SOLVENT-EXTRACTION OF CADMIUM AS A PREVIOUS STEP FOR ITS DETERMINATION IN BIOLOGICAL SAMPLES BY INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

A method is proposed for the solvent extraction of cadmium using 1,5-b is[1-(2-pyridyl)ethylidene] thiocarbonohydrazide (APTH) as extractant. The optimum extraction conditions were evaluated from a critical stud y of the effect of pH, concentration of extractant, shaking time and i onic strength. The maximum volume ratio of the aqueous to organic phas e was 25:1 for a single-stage extraction of 99-100% of the metal ion. The detection limit is 0.15 ng/ml cadmium, and the calibration is line ar from 0.2 to 500 ng/ml. The effect of interferences was studied and no interferences from the elements commonly found in biological materi als were observed. The extraction method was applied to the determinat ion of cadmium in some biological materials using inductively coupled plasma atomic emission spectrometry (ICP-AES).