Determination of cadmium in biological samples by inductively coupled plasma atomic emission spectrometry after extraction with 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide
An inductively coupled plasma atomic emission spectrometric method for the determination of trace amounts of cadmium after extraction of the metal into isobutyl methyl ketone containing 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide is described. The optimum extraction conditions were evaluated from a critical study of the effects of pH, concentration of extractant shaking time and ionic strength. The detection limit for cadmium is 0.1 ng ml–1 and the calibration is linear from 0.2 to 140 ng ml–1. The relative standard deviation for ten replicate measurements is 2.9% for 2 ng ml–1 of cadmium. Results from the analysis of some certified biological reference materials are given.