Hollow fiber liquid-phase microextraction of cadmium(II) using an ionic liquid as the extractant

A method is presented for hollow fiber liquid-phase microextraction (HF-LPME) of cadmium(II), which is chelated with 1-(2-pyridylazo)-2-naphthol (PAN) to obtain a hydrophobic complex which then is extracted into a polypropylene hollow fiber containing an ionic liquid in its pores which acts as the membrane phase. EDTA is then injected into the lumen of the membrane as an acceptor phase to trap the analyte. The extraction time (20 min), agitation (400 rpm at 25 A degrees C), pH value (10.0), and the concentrations of PAN (2.5 ng mL(-1)) and EDTA (250 ng mL(-1)) were optimized. With a sample volume of 50 mL and a stripping volume of 15 mu L, the enrichment factor is 162. Cadmium(II) was then quantified by graphite furnace AAS. The limit of detection is 0.12 pg mL(-1), the relative standard deviation is 5.2 %, and the linear working range extends from 4 to 45 pg mL(-1). The method was successfully applied to the determination of Cd(II) in environmental and food samples.