The study was carried in Chemistry Department of University of Sciences and Entomology Department of National Institute of Malariology - Parasitology - Entomology during the period of 2001-2002. A manual syringe for SPME was made by using a fused silica fiber from optical cable, one of the end of the fiber is passed through the hole of a needle of 5mL medical syringe and is attached to a piston in a protective holder of 1mL medical syringe, and the other end is coated by liquid phase polyacrylate (the fiber end in a 0.1g/mL solution of polyacrylate in dichloromethane). Then the liquid sample to adsort analytes during 30-45 minutes. At the end, the 2 needle is inserted into the GC/ECD injector port is desorbed the analytes on to the column
Syringes ; Solid Phase Microextraction ; Pyrethrins

OBJECTIVETo establish a method for determination of 2,5-hexanedione in urine by headspace solid-phase microextraction-gas chromatography.

METHODSAfter extraction by solid-phase microextraction head, 2,5-hexanedione in urine was determined by gas chromatography and was quantified by external standard method.

RESULTSThe concentration of 2,5-hexanedione in urine showed a linear relationship within the range of 0.1-20.0 µg/ml. The regression equation was y=261.36x-1.903 3, r=0.999 2. The minimum detectable concentration was 0.01 µg/ml. The recovery rate was 92.6%-97.1%, with a relative standard deviation (RSD) of 3.3%-5.8%. The intra-day and inter-day RSDs were 3.8%-6.2% and 4.7%-6.3% respectively.

CONCLUSIONThis determination method has no requirement for organic solvents, features simple and rapid operation, possesses higher detection sensitivity, and applies well to the determination of 2,5-hexanedione in urine.

Chromatography, Gas ; Hexanones ; urine ; Humans ; Sensitivity and Specificity ; Solid Phase Microextraction

Currently, the main sample pretreatment methods for forensic toxic analysis are liquid-liquid extraction （LLE） and solid-phase extraction （SPE）. As a simple, convenient, and low-cost LLE method, dispersion liquid-liquid microextraction （DLLME） has high enrichment factor and good extraction efficiency, and therefore has attracted the attention of many researchers in the field of toxicology analysis in recent years. As a multi-functional microextraction method, DLLME has been widely used in the analysis of pesticides, sleeping sedatives, drugs and heavy metal poisons in forensic toxic analysis. Meanwhile, it can also be used in combination with such a variety of analytical instruments as gas chromatography-electron capture detectors （GC-ECD）, high performance liquid chromatography-diode array detectors （HPLC-DAD）. As a sample pretreatment method, DLLME has the advantages of simple operation, less use of organic solvent, reliable results and good reproducibility, thus can meet the requirements of modern court toxic analysis.
Forensic Toxicology ; Liquid Phase Microextraction ; Reproducibility of Results ; Solid Phase Extraction ; Solvents

OBJECTIVETo predict the stable life for Mentha haplocalyx.

METHODThe volatiles in M. haplocalyx were analyzed by head-space solid micro-extraction, coupled with GC-MS and a comprehensive evaluation of essential oil in M. haplocalyx was analyzed using the factor analysis. The prediction was carried out by initial average rate stability tests using the content of essential oil and the main volatiles as indices.

RESULTPrincipal component analysis indicated that pulegone and isomenthone can fully describe the quality of prepared slices. The t(0.9, 20 degrees C) was 5.49 years and 2.88 years respectively, carried out by essential oil, pulegone and isomenthone.

CONCLUSIONThe stable life for M. haplocalyx under 20 degrees C was 2.88 years.

Drug Stability ; Gas Chromatography-Mass Spectrometry ; Mentha ; chemistry ; Monoterpenes ; analysis ; Oils, Volatile ; analysis ; Solid Phase Microextraction

OBJECTIVETo analyze and compare the volatile constituents from M. biondii and M. liliflora.

METHODThe volatile constituents were extracted by head-space solid-phase microextraction, and analyzed by GC-MS.

RESULTSeventy two constituents were identified from M. biondii and M. liliflora, the content of the 25 constituents in both samples were similar, while the kinds of the constituents were obviously different.

CONCLUSIONThe volatile constituents were different between M. biondii and M. liliflora.

Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Gas Chromatography-Mass Spectrometry ; Magnolia ; chemistry ; Solid Phase Microextraction ; Volatilization

OBJECTIVEHeadspace solid-phase microextraction (HS-SPME) was used pre-concentration procedure for the determination of tetrahydrofuran in urine by gas chromatography with hydrogen flame detector.

METHODSSeveral parameters controlling SPME was studied and optimised: SPME fiber, extraction time and extraction temperature, desorption time and desorption temperature.

RESULTSUnder optimal conditions, the correlation coefficient was 0.9998 and good recoveries (range from 93.0% ∼ 100.8%) were achieved, the detection limit was 0.5 µg/L.

CONCLUSIONThe method can be applied to the determination of trace amount of tetrahydrofuran in urine.

Chromatography, Gas ; methods ; Furans ; urine ; Humans ; Occupational Exposure ; analysis ; Solid Phase Microextraction ; methods

The aim of this study is to validate an integrated air monitoring approach for assessing airborne formaldehyde (FA) in the workplace. An active sampling by silica gel impregnated with 2,4-dinitrophenylhydrazine, a passive solid phase microextraction technique using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine as on-fiber derivatization reagent, an electrochemical direct-reading monitor, and an enzyme-based badge were evaluated and tested over a range of 0.020–5.12 ppm, using dynamically generated FA air concentrations. Simple linear regression analysis showed the four methods were suitable for evaluating airborne FA. Personal and area samplings in 12 anatomy pathology departments showed that the international occupational exposure limits in the GESTIS database were frequently exceeded. This monitoring approach would allow a fast, easy-to-use, and economical evaluation of both current work practices and eventual changes made to reduce FA vapor concentrations.
Chromatography ; Formaldehyde* ; Humans ; Linear Models ; Occupational Exposure ; Pathology ; Silica Gel ; Solid Phase Microextraction

OBJECTIVETo compare and analyze volatile constituents from flowers of Trichosanthes kirilowii, in order to point out characteristic differences between female and male flowers.

METHODBlooming female and male flowers were collected in the same place. Volatile constituents were extracted from the flower by solid phase micro-extraction (SPME), then separated and analyzed by gas chromatography-mass-spectrometry (GC-MS).

RESULTFifty-two and forty-five chromatographic peaks were separated from the female and male flowers, respectively. Forty seven constituents were identified and their relative percentage compositions were determined with the peak area normalization method. Linalool, alpha-farnesene, benzene methanol, and (Z)-2-methylbutanal oxime were the main volatile constituents. The contents of linalool and alpha-farnesene in female flower were remarkably higher than those in male. In contrast, the content of benzene methanol in male flower was remarkably higher than that in female.

CONCLUSIONIn the first study on chemical constituents from flowers in genus Trichosanthes, 37 compounds are separated from T. kirilowii. Contents of linalool, alpha-farnesene and benzene methanol show the characteristic differences of volatile constituents contained in male and female flowers of T. kirilowii, which enriches the basic studies on dioecious plant.

Flowers ; chemistry ; Gas Chromatography-Mass Spectrometry ; Solid Phase Microextraction ; Trichosanthes ; chemistry ; Volatile Organic Compounds ; analysis ; chemistry ; isolation & purification

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.
Electronic Nose ; Gas Chromatography-Mass Spectrometry ; Odorants/analysis* ; Semen/chemistry* ; Solid Phase Microextraction ; Volatile Organic Compounds/analysis*

OBJECTIVES: To explore the relationship between the change rules of volatile organic compounds （VOCs） in rat muscle and postmortem interval （PMI）. METHODS: A total of 120 healthy rats were divided randomly into 12 groups （10 for each group）. After the rats were sacrificed by cervical dislocation, the bodies were kept at （25±1） ℃. Rat muscle samples were separately obtained at 12 PMI points, including 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 d. The VOCs in rat muscles were collected, detected and analyzed by headspace solid-phase microextraction （HS-SPME） coupled to gas chromatography-mass spectrometer （GC-MS）. RESULTS: In total, 15 species of VOCs were identified, including 9 aromatic compounds, 3 sulfur compounds, 2 aliphatic acids and 1 heterocyclic compound. The species of VOCs increased with PMI： no species were detected within 1 day, 3 species were detected on day 2, 9 on day 3, 11 on day 4, 14 from day 5 to 7, and 15 from day 8 to 10. Total peak area of 15 species of VOCs was significantly correlated to PMI （adjusted R²=0.15-0.96）： the regression function was y=-17.05 x²+ 164.36 x-246.36 （adjusted R²=0.96） from day 2 to 5, and y=2.24 x+101.13 （adjusted R²=0.97） from day 6 to 10. CONCLUSIONS The change rules of VOCs in rat muscle are helpful for PMI estimation.
Animals ; Autopsy ; Gas Chromatography-Mass Spectrometry/methods* ; Muscles/pathology* ; Rats ; Solid Phase Microextraction ; Volatile Organic Compounds/chemistry*