Ultrasonic-assisted Supramolecular Solvent Liquid-liquid Microextraction for Inorganic Chromium Speciation in Water Samples and Determination by UV-Vis Spectrophotometry
Nebiye Ozkantar, Mustafa Soylak, Mustafa Tüzen
Abstract
A simple and fast ultrasonic-assisted green supramolecular solvent liquid-liquid microextraction method (UA-SS-LLME) was developed for the determination of Cr(VI) and Cr(III). A Cr(VI) stock solution was complexed with 1,5-diphenylcarbazide (DPC) reagent to form a metal ligand reaction, followed by UV-Vis spectrophotometric analysis at 540 nm. Tetrahydrofuran (THF) and decanoic acids were also used for the microextraction of chromium speciation. Cr(III) was oxidized to Cr(VI) by using H 2 SO 4 for the determination of total chromium. The Cr(III) concentration was calculated by subtracting the Cr(VI) concentration from total chromium. The parameters for sample volume, H 2 SO 4 concentration, DPC concentration, and ultrasonic bath time were optimized at 20 mL, 0.002 mol L -1 , 1.2510 -4 mol L -1 , and 4 min, respectively. The interference effects of the matrix components were also examined. The limit of detection (LOD), limit of quantification (LOQ), enhancement factor, and the relative standard deviation were found at 0.79 g L -1 , 2.64 g L -1 , 50 and 2.40 %, respectively. The accuracy of the method was verified by analyzing two certified reference materials (TMDA-64.2 Fortified Lake Water and TMDA-53.3 Fortified Environmental Water). The proposed method was successfully used to the analysis of real environmental waters.