Sensitive determination of acetonitrile and propionitrile in human whole blood by headspace capillary gas chromatography with cryogenic oven trapping

We have developed a simple and sensitive method for determining acetonitrile and propionitrile in human whole blood using capillary gas chromatography (GC) with cryogenic oven trapping. After heating 0.5 ml of a whole blood sample containing both nitriles and 0.5 ml of distilled water in a 7-ml vial at 75°C for 15 min, 5 ml of the headspace vapor was drawn into a 10-ml syringe and injected to GC with a flame thermionic detector. A sharp peak was obtained for acetonitrile at -10°C of the initial oven temperature. The extraction efficiencies for acetonitrile and propionitrile were 0.27 and 0.40%, respectively. For quantitation of acetonitrile, propionitrile was used as internal standard, and vise versa. The calibration curves for both compounds gave good linearity in the range of 0.2-6 μg/ml whole blood. The detection limits (signal to noise ratio = 3) were 0.05 μg/ml for acetonitrile and 0.01 μg/ml for propionitrile. The coefficients of intra-day variations were 1.0% at 0.4 μg/ml and 1.7% at 2 μg/ml for acetonitrile; 7.1 % at 0.4 μg/ml and 1.0% at 2 μg/ml for propionitrile. This method can be applicable for determining these nitriles in whole blood samples in acute and chronic intoxication cases.