title: Three-phase solvent bar micro-extraction as an approach to silver ultra-traces speciation in estuarine water samples.
abstract: Silver ion inputs into the environment due to human activities have been increased in the last years because it has been used as a bactericide with application in medical, homecare and self-care products. In addition, it is toxic at low concentration for aquatic organisms. In estuarine waters, salinity and dissolved organic matter (DOM) regulate Ag(+) concentration by the formation of complexes as AgCln((n-1)-) and Ag-DOM. Difficulties of Ag(+) analysis in estuaries are associated to its low concentration level and interferences of sample matrix. Liquid and solid phase extraction methods have been used for speciation of silver in waters; however, miniaturized methods that offer a better environmental profile are desirable. Hollow fiber liquid phase micro-extraction (HFLPME) allows obtaining higher pre-concentration factors with a reduction of waste generation. Notwithstanding, some operational improvements are needed to permit their use as a routine method that can be afforded using a configuration of three-phase solvent bar micro-extraction (3PSBME). In this work, tri-isobutylphosphine sulphide (TIBPS) has been used as an extractant for Ag(+) pre-concentration in estuarine waters by 3PSBME. Under optimized conditions, Ag(+) has been pre-concentrated 60 times and the method presents a limit of detection of 1.53 ng L(-1). To evaluate which Ag species is transported by TIBPS, Cl(-) and DOM have been added to synthetic samples. As a result, a decrease in Ag pre-concentration efficiency after additions has been observed and quantified. Results showed that Ag(+) is selectively transported by TIBPS from estuarine water samples after comparison of the results with those obtained by the reference method of liquid extraction with APDC/DDDC.
authors.affiliation: Department of Analytical Chemistry. Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain. Electronic address: joseantonio.lopezlopez@uca.es.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: López-López
authors.affiliation: Department of Analytical Chemistry. Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Herce-Sesa
authors.affiliation: Department of Analytical Chemistry. Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Moreno
mesh_terms: D002244:Carbon / Q000737:chemistry; D011232:Chemical Precipitation; D002712:Chlorides / Q000737:chemistry; D004396:Coloring Agents / Q000302:isolation & purification*; D063366:Estuaries; D006801:Humans; D057230:Limit of Detection; D010720:Phosphines / Q000737:chemistry*; D018030:Silver Compounds / Q000302:isolation & purification*; D052616:Solid Phase Extraction / Q000379:methods*; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D002712:Chlorides; D004396:Coloring Agents; D010720:Phosphines; D018030:Silver Compounds; D014874:Water Pollutants, Chemical; D002244:Carbon
keywords: Estuary; Silver; Speciation; Three-phase solvent bar micro-extraction; Trace analysis