RESUMEN
The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7-84 µg L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 µg L-1, 1.7 µg L-1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g-1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.