Rapid analysis of nickel in urine by electrothermal atomic absorption spectrophotometry

A method is described for analysis of nickel in urine, which involves dilution of urine with dilute nitric acid and direct quantitation of nickel by electrothermal atomic absorption spectrophotometry with Zeeman background correction. The detection limit for nickel is 0.5 micrograms per L of urine; the coefficient of variation of replicate determinations is 4 to 5 percent (within-run) and 6 percent (run-to-run). Recovery of nickel added to urine (20 micrograms per L) averages 99 +/- 5 percent (mean +/- SD). Analytical results agree closely with measurements by the International Union of Pure and Applied Chemistry (IUPAC) reference procedure (correlation coefficient = 0.99). Nickel concentrations in urine specimens from 34 non-exposed, healthy, adult persons living in Connecticut average 2.0 +/- 1.5 microgram per L (range = 0.5 to 6.0 micrograms per L). Urine nickel concentrations are directly correlated with urine creatinine concentrations and specific gravity measurements. Elevated concentrations of nickel are observed in urine specimens from nickel-exposed workers, including nickel electroplating workers (mean = 27 micrograms per L, range = 3.1 to 82 micrograms per L, N = 19) and nickel battery workers (mean = 32 micrograms per L, range = 2.8 to 103 micrograms per L, N = 7). This method is more rapid and convenient than previous techniques and is suitable for routine use in clinical and industrial laboratories.