Preconcentration and determination of As, Cd, Pb and Bi using different sample introduction systems, cloud point extraction and inductively coupled plasma optical emission spectrometry

Abstract

This study deals with the development of a method for As, Bi, Cd and Pb preconcentration and determination using cloud point extraction (CPE) and inductively coupled plasma optical emission spectrometry (ICP OES). Hydride generation, pneumatic nebulization and micronebulization/aerosol desolvation were investigated for introducing the surfactant rich phase into the ICP. O,O-Diethyldithiophosphate (DDTP) was used as complexant and octylphenoxypolyethoxyethanol (Triton X-114) as surfactant. The influence of concentration of HNO₃, HCl, DDTP, Triton X-114, surfactant rich phase in methanol, reductant of As, and NaBH₄ was evaluated. The enrichment factors obtained were 10, 18, 12 and 14 for As, Bi, Cd and Pb, respectively. The limits of detection (LODs) of As, Bi, Cd and Pb were 0.055, 0.063, 0.047 and 0.28 μg L⁻¹, respectively. Precision and accuracy were assessed by analysis of certified enriched water (NIST 1643e), oyster tissue (NIST 1566b), tobacco leaves (CTA-OTL-1), bush branches and leaves (GBW 07602) and analyte spiking. Microwave-induced combustion (MIC), sonication, and acid digestion were used for sample preparation. The developed method was applied for extraction and determination of As, Bi, Cd and Pb in river water, wine, fertilizer and urine. Analyte recovery close to 100% and relative standard deviation (RSD) lower than 5% were observed.