Determination of cadmium in blood by use of atomic absorption spectroscopy with crucibles--and a rational procedure for dry-ashing.

A simple, minimal-reagent procedure for analysis of cadmium in blood is introduced. Blood samples from workers occupationally exposed to cadmium were collected with heparin. Titon X-100 surfactant was added, and 15-mul aliquots of the blood were pipetted into small nickel sampling cups and placed in a holder for 100 cups, which was enclosed in a stainless steel box. After the samples were dried and ashed in a muffle oven at various times and temperatures, cadmium was determined in an air/acetylene flame in an atomic absorption instrument with a deuterium arc background corrector. Absorbance measurements were made by signal-averaging facilities in the instrument. The conditions for analysis are specified. The method appears to be accurate and reproducible, with a CV of about 6% in the range 35-160 nmol/liter. The detection limit was 3.0 nmol/liter of blood. With the new procedure, many blood samples can be dried and ashed in parallel, which favors both simplicity and precision.