Hexavalent Chromium Determination Using Diphenylcarbazide Coated Cellulose Technique

Rerngnaporn Mopoung, Aree Thanaboonsombut

Abstract


Diphenylcarbazide coated cellulose materials combined with UV-VISspectrophotometer were introduced as the simple detection method for quantitativedetermination of hexavalent chromium (Cr(VI)). The preparation of diphenylcarbazidecoated cellulose materials was, first, cut cellulose materials into small pieces sized 1 cm x 1cm, then, dip them into the 1,5-diphenylcarbazide solution (acetone) at the concentration of0.04 M and, finally, evaporate the coated materials in air. For the calibration curvepreparation, diphenylcarbazide coated cellulose materials were immersed in 25 mL of Cr(VI)solutions at pH 2 with concentrations ranging from 0 μg/L to 100 μg/L. The calibration curveobtained shows the relationship between the absorbance of Cr(VI)-diphenylcarbazidecomplexes and their concentrations. Additionally, the complex solutions developed differentcolor shades starting from colorless to pink-violet color according to their concentrations.The detection limit could be obtained at the concentration of 1.43 μg/L with sufficientprecision and accuracy. With this technique, color interferences from the presence of somesalts, i.e., NO3-, SO42-, PO43-, Na+, K+, Mg2+, Cl-, Al3+, Cu2+, Zn2+, Pb2+ and Fe3+, did notoccur at some particular salt concentrations with the Cr(VI) concentration at 100 μg/L. Itcould be concluded that the diphenylcarbazide coated cellulose technique is the simpledetection method for Cr(VI) determination and could be applied to quantify the concentrationof Cr(VI) in real samples, e.g., the extraction solution from plated-metallic sheet.

Keywords: simple detection, heavy metal, hexavalent chromium, on-site measurement


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