High thermal-stable sol-gel-coated calix[4]arene fiber for solid-phase microextraction of chlorophenols

A simple and rapid solid-phase microextraction (SPME) method using a 5,11,17,23-tetra-tert-butyl-25,27-diethoxy-26,28-dihydroxycalix[4] arene (C[4])/hydroxy-terminated silicone oil (OH-TSO) sol-gel-coated novel fiber was presented for direct analysis of four chlorophenols (2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol). Extraction parameters, such as extraction temperature, time, and pH were optimized. The thermal stability and carry-over with this new fiber was investigated in detail and results revealed that the development of C[4]/OH-TSO fiber can improve the carry-over of chlorophenols. The linear range for each chlorophenol was three or four orders of magnitude. The detection limits (S/N = 3) ranged from 0.005 to 0.276 mug/l and the relative standard deviation (n = 6) values were from 0.72 to 6.80%. The complete analytical procedure was applied to analyze river water and soil samples after ultrasonic extraction. The recoveries of those compounds studied in river water were 94.7, 97.4, 97.0 and 86.3% and it was 98.6, 97.0, 90.2 and 81.0% for the soil sample, respectively. (C) 2003 Elsevier B.V. All rights reserved.