Evaluation of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry for direct determination of chromium in medicinal plants

Abstract

A method for Cr determination in medicinal plants using direct solid sampling graphite furnace high-resolution continuum source atomic absorption spectrometry was developed. Modifiers were dispensable. Pyrolysis and atomization temperatures were 1500°C and 2400°C, respectively. Slopes of calibration curves (50–750pg Cr, R2>0.999) using aqueous and solid standards coincides in 96%, indicated feasibility of aqueous calibration for solid sampling of medicinal plants. Accuracy was checked by analysis of four plant certified reference materials. Results were in agreement at 95% confidence level with certified and non-certified values. Ten samples of medicinal plants were analyzed and Cr contents were in the 1.3–17.7μgg−1 Cr range. The highest RSD (n=5) was 15.4% for the sample Melissa officinalis containing 13.9±2.1μgg−1 Cr. The limit of detection was 3.3ngg−1 Cr.