A novel strategy for chromium speciation at ultra-trace level by microsample injection flame atomic absorption spectrophotometry

• Published in: Journal of analytical atomic spectrometry 2012-01, Vol.27 (9), p.159-1517
• Main Authors: Baig, Jameel Ahmed, Hol, Aysen, Akdogan, Abdullah, Kartal, Aslihan Arslan, Divrikli, Umit, Kazi, Tasneem Gul, Elci, Latif
• Format: Article
• Language: English
• Subjects: Atomic absorption analysis; Carbon tetrachloride; Chromium; Ethyl alcohol; Mathematical analysis; Optimization; Solvents; Speciation
• ISSN: 0267-9477; 1364-5544
• DOI: 10.1039/c2ja30107e

Simple, robust and novel analytical procedures were developed for the speciation of chromium by carrier element co-precipitation (CECP) and dispersive liquid-liquid microextraction (DLLME) coupled with microsample injection system-flame atomic absorption spectrophotometry (MIS-FAAS). Ammonium pyrrolidine dithiocarbamate (APDC), carbon tetrachloride and ethanol were used as chelating agent, extraction solvent and disperser solvent, respectively for the determination of Cr( vi ) by DLLME. For total chromium, Cr( iii ) was oxidized by Ce(SO 4 ) 2 in acidic media (0.07 mol L 1 H 2 SO 4 ) and the resulting solution was co-precipitated with APDC. The concentration of Cr( iii ) was estimated by determining the difference between the concentration of total chromium and that of Cr( vi ). The maximum recovery of Cr( vi ) was obtained with DLLME at optimal conditions of pH 3.0 , 0.25% APDC, 100 L CCl 4 , 1.00 mL of CH 3 CH 2 OH and 0.01 mg L 1 Cr( vi ). Whereas, the optimal conditions for CECP were 40 mL initial volume of water samples, 0.25% APDC, 0.02% Ce(SO 4 ) 2 and 0.10 mg L 1 Cr( vi ) concentration. The limits of detection and enrichment factor of DLLME and CECP were [0.037 and 2.13] and [400 and 100] g L 1 , respectively with 40 mL initial volumes. The relative standard deviations (RSD, n = 6) were