A New Ultrasound Assisted-Cloud Point Extraction Method for the Determination of Trace Levels of Tin and Antimony in Food and Beverages by Flame Atomic Absorption Spectrometry

摘要

In the current study, a new ultrasonic-assisted cloud-point extraction (UA-CPE) method for the preconcentration and determination of antimony and tin in the selected food and beverages was developed by flame atomic absorption spectrometry (FAAS). The method is based on the fact that formation of the stable ternary complexes of Sb(III) and Sn(IV) with 2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one (morin) in presence of cetyltrimethylammoniumbromide (CTAB) as both sensitivity improvement auxiliary ligand and counter ion, and then extraction into the micellar phase of poly(ethylene glycol-mono-p-nonylphenylether (PONPE 7.5) as extracting agent at pH 8.5. Under the optimized conditions, the calibration curves for Sb(III) and Sn(IV) were rectilinear with changing calibration sensitivities in ranges of 0.1-140 and 0.1-225 mu g L-1, respectively. The limit of detection for both Sb(III) and Sn(IV) was 0.03 mu g L-1 with sensitivity enhancement factor of 114.5 and 110.6, respectively. The precision as a relative standard deviation (RSD) for Sb(III) and Sn(IV) is in range of 2.3-5.2 and 2.6-5.4 %, respectively. The trueness of the method was verified by analysis of certified reference materials (CRMs). The method was successfully applied to determination of antimony and tin in the selected food and beverage matrices.