Determination of zinc and copper in urine using Zeeman effect flame atomic absorption spectroscopy

Zinc and copper were determined in urine using polarized Zeeman effect flame atomic absorption spectrophotometry. For the zinc assay, urine was diluted 1/10 with deionized water. Concentrations could be determined by comparison to standards in a salt matrix or in a commercial urine control. The linearity of the assay was 350 micrograms/l, the detection limit was 1.2 micrograms/l and the within-run relative standard deviation (RSD) was 2.08%, 3.06%, 0.71% and 1.29% for specimens with zinc concentrations of 202 micrograms/l, 206 micrograms/l, 1 003 micrograms/l and 1 032 micrograms/l, respectively. The between-run RSD was 2.34% for a mean zinc concentration of 461 micrograms/l. For the copper assay, urine was aspirated directly and concentrations were determined by standard additions. The linearity of the assay was 5 000 micrograms/l, the detection limit was 4.6 micrograms/l and the within-run RSD was 24.49%, 16.10%, 4.00% and 3.19% for specimens with copper concentrations of 9.8 micrograms/l, 11.8 micrograms/l, 50.0 micrograms/l and 50.2 micrograms/l, respectively. The between-run RSD was 8.78% and 4.72% for specimens with copper concentrations of 21.1 micrograms/l and 40.3 micrograms/l, respectively.