Influence of extraction parameters and medium on efficiency of solid-phase microextraction sampling in analysis of aliphatic aldehydes

The main sorption conditions were optimized in the solid-phase microextraction (SPME) analysis of aldehydes that have different degrees of saturation. Aliphatic aldehydes were analyzed quantitatively in oil matrix and in aqueous solution by GC-MS using SPME sampling. The effectiveness of the immersion and the headspace techniques was compared in water. Samples were analyzed by gas chromatography with mass spectral detection using a medium polar CP WAX 52 CB column. The optimal exposure time was 30 min at 40 degrees C using a 100 mu m poly(dimethylsiloxane) coating. A ratio of liquid to headspace volume of 1:1 resulted in the best extraction in headspace analysis. Principal component analysis (PCA) was carried out to find similarities among various aldehydes and among conditions of optimization. The PCA identifies three clusters corresponding to analysis conditions (immersion in water, headspace above water and headspace above oil). The aldehydes behave similarly with the exception of dienals. (C) 1999 Elsevier Science B.V. All rights reserved.