title: Coupling of non-selective adsorption with selective elution for novel in-line separation and detection of cadmium by vapour generation atomic absorption spectrometry.
abstract: Non-selective adsorption of Cd(2+) ions on a cation exchange fiber and subsequent selective elution with a KI solution has been strategically utilized to develop a highly selective in-line separation of Cd(2+) ions from other metal ions for its rapid and reliable quantification by cold vapour-atomic absorption spectrometry. After retention of Cd(2+) with a high efficiency on cation exchange fiber, selective elution of the retained Cd(2+) was subsequently accomplished with 0.3M KI. Vapour generation of Cd for in-line CV-AAS determination was then achieved by merging the eluate with HCl and NaBH4. Interferences from most base metals with the vapour generation of Cd were eliminated by this approach, with the exception of Pb(2+)ions which was removed by co-precipitation with BaSO4 prior to the in-line separation. Substantial improvement in sensitivity of the in-line CV-AAS determination of Cd was achieved by increasing the sample loading time. A detection limit of 0.6 ng L(-1) (3σ) was obtained with sample loading time of 120 s, corresponding to a consumption of 24 mL of sample solution. Application of the method to the determination of Cd in certified sediment and fish samples gave a good agreement with the certified values. Further validation by recovery study in real fish sample digests and water gave average Cd recoveries of 98.7±1.0% for fish and 92±3% for water with RSD of 1.5% for fish and 4% for water, respectively.
authors.affiliation: NanoScience and Sensor Technology Research Group, School of Chemistry, Monash University, Clayton, Victoria 3800, Australia; School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: NanoScience and Sensor Technology Research Group, School of Chemistry, Monash University, Clayton, Victoria 3800, Australia. Electronic address: Sam.Adeloju@monash.edu.
authors.forename: Samuel B
authors.initials: SB
authors.lastname: Adeloju
keywords: Atomic absorption spectrometry; Cadmium; Cation exchange; Cold vapour generation; In-line separation