Atomic absorption spectrophotometry (A.A.S.) flame techniques use 0·2-0·5 ml plasma. A.A.S. with Electrothermal atomisation is more sensitive and requires <20 μ1 of plasma, but contamination is a problem and interference from the plasma matrix prevents the use of aqueous standards. Therefore the zinc in sheep serum was removed with Chelex 100 and the residual zinc(<0·05 μg/m1) analysed by flame A.A.S. Zinc standards ranging from 0·1 to 2·0 μg/m1.Zn were prepared in this serum. Only acid washed glass, polypropylene or P.T.F.E. equipment was used. A single 50 μ1 Oxford pipette tip, once cleaned, was used to check the distilled water (<0·2ng/ml.Zn) and then for the whole days work, being rinsed in 5% Aristar HNO3×10 and H2×10 between injections. Standards and samples were diluted 1:200 by a Micromedic diluter into polypropylene tubes and 50 μ1 injections made into the furnace. Precision studies give a Coefficient of variation of 2·5%. Recovery experiments gave results 98 ± 2% of expected value with 95 ± 5% recovery of the amount added.
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Shaw, J., Bury, A., Barber, A. et al. MICROMETHOD FOR DETERMINATION OF PLASMA ZINC IN PRETERM INFANTS. Pediatr Res 14, 1420 (1980) doi:10.1203/00006450-198012000-00070