Rapid detection of chromium in different valence states in soil using resin selective enrichment coupled with laser-induced breakdown spectroscopy: From laboratory test to portable instruments

摘要

Hexavalent chromium (Cr(VI)) is toxic, but trivalent chromium (Cr(III)) is essential to organisms. Monitoring Cr (VI) and Cr(III) in soil can improve our understanding of Cr biogeochemistry and toxicity. However, it is difficult to rapidly determine Cr in different valences in soil using traditional methods. A new method, resin selective enrichment with laser-induced breakdown spectroscopy, for rapidly determining Cr in different valence states (total Cr, Cr(III), and Cr(VI)) in soil is presented here. The method effectively separated Cr(III) and Cr(VI). The regression coefficients for the total Cr, Cr(III), and Cr(VI) calibration curves were all > 0.99. The total Cr and Cr (VI) limits of detection were 19.34 and 35.18 mg/kg, respectively. The total Cr and Cr(VI) relative standard deviations for repeat analyses were 7.69% and 12.98%, respectively. A portable laser induced breakdown spectroscopy instrument for detecting Cr in soil, developed in our laboratory, gave a regression coefficient for the total Cr concentration in soil of 0.993. The results indicated that the method can rapidly and accurately quantify Cr in different valence states in soil. There is potential for miniaturizing the instrument to allow Cr to be determined in soil in the field