Occurrence of short chain aliphatic diols in human blood: identification by gas chromatography-mass spectrometry.

Patients attending a general hospital for various reasons were screened for raised serum gamma glutamyltransferase (gamma-GT) and positive blood alcohol concentration (BAC). The results served as objective biochemical tests of heavy drinking. Among 419 individuals, 50 (11.9%) met these requirements and blood samples were used to determine the presence of low molecular mass aliphatic diols. 1,2-Propanediol, 2,3-butanediol and 2,2-dimethyl-1,3-propanediol were determined by gas liquid chromatography-mass spectrometry (GC-MS). In patients with blood ethanol concentration less than 2 mmol/l, 1,2-propanediol and 2,2-dimethyl-1, 3-propanediol mainly occurred together at median concentrations of about 200 mumol/l. When blood ethanol was 2-42 mmol/1,2,3-butanediol was also present covering a wide concentration range: three patients had concentrations between 6 and 10 mmol/l. There was no apparent correlation between the concentration of 2,3-butanediol and the concentration of blood ethanol. The diols were below the limits of detection in blood from nonintoxicated control individuals and hospital in-patients.

High performance liquid chromatography and glass capillary gas chromatography of geometric and positional isomers of long chain monounsaturated fatty acids.

Positional and geometrical isomers of monounsaturated long chain fatty acids were analyzed by the combination of high performance liquid chromatography (HPLC) and glass capillary gas chromatography (GC). A preparative group separation ofcis andtrans isomers of the monounsaturated fatty acid methyl esters was achieved according to chain length by reversed-phase HPLC, and using a highly sensitive interference refractive index detector. After collection of the different fractions containingcis andtrans forms of the monounsaturated fatty acid methyl esters, the fractions were analyzed for their content of positional isomers using glass capillary GC with Silar-5 CP as stationary phase. The preparative step in the HPLC was also used analytically for the determination of the ratio between thecis andtrans monounsaturated fatty acids. A comparison was made between the results obtained with the HPLC technique and the results of a GLC technique with a packed OV-275 column. There was a good correlation between the 2 techniques with a tendency to highertrans values with the HPLC technique (4%). It was shown with reference substances that 18∶1ω6-cis to ω11-cis and 18∶1ω5-trans to ω12-trans, the most common monounsaturated fatty acid isomers in partially hydrogenated vegetable oils, could be almost quantitatively recovered in the HPLC step. Most of the individual positional isomers of monounsaturated fatty acids of varying chain length could be separated and determined in the glass capillary GC step with the exception of those isomers containing the double bond in a relatively high ω-position. The relative standard deviation of the technique as determined with reference substances was better than 4%. The described technique was applied to the analysis of the isomeric monounsaturated fatty acid content in partially hydrogenated vegetable and marine oils, and about 5 samples a day could be executed.