In Vivo Preperation of Standard Reference Materials of Lead in Blood

Chung, K C; Choi, H C

Abstract

This report describes a preperation and characterization of canine blood lead(pb) standard reference material(SRM). Three adult beagle dogs(A, B, and C)were orally dosed with gelatin capsules containing pb(No3)2, equivalent to 10~80mg Pb/kg body weight. Blood was drawn 24 hours after the dose from the cephalic vein into lead free 500ml Pyrex beaker in which EDTA.K was contained as an anticoagulant. The amount of lead given to individual dog was varied arbitrarily. Three month later, 3 canine animals were orally dosed with lead secondarily to make mixed SRM(Dl) which was mixed different concentrations of lead in bloods with Al, B1, and C1 in vitro. The SRMs for A, B, C, Al, Bl, Cl, and Dl were distributed 2ml each into more than 300 lead free bottles, and were stored in refrigerator at 4 degrees C. The amount of lead in canine whole blood samples were determined using a Varian 30A atomic absorption spectrophotometer(AAS) with a model GTA-96 graphite tube atomizer with D2 background correction and a Hitachi Z-8100 AAS with Zeemaan background correction. The sensitivity and detection limits for lead determination of varian 30A were 0.46 microgram/L,0.34 microgram/L, and 0.56 microgram/L,0.14 microgram/L of Hitachi Z-100, respectively. Day to day variations in determination of blood lead concentration in a certain sample were 31.11+/-1.36 microgram/100ml by Varian 30A, and 33.08+/-0.82/100ml by Hitachi Z-8100, show ing the difference of 3% between the two results. At the blood lead concentrations of 56.31+/-1.98 microgram/100ml(A), 40.89+/-0.80 microgram/100ml(B), 59.01+/-1.38/100ml(C), the precisions of replicated measurements by AAS were 3.52%, 1.96%, and 2.34% respectively. Coefficient variation(CV) of SRMs(A, B, and C) within a standard sample were ranged from 0.92% to 7.50%, and those between 5 standard samples were l.21%, 2.64%, and 1.11%, respectively, showing inter-vial variation of 1 microgram/100ml. Lead levels in SRMs during one month storage were unchanged. The overall recoveries were 89.6-100.4%, 91.6-101.9%, 90.3-100.0% for A, B, and C SRMs, means were 56.46+/-2.69 microgram/100ml, 39.35+/-1.89 microgram/100ml, 57.40+/-2.31 microgram/100ml, and measurement ranges were 52.88-59.26 microgram/100ml, 37.47-41.68 microgram/100ml, 54.80-60.69 microgram/100ml, respectively. Those results were laid within confidence limits values. The lead concentrations in the mixed sample(Dl) stored over one month period were ranged from 32.76 microgram/100ml to 33.54/100ml, with CV ranging from l.2% to 2.7%. The results were similar to each of single samples(Al, Bl, and Cl) in respect of homogeneity and stability. Results of the mixed blood sample analysed after 1 month storage at 4 degrees C by four other laboratories(Ll, L2, L3, L4) were similar with those of our laboratory(L5 ;31.18+/-0.24 microgram/100ml, acceptable range by CDC; 25.18-37.18 microgram/100ml), showing the concentrations of 25.91+/-1.19 microgram/100ml(L1), 34.16+/-0.22 microgram/100ml(L2), 35.68+/-0.85 microgram/100ml(L3), 30.95+/-0.46 microgram/100ml(L4) in a each samples.