzene ring. Since the actual number of hydrogen in ¹H-NMR analysis was one more than 4-F-3-Methyl-α-PVP neutral molecule, it was inferred that the compound existed in the form of salt. Ion chromatography analysis results showed that the compound contained chlorine anion (content 11.14%-11.16%), with the structural analysis of main functional group information by FTIR, the unknown compound was finally determined to be 4-F-3-Methyl-α-PVP hydrochloride. CONCLUSIONS A comprehensive method using EI-MS, GC-MS, ESI-HRMS, UPLC-HRMS/MS, NMR, ion chromatography and FTIR to identify 4-F-3-Methyl-α-PVP hydrochloride in samples is established, which will be helpful for the forensic science laboratory to identify this compound or other analog compounds.
Benzene ; Gas Chromatography-Mass Spectrometry/methods* ; Spectrometry, Mass, Electrospray Ionization ; Chromatography, High Pressure Liquid/methods*

OBJECTIVES: To establish a method to identify unknown sample based on the combined use of Fourier transform infrared spectroscopy (FTIR), gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-MS), ultra-high performance liquid chromatography-linear ion trap quadrupole-orbitrap mass spectrometry (UPLC-LTQ-Orbitrap MS) and ¹H-nuclear magnetic resonance spectroscopy (¹H-NMR) technique. METHODS: The unknown sample was directly analyzed by FTIR. The unknown sample was dissolved in methanol solution containing internal standard SKF_525A and the supernatant was detected by GC-QTOF-MS and UPLC-LTQ-Orbitrap MS. The unknown sample was dissolved in methanol-d4 solution for structural analysis of ¹H-NMR. RESULTS: The characteristic absorption peaks of FTIR spectra obtained from unknown sample were 1 682 (C=O bond), 1 503, 1 488, 1 436, 1 363, 1 256, 1 092, 1 035, 935, 840 and 800 cm^-1, the characteristic fragment ions (m/z) of GC-QTOF-MS were 86.096 4 (base peak), 58.065 1, 149.023 5, 121.028 6 and 65.038 6, the accurate mass [M+H]⁺ detected by UPLC-LTQ-Orbitrap MS was 236.127 7. The sample was identified as synthetic cathinone new psychoactive substance Eutylone by ¹H-NMR. CONCLUSIONS The method established in this study can be used for structural confirmation of Eutylone.
Methanol ; Chromatography, High Pressure Liquid/methods* ; Mass Spectrometry ; Gas Chromatography-Mass Spectrometry/methods* ; Magnetic Resonance Spectroscopy

OBJECTIVES: To establish an analytical method of the endosulfan concentrations （α-endosulfan and β-endosulfan） in biological samples by GC-MS/MS. To observe the distribution of endosulfan in aquatic animals and provide experimental evidence for forensic identification of relevant cases. METHODS: Acetonitrile was added to the blood and muscle samples for precipitating the protein. The endosulfan concentrations were determined by GC-MS/MS in multiple reaction monitoring mode. Qualitative analysis was performed according to the retention time and ion rate, and quantitative analysis was performed by external standard working curve method. RESULTS: In blood samples, the calibration curves of α-endosulfan and β-endosulfan ranging from 0.062 5 to 10 μg/mL had good linear relationship, the correlation coefficients （r） of which were >0.99. The limits of detection （LOD） were 1 ng/mL and 2 ng/mL and the limits of quantification （LOQ） were 4 ng/mL and 8 ng/mL, respectively. In muscle samples, the calibration curves of α-endosulfan and β-endosulfan ranging from 0.062 5 to 10 μg/g, the r of which were >0.98. The LOD were 1 ng/g and 4 ng/g and the LOQ were 4 ng/g and 16 ng/g, respectively. The accuracy of α-endosulfan and β-endosulfan was 90.76%-108.91% both in blood and muscle samples, the interday and intraday precision were 2.35%-8.71% and 5.44%-10.29%, respectively. In poisoning cases, endosulfan were detected in all parts of fish and crab and the content difference was statistically significant. CONCLUSIONS The endosulfan detection method based on GC-MS/MS established in the present study is rapid, sensitive and accurate, which can be applied to the endosulfan detection in traces biological samples. The distribution of endosulfan in fish and crab was different, which can provide evidence to the sample collection and analysis for toxicological analysis in relevant forensic identification.
Animals ; Chromatography, Gas/methods* ; Endosulfan/metabolism* ; Gas Chromatography-Mass Spectrometry/methods* ; Humans ; Limit of Detection ; Reproducibility of Results ; Tandem Mass Spectrometry/methods*

OBJECTIVETo establish a method for the simultaneous determination of 15 pesticides residues in Radix Paeoniae Alba by large volume injection-gas chromatography-mass spectrometry(LVI-GC-MS).

METHODSThe pesticides, including organochlorine pesticides, organophosphorus pesticides and pyrethroid insecticides, were analyzed by LVI-GC-MS using DB-5MS capillary column (30 m X 250 μm, 0.25 μm). The column temperature programming: initial temperature 40 degree for 1 min, with the increasing rate of 20 degree/min to 210 degree for 2 min, then with the increasing rate of 5 degree/min to 280 degree for 22 min. The flow of carrier gas was 1.0 ml/min with the injection volume of 15 μl.

RESULTSThe calibration curves of the pesticides were linear in the specified concentration ranges with correlation coefficients of 0.9937-0.9995. The average recoveries of the pesticides in Radix Paeoniae Alba spiked at two spiked levels ranged from 60.4 % to 106.8 % (for pendimethalin and 4, 4'-DDE those were 53.1 % and 45.2 %) with relative standard deviation(RSD) of 3.6 % to 18.6 % and the detection limits (S/N=3) were in the range of 0.16 μg/kg to 3.59 μg/kg.

CONCLUSIONThe established method for determination of multi-pesticide residue in Radix Paeoniae Alba is rapid, convenient and accurate with high sensitivity and low-cost.

OBJECTIVETo analyze the chemical compositions and their contents in non-alkaloids fraction from Radix Sophorae Tonkinensis.

METHODThe non-alkaloids from Radix Sophorae Tonkinensis were analyzed by gas chromatography/mass spectrometry after trimethylsilyl derivatization. The chemical compositions were identified by comparison of the authentic sample and NIST database; the contents of 19 identified components were determined by linear regression equation.

RESULT19 compounds constituting 34.72% of the non-alkaloids were identified. The major components were saccharides (5 compounds constituting 22.62%), organic acid (9 compounds constituting 11.81%), and others (5 compounds constituting 0.29%).

CONCLUSIONThe GC-MS is a simple, rapid and sensitive method to investigate the complex primary metabolites in plants.

OBJECTIVETo establish a method for determination of the epichlorohydrin in drinking water by isotope dilution gas chromatography-mass spectrometry (GC-MS).

METHODSThe internal standard solution D5-epichlorohydrin was added in drinking water sample. The epichlorohydrin was firstly collected by active carbon, and the adsorbent was then centrifuged at 2739 × g for 10 min to remove water. Finally, the epichlorohydrin was desorbed by dipping the active carbon in 1.0 ml acetone for 1 h. The desorbed solution was tested by GC-MS and quantified with isotopic internal standards. The detection limit, precision and accuracy of the assay were evaluated. This method was adopted to detect the epichlorohydrin in drinking water for 25 batches in a city.

RESULTSThe determination method of epichlorohydrin represented a good linear relationship in the range of 0.0645-3.8700 µg/L, the linear regression equation was Y = 2.828X + 4.91 × 10(-2) (r > 0.999). When the epichlorohydrin concentration were 0.0806, 0.3230 and 3.2300 µg/L, the relative standard deviations (RSD) were 7.9%, 4.7% and 3.1%, respectively. The average recoveries were from 95.7% to 98.7%. The limit of detection (LOD) was 0.015 µg/L, limit of quantification (LOQ) was 0.052 µg/L. The content of epichlorohydrin in the 25 cases of drinking water was under the limit of detection.

CONCLUSIONThe method is more simple than the national standard method, with high sensitivity, accuracy and good reproducibility, which is suitable for detection of the trace amounts of epichlorohydrin in drinking water.

Gas Chromatography-Mass Spectrometry ; methods ; Humans ; Malathion ; metabolism ; urine