Determination of Heavy Metals in the Plant Sample Pretreatment Methods

Abstract

In this paper, dry ashing method, mixed acid nitration (H2SO4-H2O2), three acid digestion (HNO3-H2SO4-HClO4) and aqua-regia-HClO4 these four test solution preparation method on the decomposition of plant standards GBW07603 processing, use atomic absorption spectrophotometry Zn, Cu, Pb, Fe, Cd, Cr six kinds of metal elements, and the measured values compared with the standard value. The results showed that after dry ashing recoveries higher than Zn recovery after acid digestion; Cu determination should not use dry ashing; Pb determination should not be used mixed acid nitration (H2SO4-H2O2) or tri-acid digestion method (HNO3-H2SO4-HClO4);dry ashing treatment after acid digestion Cr yield higher Cr recoveries. Comprehensive analysis of the low carbon content of the metal elements in plant samples (Zn, Cu, Pb, Fe, Cd, Cr) of the measurement, can be aqua-regia-HClO4 pretreatment method, and for comparing the carbon content high plant samples should be used as a dry ashing pretreatment method. That is, different pretreatment methods for the determination of different analyte have a certain impact.