Application of Cold-Induced Aggregation Microextraction Based on Ionic Liquid for Determination of Trace Amount of Cadmium and Lead in Powder Milk Samples

Abstract

Background: cold-induced aggregation micro extraction based (CIAME) based on ionic liquid was used as a rapid and simple method for determination trace amounts of cadmium and lead in milk powder by analysis with flame atomic absorption spectrometry (FAAS). Methods: Sample solution containing of Cd2+ and Pb2+ in dynamic range, phosphate buffer (pH = 9, 3 ml), diethyl dithiocarbamate (complexing agent), Triton X-100, NaPF6 ,[HMIM][PF6] (extraction solvent) were transferred into conical bottom glass tube. Sample was kept in a thermostated bath and then ice bath; a cloudy solution was formed. Two phases separated by centrifugation. After removing of aqueous phase, IL-phase was dissolved in methanol and diluted was injected to the FAAS by microsampler introduction. Results: ILs, containing imidazoliumcation and hexafluoro phosphate anion, [HMIM][PF6](70mg), 200 mg NaPF6 ,0.01 mol.L-1 DDTC, 0.015% of Triton X-100 obtained, pH 9 and centrifuge time; 5 min (4000 rmp) was chosen. Detection limit were obtained 0.12 µgL-1, 1.61µgL-1, RSD 0.95%, 2.2% and enrichment factor of 70, 67 for Cd and Pb, respectively. Conclusion: CIAME allows determination of cadmium and lead in real samples in a simple, rapid and safe method with only a small amount of ionic liquid was used. In comparison with the organic solvent extraction, CIAME is much safer and the determination of species in high ionic strength samples is possible.

Keywords

• Cadmium
• CIAME
• IL
• Lead.