Use of a Novel Sol–Gel Dibenzo-18-Crown-6 Solid-Phase Microextraction Fiber and a New Derivatizing Reagent for Determination of Aliphatic Amines in Lake Water and Human Urine

Abstract

Dibenzo-18-crown-6 as a novel coating for solid phase microextraction (SPME) fibers has been prepared by sol–gel technology. The performance of the coating is stable at high temperature (350 °C) and the coating has a long lifetime (it can be used more than 150 times). The extraction properties of the new coating for derivatized aliphatic amines such as methylamine, dimethylamine, ethylamine, propylamine, butylamine, pentylamine, and hexylamine were investigated. Compared with commercial 100 μm PDMS and 85 μm PA fibers the sol–gel dibenzo-18-crown-6 coating is more sensitive and selective for derivatized aliphatic amines. A new derivatizing reagent, tetrafluorobenzoic acid N-hydroxysuccinimide ester (TFBza-suc) was synthesized for derivatization of aliphatic amines. In pH 8.3 H3BO3–Na2B4O7 buffer at 40 °C in a water bath the derivatization reaction is complete within 15 min and excess reagent need not be removed, which greatly simplifies sample preparation. The selectivity and sensitivity of this method for determination of aliphatic amines in lake water and urine can be significantly improved by coupling derivatization with SPME during sampling. The calibration plot was highly linear throughout the concentration range 0.1 to 1000 μg L−1. Method detection limits were below 0.05 μg L−1 for GC–FID. The reproducibility of the method was less than 6% RSD. Lake water and urine samples were analyzed.