Analysis Of Pesticide Residues In Food Research Articles

Residue analysis of onions and other foodstuffs with a complex matrix using two-dimensional capillary-GC with three selective detectors

Pesticide residue analysis in food is mainly performed by multimethods. In Germany, multimethod S 19 of the DFG pesticide commission is in widespread use. Applying this method to onion and leek samples, GC-ECD analysis becomes very difficult as most of the pesticide peaks are overlapped by matrix compounds. Two-dimensional capillary-GC using the techniques of heart-cutting and backflush makes it possible to transfer small fractions or even single peaks to a second column where all relevant pesticides can be separated from their overlapping matrix compounds. Nitrogen and phosphorus containing pesticides in onion and leek samples are identified by selective detectors (NPD, FPD) without any problem.

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

AbstractAn 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.

Capa — computer aided pesticide analysis : Computer program for the automated evaluation of chromatographic data for residue analysis of foods

Pesticide residue analysis in food by means of gas chromatography with columns of different polarity and several selective detectors provides the analyst with a great number of chromatographic data. The introduction of personal computer based chromatographic data systems into research laboratories increased the efficiency of information management and organization; user designed software packages now have direct access to the stored data. The computer program CAPA (Computer Aided Pesticide Analysis) was developed for the interpretation and evaluation of chromatographic results. The program is written in TURBO PASCAL 3.0 and consists of everal subprograms. In the main database all pesticides are filed in a multidimensional structure. The various subprograms have access to this catalog of retention and response data. Using the subprogram INTERPRET, which is the core of CAPA, the analyst is provided with all information necessary to interpret a gas chromatogram: identification of calibrated pesticides and estimation of their concentration. Automated screening analyses can be evaluated with the subprogram AUTOINTERPRET, an automated version of interpret that uses all relevant information stored in the data base. A report is produced containing the pesticides found in the sample and proposals how to confirm them best with the equipment and methods available. Finally the analyst has to make the decision about the probable presence and quantity of the indicated pesticides and to project the next confirmatory step by using INTERPRET.