On-line ionic liquid-based preconcentration system coupled to flame atomic absorption spectrometry for trace cadmium determination in plastic food packaging materials

ESTEFANÍA M. MARTINISA,B, ROBERTO A. OLSINAB,D, JORGELINA C. ALTAMIRANOA,B,C, RODOLFO G.WUILLO

TALANTA

ELSEVIER SCIENCE BV

Año: 2009 vol. 78 p. 857 - 862

0039-9140

A novel on-line preconcentration method based on liquid–liquid (L–L) extraction with room temperatureionic liquids (RTILs) coupled to flame atomic absorption spectrometry (FAAS)was developed for cadmiumdetermination in plastic food packaging materials. The methodology is based on the complexation of Cdwith 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) reagent after sample digestion followedby extraction of the complex with the RTIL 1-butyl-3-methylimidazolium hexafluorophosphate([C4mim][PF6]). The mixture was loaded into a flow injection analysis (FIA) manifold and the RTIL richphasewas retained in a microcolumn filled with silica gel. The RTIL rich-phase was then eluted directlyinto FAAS. A enhancement factor of 35 was achieved with 20mL of sample. The limit of detection (LOD),obtained as IUPAC recommendation,was 6 ng g−1 and the relative standard deviation (R.S.D.) for 10 replicatesat 10gL−1 Cd concentration level was 3.9%, calculated at the peak heights. The calibration graphwas linear and a correlation coefficient of 0.9998was achieved. The accuracy of themethodwas evaluatedby both a recovery study and comparison of results with direct determination by electrothermal atomicabsorption spectrometry (ETAAS). The method was successfully applied for Cd determination in plasticfood packaging materials and Cd concentrations found were in the range of 0.04–10.4gg−1.© 2009 Elsevier B.V. All