Direct Determination of Trace Chromium in Biological Samples by Graphite Furnace Atomic Absorption Spectrometry with Slurry Introduction

A method for the direct determination of chromium in biological samples by Graphite Furnace Atomic Absorption Spectrometry with slurry sample introduction was proposed,and analytical conditions for determination were optimized.The sample was homogeneously suspended in 1.2 g·L-1 agar sol and injected into the graphite furnace by an auto-sampler,and chromium in the biological samples was determined directly using magnesium nitrate as a matrix modifier.Under the optimized experimental conditions,detection limit (3σ) of this method was found to be 0.5 μg·L-1.Linearity was kept between values of peak height and concentration of Cr(Ⅲ) in the range within 50 μg·L-1,corresponding to the linear regression equation of A=0.252 1 C+0.0311.Values of recovery found were in range of 98.6%-103.2%.