Separation and preconcentration of cadmium ions using octadecyl silica membrane disks modified by methyltrioctylammonium chloride.
A simple and selective method for the determination of cadmium in water samples by FAAS after solid phase extraction has been developed. The method is based on the sorption of cadmium as CdI(4)(2-) on octadecyl silica membrane disks modified by cationic surfactant of methyltrioctylammonium chloride in the pH range of 1-8. The sorbed cadmium is then eluted with 10ml of 1moll(-1) nitric acid in ethanol and is measured by flame atomic absorption spectrometry. The influence of flow rates of eluent and sample solution, iodide concentration and amount of surfactant in retention and elution of cadmium from disks was also investigated. A preconcentration factor of 100 was achieved by passing 1000ml of sample through the membrane disk. The limit of detection (LOD) of cadmium was found to be 0.014ngml(-1). Precision at 2.5mugl(-1) was 1.2% (n=8). The method was successfully applied to the determination of cadmium in some natural water samples. The accuracy was assessed through recovery experiment, independent analysis by graphite furnace atomic absorption spectrometry, and analysis of certified reference waters.
Haji Shabani
Ali Mohammad
AM
Department of Chemistry, Yazd University, Yazd 89195-741, Iran.
Dadfarnia
Shayesteh
S
Motavaselian
Fatemeh
F
Ahmadi
Seyyed Hamid
SH
D002104:Cadmium / Q000737:chemistry* / Q000302:isolation & purification; D000431:Ethanol / Q000737:chemistry; D007202:Indicators and Reagents; D008567:Membranes, Artificial; D017942:Nitric Acid / Q000737:chemistry; D011193:Potassium Iodide / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D012997:Solvents; D013054:Spectrophotometry, Atomic
D007202:Indicators and Reagents; D008567:Membranes, Artificial; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D012997:Solvents; C026679:octadecylsilica; D002104:Cadmium; D011193:Potassium Iodide; D000431:Ethanol; D017942:Nitric Acid; C037759:trioctylmethylammonium; D012822:Silicon Dioxide