title: Speciation of arsenic (III) and arsenic (V) based on quenching of CdS quantum dots fluorescence using hybrid sequential injection-stopped flow injection gas-diffusion system.
abstract: A hybrid sequential injection-stopped flow injection system was developed for the speciation of arsenic based on the quenching of mercaptoacetic acid capped cadmium sulfide quantum dots (CdS-MAA QDs) fluorescence intensity. The analytical procedure involves the generation of arsine from As(III) by sodium borohydride in acetate buffer medium pH 6.0. The generated arsine (donor stream) diffuses across the PTFE membrane of the gas-diffusion unit into an acceptor stream and then interacts with CdS-MAA QDs. Total arsenic was determined after pre-reduction of As(V) to As(III) with 1% (m/v) mercaptoacetic acid. Concentration of As(V) in the sample solutions can be deduced from the difference of total arsenic and As(III). Optimization of the experimental conditions and instrumental parameters were investigated. Under optimal conditions, limits of detection were 20 μg L(-1) for As(III) and 40 μg L(-1) for As(V). Recoveries in the range 84-103% were obtained from sediment sample.
authors: Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors: Nutthaya
authors: N
authors: Butwong
authors: Supalax
authors: S
authors: Srijaranai
authors: Wittaya
authors: W
authors: Ngeontae
authors: Rodjana
authors: R
authors: Burakham
mesh_terms: D000085:Acetates / Q000737:chemistry; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D001894:Borohydrides / Q000737:chemistry; D002021:Buffers; D019187:Cadmium Compounds / Q000737:chemistry*; D002138:Calibration; D004058:Diffusion; D017022:Flow Injection Analysis / Q000379:methods*; D005453:Fluorescence; D005740:Gases / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry*; D013864:Thioglycolates / Q000737:chemistry; D013997:Time Factors
chemical_list: D000085:Acetates; D001894:Borohydrides; D002021:Buffers; D019187:Cadmium Compounds; D005740:Gases; D013440:Sulfides; D013864:Thioglycolates; C034939:cadmium sulfide; C017487:2-mercaptoacetate; C025364:sodium borohydride; D001151:Arsenic