QUANTITATIVE GAS-CHROMATOGRAPHIC ANALYSIS OF PLANT CUTICULAR WAXES CONTAINING LONG-CHAIN ALDEHYDES

The gas chromatographic quantification of long-chain aldehydes occurri ng in the cuticular waxes of numerous plant species is often non-repro ducible when silylating or methylating derivatization reagents are app lied. It is shown that, depending on reaction conditions, more than 50 % of the aldehydes present in a sample may be lost when total wax extr acts are analysed after silylation. A method involving the separation of the sample into two fractions by a simple solid phase extraction st ep has been developed. The fraction containing the long-chain aldehyde s can be analysed without derivatization. Extensive tests using analyt ical standards and authentic wax samples demonstrated that this method (applicable to sample sizes in the range from 0.2-0.5 mg of wax) allo ws for the quantitative and reproducible analysis of long-chain aldehy des. (C) 1998 John Wiley & Sons, Ltd.