Direct determination of cadmium in urine with use of a stabilized temperature platform furnace and Zeeman background correction.

In this determination of Cd in urine, simple aqueous standards were used to which NaCl and the matrix modifier were added. The urine was diluted fivefold with water. The mean analytical recovery of added Cd for urine samples was 101%, with individual variations of less than 4%. We used the stabilized temperature platform furnace, Zeeman background correction, pyrolytically coated graphite tubes, and (NH4)2HPO4 plus HNO3 as a matrix modifier. The sensitivity of the method provided a characteristic amount of 0.35 pg of Cd per 0.0044 A X s, obtained with integrated absorbance readings. The absolute Cd detection limit in urine was 0.15 pg, corresponding to 0.04 microgram/L of urine. Lower relative detection limits for Cd in urine can be attained if the analytical situation demands it.