Capillary Blood Collection by Paper for Lead Analysis by Graphite Furnace Atomic Absorption Spectrometry

A lead testing method is described that utilizes fingerstick capillary blood collected on Schleicher & Schuell 903 paper. The dried blood is eluted by treatment with 5% v/v nitric acid-0.75% v/v Triton X-100 to yield an aqueous solution for analysis, so that neither burning nor acid digestion of the paper is needed. Measurement of the lead in the eluted solution is done by graphite furnace atomic absorption spectrometry (GFAAS). The proposed method is not quantitative and must be used only for screening purposes. An initial comparison was made with venipuncture samples assayed for blood lead by a revised matrix modifier method adapted from Parsons and Slavin ( Spectrochim. Acta Part B, 1993, 48, 925-939). The blood samples were spotted on paper and assayed by the proposed method to give a correlation of r = 0.993 ( n = 39). A parallel study of 100 samples of capillary blood obtained by a fingerstick and corresponding venipuncture samples assayed by a matrix modifier method showed a correlation of r = 0.973 ( n = 100). The ease of transporting samples collected on paper and the relatively more pleasant means of obtaining blood from young children by fingerstick are other advantages. Thus, the proposed method offers another approach to processing blood samples for lead screening by atomic absorption spectrometry.