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Background : The lung cancer incidence in Chinese women is among the highest in the world, but tobacco smoking accounts for only a minority of the cancers. Epidemiologic investigations of lung cancer among Chinese women have implicated exposure to indoor air pollution from wok cooking, where the volatile emissions from unrefined cooking oils are mutagenic. Purpose : This study was conducted to identify and quantify the potentially mutagenic substances emitted from a variety of cooking oils heated to the temperatures typically used in wok cooking. Methods: Several cooking oils and fatty acids were heated in a wok to boiling, at temperatures (for the cooking oils) that ranged from 240 °C to 280 °C (typical cooking temperatures in Shanghai, China). The oils tested were unrefined Chinese rapeseed, refined U.S. rapeseed (known as canola), Chinese soybean, and Chinese peanut in addition to linolenic, linoleic, and erucic fatty acids. Condensates of the emissions were collected and tested in the Salmonella mutation assay (using Salmonella typhimurium tester strains TA98 and TA104). Volatile decomposition products also were subjected to gas chromatography and mass spectroscopy. Aldehydes were detected using high-performance liquid chromatography and UV spectroscopy. Results : 1,3-Butadiene, benzene, acrolein, formaldehyde, and other related compounds were qualitatively and quantitatively detected, with emissions tending to be highest for unrefined Chinese rapeseed oil and lowest for peanut oil. The emission of 1,3-butadiene and benzene was approximately 22-fold and 12-fold higher, respectively, from heated unrefined Chinese rapeseed oil than from heated peanut oil. Lowering the cooking temperatures or adding an antioxidant, such as butylated hydroxyanisole, before cooking decreased the amount of these volatile emissions. Among the individual fatty acids tested, heated linolenic acid produced the greatest quantities of 1,3-butadiene, benzene, and acrolein. Separately, the mutagenicity of individual volatile emission condensates was correlated with linolenic acid content (r =.83 ; P =.0004). Condensates from heated linolenic acid, but not linoleic or erucic acid, were highly mutagenic. Conclusions : These studies, combined with experimental and epidemiologic findings, suggest that high-temperature wok cooking with unrefined Chinese rapeseed oil may increase lung cancer risk. This study indicates methods that may reduce that risk. Implications : The common use of wok cooking in China might be an important but controllable risk factor in the etiology of lung cancer. In the United States, where cooking oils are usually refined for purity, additional studies should be conducted to further quantify the potential risks of such methods of cooking. [J Natl Cancer Inst 87 :836-841, 19951

Pyrolysis coupled with gas chromatography and carbon dioxide supercritical fluid extraction/supercritical fluid chromatography was used to study the affect of pyrolysis temperature (500 or 999°C) and pyrolysis atmosphere (helium or carbon dioxide) on the resulting chromatographic profiles of asphaltenes. The use of the lower pyrolysis temperature yielded fewer and less volatile components than did the high pyrolysis temperature. This was supported by both gas chromatographic profiles and the profiles obtained after supercritical fluid extraction and chromatography. Fast atom bombardment/Mass spectrometry (FAB/MS) and Fourier Transform Infrared Spectrophotometric (FTIR) studies revealed, for these experiments, that although the pyrolysis process greatly altered the structure of the asphaltenes, the effect of the atmosphere present during pyrolysis appeared to have little affect on the fragments formed when these reactions were carried out at ambient pressure.

The design and application of a two dimensional gas-liquid chromatograph (gc) to the analysis of clofibrate in rabbit plasma is described. The assay involves three steps: extraction of plasma, derivatization with pentafluorobenzylbromide and dual gc analysis. Development time for an assay for drugs is considerably shortened as compared to conventional approaches using other chromatographic methods. Approximately 20 samples can be processed in a day.

Previous clinical studies have shown Oriental subjects to be significantly more sensitive to alcohol than Occidental subjects. The results of this study corroborated these findings: the 24 Oriental subjects tested showed significantly more skin flushing, increased heart rate, drop in blood pressure, and general discomfort with alcohol than the 24 Occidental subjects. In addition, the former more frequently reported family histories of flushing. The need for further studies to elucidate the mechanism is apparent. The evidence suggests that the low rates of alcohol abuse and alcoholism commonly found among Oriental people may have physiological rather than cultural origins.

This laboratory previously reported a radioimmunoassay (RIA) for aldosterone based on prior purification by solvent partitioning, periodate oxidation and a single thin-layer chromatogram. Other methods reported to date require paper chromatography to attain the required specificity. The method presented herein utilizes antibodies produced to aldosterone-γ-lactone 3-carboxymethyl oxime coupled to BSA. Aldosterone-γ-lactone constitutes the ligand. Overall interference is: cortisol 0.07%, corticosterone 0.02%, progesterone 0.17%, estradiol-ND, testosterone 0.02%, and 18-hydroxy corticosterone 0.29%. The purification procedure consists of CHCI3 extraction, benzene:H2O partition, periodate oxidation and bicarbonate wash. Recovery is determined from added 3H- or 14Caldosterone and is 40–50%. Simultaneous GC and RIA of urine samples (μg/24 hr) are: The correlation between GC and RIA methods is 0.95% (p < .01). RIA values with and without TLC showed no significant difference. This method is simple and reproducibl...

Combined gas—liquid chromatography mass-spectroscopy was used to identify lithocholic acid and confirm the presence of other bile acids in serum of a healthy fasting subject. GLC was used to measure deoxycholic (DCA), chenodeoxycholic (CDCA), and cholic (CA) acids in sera. Before analysis, serum bile acids were purified by (a) enzymatic hydrolysis of conjugates, (b) anion-exchange chromatography, (c) alumina adsorption chromatography, and (d) GLC of methyl trifluoroacetate derivatives on QF-1. Recovery of bile acids (determined by adding [14C]cholic acid to each sample), after correction for loss during purification, was 63-83%. Fasting values for 28 healthy subjects were: 1.4-46.5 (av 7.1), 1.4-49.6 (12.8), and 1.4-46.0 (16.0) µg/100 ml for DCA, CDCA, and CA, respectively. Traces of lithocholic acid were found in 20% of the cases studied. The smaller ranges we found for serum bile acid concentrations in a healthy fasting population are attributed to the careful health-screening of subjects and improved techniques.

The accuracy and reproducibility of gas—liquid chromatography of plasma amino acids as their n-butyl N-trifluoroacetyl esters are statistically evaluated. Plasma is deproteinized with picric acid and amino acids are purified by microcolumn chromatography on Dowex 50 W-X12. Routine analysis requires only 0.2 ml of plasma with recoveries of 75–90% for the protein precipitation—ion exchange steps as determined by tracer methods. The ester derivatives are injected directly onto 0.7% EGA or 1.0% OV-17 columns. Variability due to the use of different GLC columns is minimized by careful calibration. Replicate analysis of the same sample indicates that the overall reproducibility is satisfactory for clinical usuage. The range of normal concentration for amino acids in our clinical population is within agreement with values obtained by other methods. A complete analysis can be accomplished within 12 h, however grouping samples allows processing of 8–10 plasma samples in one working day, greatly facilitating biochemical investigations such as metabolic disorders in retarded children.