title: Determination of chromium(III) in water by solid-phase microextraction with a polyimide-coated fiber and gas chromatography-flame photometric detection.
abstract: A method for the determination of trace Cr(III) in aqueous solution by solid-phase microextraction (SPME) coupled with gas chromatography (GC)-flame photometric detection (FPD) was developed. Aqueous Cr(III) was first converted to the volatile chromium trifluoroacetylacetonate (Cr(tfa)3) by derivatization with 1,1,1-trifluoroacetylacetone (Htfa), followed by SPME extraction using a polyimide-coated silica fiber. The distribution constants (K) of derivatized cis- and trans-Cr(tfa)3 between the polyimide phase and aqueous phase were 2012 and 2214, respectively. The two Cr(tfa)3 isomers extracted can be efficiently separated by a DB-210 GC column within 9 min. Selective detection of Cr was performed by a FPD equipped with a 385-nm long-pass filter. Linearity (r> 0.99) over the concentration range 5-300 ng ml(-1) Cr was obtained and the limit of detection was 2 ng ml(-1) Cr. The relative standard deviation was 7% at 10 ng ml(-1) Cr (n = 5). Applicability of this method to water analysis was tested by analyzing the chromium content in a reference standard water sample and an industrial effluent.
authors.affiliation: Department of Chemistry, Tunghai University, Taichung 40704, Taiwan.
authors.forename: Tzuoo-Huei
authors.initials: TH
authors.lastname: Ding
authors.forename: Huang-Huei
authors.initials: HH
authors.lastname: Lin
authors.forename: Chen-Wen
authors.initials: CW
authors.lastname: Whang
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D002857:Chromium / Q000032:analysis*; D007094:Imides / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007094:Imides; D014874:Water Pollutants, Chemical; D002857:Chromium