Functionalized nanometer-sized alumina supported micro-solid phase extraction coupled to inductively coupled plasma mass spectrometry for preconcentration and determination of trace metal ions in gasoline samples

Nanometer-sized alumina functionalized with [3-(2-aminoethylamino) propyl] trimethoxysilane (nano-Al2O3/AAPTMS) was prepared as an adsorbent for preconcentration of trace element ions in gasoline samples. The nano-Al2O3 was characterized by XRD, SEM and BET techniques and the functionalized adsorbent was characterized by ATR-FTIR spectroscopy. The nano-Al2O3/AAPTMS sorbent was used as the packing material in the supported micro-solid-phase extraction (mu-SPE) device. The latter was coupled with inductively coupled plasma mass spectrometry (ICP-MS) for preconcentration and determination of trace elements in gasoline samples. The optimization of the preconcentration system was achieved by a multivariate strategy. Under optimized conditions, limits of detection (LOD) and quantification (LOQ) ranged from 0.2-0.7 ng L-1 to 0.7-2.3 ng L-1, respectively, and a preconcentration factor of 40 was achieved. The validity of the developed mu-SPE-ICP-MS procedure was confirmed by analysis of spiked gasoline samples. The supported mu-SPE-ICP-MS method was applied for quantification of Co, Cr, Mn, Ni and Ti in commercial gasoline samples. The mu SPE device coupled with ICP-MS provided improved LOD and LOQ for trace metal analysis in a gasoline matrix and significantly reduced matrix interference.