title: Speciation of As(III) and As(V) in water samples by graphite furnace atomic absorption spectrometry after solid phase extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic drop.
abstract: A solid phase extraction (SPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method, using diethyldithiphosphate (DDTP) as a proper chelating agent, has been developed as an ultra preconcentration technique for the determination of inorganic arsenic in water samples prior to graphite furnace atomic absorption spectrometry (GFAAS). Variables affecting the performance of both steps were thoroughly investigated. Under optimized conditions, 100mL of As(ΙΙΙ) solution was first concentrated using a solid phase sorbent. The extract was collected in 2.0 mL of acetone and 60.0 µL of 1-undecanol was added into the collecting solvent. The mixture was then injected rapidly into 5.0 mL of pure water for further DLLME-SFO. Total inorganic As(III, V) was extracted similarly after reduction of As(V) to As(III) with potassium iodide and sodium thiosulfate and As(V) concentration was calculated by difference. A mixture of Pd(NO3)2 and Mg(NO3)2 was used as a chemical modifier in GFAAS. The analytical characteristics of the method were determined. The calibration graph was linear in the rage of 10-100 ng L(-1) with detection limit of 2.5 ng L(-1). Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 80 ng L(-1) of As(ΙΙΙ) were 6.8% and 7.5%, respectively. The method was successfully applied to speciation of As(III), As(V) and determination of the total amount of As in water samples and in a certified reference material (NIST RSM 1643e).
authors.affiliation: Department Chemistry, Razi University, Kermanshah, Iran. Electronic address: mshamsipur@yahoo.com.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Shamsipur
authors.affiliation: Department Chemistry, Razi University, Kermanshah, Iran; Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address: nazirfatahi@yahoo.com.
authors.forename: Nazir
authors.initials: N
authors.lastname: Fattahi
authors.affiliation: Quality Control Department, Daana Pharmaceutical Company, P.O. Box 501575-5181, Tabriz, Iran.
authors.forename: Yaghoub
authors.initials: Y
authors.lastname: Assadi
authors.affiliation: Department Chemistry, Razi University, Kermanshah, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Sadeghi
authors.affiliation: Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Kiomars
authors.initials: K
authors.lastname: Sharafi
mesh_terms: D001151:Arsenic / Q000032:analysis* / Q000302:isolation & purification; D002614:Chelating Agents / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D052616:Solid Phase Extraction / Q000379:methods*; D012997:Solvents; D013054:Spectrophotometry, Atomic / Q000379:methods*; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002614:Chelating Agents; D012997:Solvents; D014874:Water Pollutants, Chemical; D014867:Water; D006108:Graphite; D001151:Arsenic
keywords: Arsenic speciation; Dispersive liquid–liquid microextraction; Graphite furnace atomic absorption spectrometry; Solid-phase extraction; Water analysis