XXXX determination in serum and urine by electrothermal atomic absorption spectrometry.

@entity3406 @entity5022 @entity13373 @entity12141 @entity1953
@entity1953 determinations in biological fluids are of great interest in biological or toxicological research programs. Cobalturia is often chosen as an indicator for a biological monitoring program in occupational exposure to @entity1953 dusts. The method described here derives from the IUPAC reference method for @entity3406 determination. It enables cobaltemia and cobalturia to be measured in small samples (1 mL). The mean usual values for @entity1953 in biological fluids are very low (2.7 nmol @entity5022 for serum and 6.7 nmol @entity5022 for urine), and therefore, thus require an analytical procedure with preconcentration and extraction. The sample is mineralized by wet acid digestion. After digestion, inorganic @entity1953 is extracted in form of @entity13373 complex into @entity12141 and measured in the organic layer by electrothermal atomic absorption spectrometry. The analytical parameters are described in detail. The extraction output is about 99%. The detection limits are 1.93 and 1.89 nmol @entity5022 for serum and urine, respectively. Sensitivity (expressed as the concentration that gives a 0.044 absorbance) is 3.4 nmol @entity5022 for serum and 3.3 nmol @entity5022 for urine. Within-run precision ranged between 3.9 and 2.5% (coefficients of variation) for serum and 4.2 and 1.1% for urine, at 87 and 136 nmol @entity5022 levels, respectively. Between-run precision ranged between 4.3 and 3.3% (coefficients of variation) for serum and 4.2 and 2.3% for urine, at 87 and 136 nmol @entity5022 levels, respectively. At very low concentration, 5.7 nmol @entity5022 for serum and 2.5 nmol @entity5022 for urine, the between-run precision is, respectively, 19.5 and 28%. Linearity is effective between 0 and 272 nmol @entity5022 . Interferences and matrix effects are negligible for urine, serum, or plasma samples without hemoglobin. The method is easily applicable for routine determinations.
