Use of a novel sol-gel dibenxo-18-crown-6 solid-phase microextraction fiber and a new derivatizing reagent for determination of aliphatic amines in lake water and human urine

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 degreesC) 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 mum PDMS and 85 mum 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 degreesC 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 mug L-1. Method detection limits were below 0.05 mug L-1 for GC-FID. The reproducibility of the method was less than 6% RSD. Lake water and urine samples were analyzed.