Efficient solid-phase microextraction of triazole pesticides from natural water samples using a Nafion-loaded trimethylsilane-modified mesoporous silica coating of type SBA-15

Abstract

A mesoporous silica surface of type SBA-15 was made more hydrophobic by modification with ethoxytrimethylsilane to obtain a hybrid organic–inorganic mesoporous nanocomposite, which then was impregnated with Nafion. The resulting nanocomposite was used as a fiber coating for solid-phase microextraction (SPME). The trimethylsilyl-modified Nafion/SBA-15 nanocomposite with high surface area was characterized by SEM and FTIR. It was immobilized on a stainless steel wire in order to fabricate a fiber for SPME. This fiber was evaluated for its suitability for extracting triazolic agrochemicals from water samples before their quantification through a combination of gas chromatography and mass spectrometry. Experimental conditions for fiber coating, extraction time, stirring rate, ionic strength, pH value, desorption temperature and desorption time were optimized. Under optimum conditions, the repeatability for one fiber (for n = 3) ranges from 4.3 to 5.6 % (relative standard deviation). The detection limits are between 50 and 90 pg⋅mL−1. The method is simple, fast, low-cost (in terms of equipment), and the fiber used for SPME has high thermal stability and good recovery.