title: Cloud point extraction-flame atomic absorption spectrometry for pre-concentration and determination of trace amounts of silver ions in water samples.
abstract: A cloud point extraction (CPE) method was used as a pre-concentration strategy prior to the determination of trace levels of silver in water by flame atomic absorption spectrometry (FAAS) The pre-concentration is based on the clouding phenomena of non-ionic surfactant, triton X-114, with Ag (I)/diethyldithiocarbamate (DDTC) complexes in which the latter is soluble in a micellar phase composed by the former. When the temperature increases above its cloud point, the Ag (I)/DDTC complexes are extracted into the surfactant-rich phase. The factors affecting the extraction efficiency including pH of the aqueous solution, concentration of the DDTC, amount of the surfactant, incubation temperature and time were investigated and optimized. Under the optimal experimental conditions, no interference was observed for the determination of 100 ng·mL-1Ag+in the presence of various cations below their maximum concentrations allowed in this method, for instance, 50 μg·mL-1for both Zn2+and Cu2+, 80 μg·mL-1for Pb2+, 1000 μg·mL-1for Mn2+, and 100 μg·mL-1for both Cd2+and Ni2+. The calibration curve was linear in the range of 1-500 ng·mL-1with a limit of detection (LOD) at 0.3 ng·mL-1. The developed method was successfully applied for the determination of trace levels of silver in water samples such as river water and tap water.
authors.affiliation: College of Chemistry and Chemical Engineering, Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637000, China.
authors.forename: Xiupei
authors.initials: X
authors.lastname: Yang
authors.affiliation: College of Chemistry and Chemical Engineering, Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637000, China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Jia
authors.affiliation: College of Chemistry and Chemical Engineering, Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637000, China.
authors.forename: Xiaocui
authors.initials: X
authors.lastname: Yang
authors.affiliation: College of Chemistry and Chemical Engineering, Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637000, China.
authors.forename: Gu
authors.initials: G
authors.lastname: Li
authors.affiliation: Exposure and Biomonitoring Division, Health Canada, 50 Colombine Driveway, Ottawa K1A 0K9, Canada.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Liao
keywords: Cloud point extraction; Flame atomic absorption spectrometry; Silver ions