[Determination of serum copper and zinc in different chemical forms by graphite furnace atomic absorption spectrometry with ethanol-EDTA precipitation method].

A simple and reliable method was developed for the determination of serum copper and zinc in different chemical forms by graphite furnace atomic absorption spectrometry (GFAAS) with ethanol-EDTA precipitation. The serum and ethanol were mixed with volume ratio 1 : 2. The mixture was incubated at 70 degrees C and ultra-centrifuged to precipitate proteins. Zinc and copper can be released from albumin after EDTA treating. Thus, macroglobulin-zinc, ceruloplasmin-copper, and albumin-bound zinc or copper could be determined by two proposed precipitation steps. The determination limit of copper (3sigma) was 1.2 microg x L(-1) and the recovery was 92.3%-104%, while the determination limit of zinc (3sigma) was 0.098 microg x L(-1), and the recovery was 90%-107%. This two-step precipitation method can be used to determine serum zinc and copper in various chemical forms in tumor, Wilson patients and heathy human.