An assessment of contemporary atomic spectroscopic techniques for the determination of lead in blood and urine matrices

The preparation and validation of a number of clinical reference materials for the determination of lead in blood and urine is described. Four candida te blood lead reference materials (Lots, 047-050), and four candidate urine lead reference materials (Lots, 034, 035, 037 and 038), containing physiol ogically-bound lead at clinically relevant concentrations, were circulated to up to 21 selected laboratories specializing in this analysis. Results fr om two interlaboratory studies were used to establish certified values and uncertainty estimates for these reference materials. These data also provid ed an assessment of current laboratory techniques for the measurement of le ad in blood and urine. For the blood lead measurements, four laboratories u sed electrothermal atomization AAS, three used anodic stripping voltammetry and one used both ETAAS and ICP-MS. For the urine lead measurements, 11 la boratories used ETAAS (most with Zeeman background correction) and 10 used ICP-MS. Certified blood lead concentrations, +/- S.D., ranged from 5.9 +/- 0.4 mug/dl (0.28 +/- 0.02 mu mol/l) to 76.0 +/- 2.2 mug/dl (3.67 +/- 0.11 m u mol/l) and urine lead concentrations ranged from 98 +/- 5 mug/l (0.47 +/- 0.02 mu mol/1) to 641 +/- 36 mug/l (3.09 +/- 0.17 mu mol/l). The highest c oncentration blood lead material was subjected to multiple analyses using E TAAS over an extended time period. The data indicate that more stringent in ternal quality control practices are necessary to improve long-term precisi on. While the certification of blood lead materials was accomplished in a m anner consistent with established practices, the urine lead materials prove d more troublesome, particularly at concentrations above 600 mug/l (2.90 mu mol/l). (C) 2001 Elsevier Science B.V. All rights reserved.