Determination of serum copper by atomic absorption, with use of the graphite cuvette.

We have established and evaluated a flameless graphite cuvette method for copper in serum. This atomic absorption method provides substantial improvement in sensitivity, adequate accuracy, and acceptable precision, and little sample preparation is required before the analysis. Standard addition studies and measurements of National Bureau of Standards materials indicated that the proposed method is accurate, but that sample pH must be kept between 2 and 3 for high accuracy. Cations and anions that frequently are present in protein-containing samples do not interfere significantly. Sample cross contamination in the syringe must be carefully avoided. Finally, when results for more than 100 patients' sera by this method were compared to those obtained by flame atomic absorption for the same samples, no substantial bias or inaccuracies could be attributed to this new micro-scale method for serum copper. Hence, this method is ideally suited for use on pediatric patients.