Radioimmunological screening and gas chromatographic identification of diazepam in blood and serum.

A radioimmunoassay for the determination of diazepam in human blood and serum is presented. Diazepam is separated from the bulk of the biological material by adsorption at Amberlite XAD-2 and subsequent desorption with ethyl acetate. The extract thus obtained can be used directly for the determination od diazepam by radioimmunoassay and gas chromatography with electron capture detection. For the combined radioimmunological and gas chromatographic determination 0.5 ml of blood or serum are necessary, the lower detection limit being approx. 5 ng/ml for both of these procedures. A good reliability of the radioimmunoassay is established with respect to precision, accuracy and specificity. The quantitative results obtained by radioimmunoassay and gas chromatography correspond well with each other. The radioimmunological procedure enables the screening of more than 200 samples for diazepam by one technician within two working days.