Electrothermal atomic absorption spectrometric-determination of cobalt in human serum and urine.

Problems and possibilities of the determination of Co in serum and urine samples by electrothermal atomic absorption spectrometry (ETAAS) are described. Optimal instrumental parameters as well as a suitable atomizer, calibration procedure and hydrogen peroxide as modifier are proposed for direct ETAAS measurement of Co in serum and urine. The detection limit achieved was 0.1 microg L(-1) for both matrices and relative standard deviations varied in the range 5-20% depending on the Co concentration in the sample. Validity of the method was verified by the analyses of standard reference materials. For serum samples with a Co content lower than the detection limit, a separation and preconcentration procedure based on liquid/liquid extraction is suggested prior to determination of Co in the organic phase by ETAAS. This procedure permits determination of 0.02 microg L(-1) Co in serum samples with a relative standard deviation of 10-18%.