Ultra-sensitive determination of cyanide in surface water by gas chromatography-tandem mass spectrometry after derivatization with 2-(dimethylamino)ethanethiol

A gas chromatography-tandem mass spectrometric (GC-MS/MS) method has been established for the determination of cyanide in surface water. This method is based on the derivatization of cyanide with 2-(dimethylamino)ethanethiol in surface water. The following optimum reaction conditions were established: reagent dosage, 0.7 g L (1) of 2-(dimethylamino) ethanethiol; pH 6; reaction carried out for 20 min at 60 degrees C. The organic derivative was extracted with 3 mL of ethyl acetate, and then measured by using GC-MS/MS. Under the established conditions, the detection and quantification limits were 0.02 mu g L (1) and 0.07 mu g L (1) in 10-mL of surface water, respectively. The calibration curve had a linear relationship relationship with y = 0.7140x + 0.1997 and r(2) = 0.9963 (for a working range of 0.07-10 mu g L (1)) and the accuracy was in a range of 98-102%; the precision of the assay was less than 7% in surface water. The common ions Cl , F , Br , NO3 , SO42 , PO43 , K+, Na+, NH4 +, Ca2+, Mg2+, Ba2+, Mn4+, Mn2+, Fe3+, Fe2+ and sea water did not interfere in cyanide detection, even when present in 1000-fold excess over the species. Cyanide was detected in a concentration range of 0.07-0.11 mu g L (1) in 6 of 10 surface water samples. (C) 2014 Elsevier B. V. All rights reserved.