DETERMINATION OF ALKYLPHENOLS IN RIVER WATER USING AN ETCHED STAINLESS STEEL WIRE - IONIC LIQUID - SOLID PHASE MICROEXTRACTION TECHNIQUE.

Alkylphenols (APs) are ubiquitous environmental endocrine-disrupting chemicals (EDCs) arising from the degradation of alkylphenol polyethoxylates (APnEOs) in water systems. Emerging research suggests that Aps are widely distributed in various environmental matrices, and an increased awareness of their presence has led to an intensified interest in the trace analyses of these compounds . In this study, an etched stainless steel wire - ionic liquid (IL) - solid phase microextraction (SPME) device was developed for the direct extraction of four APs from water samples, namely 4-n-pentylphenol (4-NPP), 4-n-hexylphenol (4-NHP), p-tert-octylphenol (P-TOP) and nonylphenol (NP). The experimental data demonstrated that the etched stainless steel wire was a suitable substrate for IL-SPME, maintaining its high mechanical strength and, at the same time, a significant adsorption power toward ILs. The coating was prepared by direct deposition of the ILs onto the surface of the etched stainless steel wire, which exhibited a porous structure and a high surface area. Among the others ILs, 1-butyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) exhibited maximum efficiency under the following experimental conditions: extraction time of 30 min, pH 2, sample temperature of 40 °C, and stirring. The IL coating exhibited an enrichment factor (EF) for the four APs, defined as the ratio between the concentration of the target compounds after and before the extraction, in the range 1382 – 4779. The detection limits (LOD, S/N = 3) ranged from 0.01 to 0.04 ng mL−1, and the RSD values for purified water spiked with APs ranged from 4.0 to 11.8% (n = 3). The calibration curves were linear in the range 0.5 - 200 ng mL−1 (R2 > 0.95). The optimized method was successfully applied for the analysis of real water samples.