INDIRECT DETERMINATION OF THIOCYANATE IN BIOLOGICAL-FLUIDS USING ATOMIC-ABSORPTION SPECTROMETRY

The method involves: the complexation of thiocyanate with the Schiff base complex of copper, [Cu(BPTC)]+, where BPTC is 2-benzoyl pyridine thiosemicarbazone; extraction of the complex into isoamyl acetate solvent within the pH range 5.2-9.0; aspirating the organic phase into flame AAS; and measuring the copper signal at 324.7 nm and hence indirectly measuring the thiocyanate concentration. The method applied in biological fluids involves deproteinization for saliva and serum, and centrifugation for urine prior to its determination. The method proposed is free from most interferences due to metal ions, anions and organics. The limit of detection (3-sigma) value is 4 ng ml-1 with a sensitivity of 4 X 10(-4) ml-mu-g-1 and relative standard deviation of 1.8% for six blank determinations. Recoveries of 96-102% of 10-mu-g SCN- added to different biological fluids were obtained.