Pesticide residue analysis in food with CGC — study of long-term stability by the use of different injection techniques

✍ Scribed by Müller, Hans-Martin ;Stan, Hans-Jürgen

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 392 KB
• Volume: 13
• Category: Article
• ISSN: 0935-6304
• DOI: 10.1002/jhrc.1240131009

✦ Synopsis

Abstract

An experiment was designed to study the long‐term stability of analyses of pesticide residues in a complex food matrix using three different injection techniques. A spinach sample was spiked with five sulfur‐containing pesticides of varying volatility and thermolability: azinphos‐ethyl, dimethoate, methiocarb, ethiofencarb, and tri‐allate. Tri‐allate was selected as internal standard because of its thermal stability and its good chromatographic properties. Flame photometric detection resulted in chromatograms not subject to interference by peaks of compounds of the matrix. Starting with a clean and freshly, silanized injector an additional deactivation was found to occur on the first injection of a food sample resulting in an increased peak area for all pesticides in relation to tri‐allate. Highest long‐term stability was found with PTV injection. Best results for thermolabile carbamates were obtained using on‐column injection. However, they were prone to faster deterioration.