Ultrasound-assisted dispersive liquid-liquid microextraction for the speciation of traces of chromium using electrothermal atomic absorption spectrometry.
A microextraction procedure for the speciation of very low concentrations (0.005-0.2 µg L(-1)) of chromium is discussed. To the aqueous sample (10 mL), diluted hydrochloric acid, sodium chloride and a small amount of tributylphosphate (80 µL) are incorporated, and the mixture is submitted to ultrasounds for 10 min. The organic phase recovered after centrifuging is injected into the electrothermal atomizer, and the signal due to hexavalent chromium obtained. The repetition of the procedure using another aliquot in which all the chromium present is oxidized to Cr (VI) allows the Cr(III) content to be obtained by difference. The enrichment factor is 240 and the detection limit 0.002 µg L(-1) chromium. The relative standard deviation for ten consecutive microextractions of a 0.1 µg L(-1) chromium solution is close to 8%. The procedure is applied to waters and to the leachates obtained from low cost toys made of plastic materials.
Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30071 Murcia, Spain.
Ignacio
I
López-García
Marisol
M
Briceño
Yesica
Y
Vicente-Martínez
Manuel
M
Hernández-Córdoba
D002498:Centrifugation; D002857:Chromium / Q000737:chemistry / Q000302:isolation & purification*; D006851:Hydrochloric Acid; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D010755:Organophosphates; D012965:Sodium Chloride; D013010:Sonication; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
D010755:Organophosphates; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D012965:Sodium Chloride; C009524:tributyl phosphate; D006851:Hydrochloric Acid
Chromium; DLLME; Dispersive liquid–liquid microextraction; ETAAS; Speciation; Tributylphosphate; Ultrasounds; Waters