Determination of Aliphatic Amines in Air by On-Line Solid-Phase Derivatization with HPLC-UV/FL

Abstract

An easy, rapid, and efficient method using on-line solid-phase derivatization in HPLC is developed for the trace determination of aliphatic amines in air. Some fundamental studies on stop-flow, on-line, solid-phase derivatizations in HPLC are also investigated, such as optimization of the reaction detection HPLC system and band broadening. Air is sampled with silica gel tubes from different sites, including sewage areas, fish cleaning and processing rooms, and an organoleptic lab of the U.S. Food & Drug Administration (FDA). The trapped amines are desorbed with an acidic aqueous-organic solution, followed by pH adjustment of the eluates to pH 10. The resulting solution is directly injected into an on-line, precolumn, solid-phase derivatization and reversed-phase HPLC-UV/FL system, not requiring any further sample workup steps. The percent derivatizations are as high as 88 +/- 5% (n = 3) for primary amines, and 75 +/- 4% (n = 3) for diethylamine under optimized conditions (60 degrees C for 10 min). The recoveries for all amines are above 90%. The method is validated by a single-blind, spiked experiment with 1.1-4.4% relative standard deviation (RSD) in the range of 15-47 ppm. These results are confirmed by a GC-FID method performed in another lab. Amines are quantitated via calibration plots, with final concentrations from 0.02 to 0.38 mg/m3 air. It is suggested that this newer approach for the determination of amines and polyamines, using polymeric solid-phase reagents on-line, precolumn in HPLC, should prove generally successful for other amines and other sample types in the future.