Gas chromatography for measurement of chlorpyrifos in serum

To investigate the method for the measurement of chlorpyrifos in serum by gas chromatography, and to provide a basis for emergency treatment of poisoning in clinical practice.Venous blood (3.0 ml) was collected from patients. After coagulation, the blood samples were centrifuged at 4 000 r/min for 5 minutes, and 0.5 ml of serum was placed in a glass test tube with a cork; 4.0 ml of ethyl acetate was then added and mixed rapidly, and this solution was subjected to extraction for 5 minutes and centrifuged at 4 000 r/min for 10 minutes. The ethyl acetate layer was placed in a conical tube and extracted twice with the same method. The extract was mixed and blow-dried with nitrogen, and the residue was dissolved with 50.0 μl ethanol. Gas chromatography was used for measurement, with a sample size of 1 μl and a retention time of 9.609 minutes.The linear range of this method was 0.2~20.0 μg/ml, and the regression equation was y=2 372.6x+357.2(r=0.999 6). The detection limit of chlorpyrifos in serum was 0.05 μg/ml, and the recovery rate was 84.6%~102.4%. The relative standard deviation was 3.6%~4.8%, and the intra-day and inter-day relative standard deviations were 3.62%~5.10% and 3.77%~4.98%, respectively.This detection method is accurate, simple, and convenient, and can be used for the clinical diagnosis of chlorpyrifos poisoning.