Graphite furnace atomic absorption spectrometric determination of blood lead with palladium modification

RESUMO

In this work we present a graphite furnace atomic absorption spectrometric method for blood lead using palladium as a chemical modifier. Whole blood was diluted 10- fold with a 0.1% v/v triton X-100 solution; 10*L of this solution and 10*L of the palladium-based modifier (2mg Pd/L, 2% w/v citric acid and 0.01 M nitric acid) were injercted onto the l'vov platform by using the alternate volume mode. The following furnace operating parameters were used (a) drying steps, 120-C for 10s and 250-C for 30s; (b) pyrolisis steps, 800-C for 45s (with oxygen) and 1100-C for 25s; (c) atomization, 1600-C for 3s; (d) clean out, 2700-C for 4s. Accuracy was tested by using (i) a NIST standard (SRM-909) and the Behring Control Blood for Metal 1 (OSSD 21) with lead concentrations of 23.7 ñ 0.7 *g/L) and 413 ñ 51 *g/L (found 407 ñ 6 *g/L) respectively; (ii) recovery studies (ca. 100 ñ 1%), and (iii) a reported method (meadf relative error 5.1%). Approximate standard deviations of 0.3 (within-run) and 0.7 (between-runs) *g Pb/L were found in the precision study. The detection limit (3*) and the characteristic mass (for a 10- *L injection volume) were 0.1 *g Pb/L and 15 pg/0.0044A*s, respectively. The proposed method was used to establish the lead levels of patients with renal insuficiency; a mean concentration (ñ SD) of 59 ñ 39 *g Pb/L (range 12 - 160 *g Pb/L) was found. The method was interference-free, reliable and reproducible