No abstract

The Solid Phase Micro-Extraction (SPME) technique was applied to analyze chlorpropham in potatoes and amitraz in honey. The homogenized sample, suspended in water and stirred, was extracted with a 100 microns thick polidimetylsiloxane fiber and desorbed into the injection port of a gas chromatograph/mass-spectrometer (quadrupole) operating in single ion monitoring. Sensitivities down to 0.01 mg/Kg and linear responses in the range of 0.01-0.1 mg/Kg were obtained. The results of SPME pesticide residue analysis in potatoes corresponded to those obtained with a traditional multiresidue method.

Results are presented that were obtained independently by two laboratories employing solidphase micro extraction (SPME) for the analysis of pesticide residues in honey. The compounds Amitraz, Coumaphos, Cymiazole, Bromopropylate and Fluvahnate, used for chemitherapic treatment of beehives and otherwidely used agricultural insecticides, were extracted using a polydimethylsiloxane fiber of 100 I~m thickness. The precision, accuracy, intervals of hnearity and detection limits of the method are discussed. Considering the rapidity and simplicity of this technique and, on the other hand, the difficulties arising from its application to a very complex matrix, SPME can certainly be considered a useful tool for the rapid screening of residues in honey.

Solid Phase Micro-Extraction (SPME) is a new analytical technique, based on capturing the analytes by adsorption onto an organic phase coating a glass ®bre, and subsequent direct desorption into the injector of a gas chromatograph. This technique has been successfully applied in the analysis of organic contaminants in water, giving linear responses and, in some cases, high sensitivities.The present paper reports data about the application of SPME to the analysis of pesticide residues in a vegetable matrix, testing over nearly one hundred active compounds, with two types of adsorbent phase (polydimethylsiloxane and Carbowax/divinylbenzene). A vegetable matrix spiked with pesticides was analyzed by SPME and by a traditional multi-residue method; recoveries were determined and compared for the two cases. The behaviour of the analytical response by SPME was studied in the range 0.01±1 mg kg À1 by adding increasing amounts of given pesticide mixtures to the vegetable matrix.The procedure was further tested by analyzing real samples, and gave some dif®culties in recovering the whole amount of some of the residues present (in comparison with the traditional method). The SPME method was then improved by pre-extracting with acetone and sonicating before the extraction/ adsorption step. The results obtained were satisfactory (some certi®ed matrices were also tested) with good accordance between the two methods. Nevertheless some active compounds showed very low responses or remained undetectable by SPME in our experimental conditions. a Added at a concentration two times higher then standard. b Added later. c Used for quantifying compound in SIM-GC/MS analysis. d Added at a concentration four times higher than standard. 620Pest Manag Sci 56:618±636 (2000) M Volante et al

Solid Phase Micro-Extraction (SPME) is a new analytical technique, based on capturing the analytes by adsorption onto an organic phase coating a glass ®bre, and subsequent direct desorption into the injector of a gas chromatograph. This technique has been successfully applied in the analysis of organic contaminants in water, giving linear responses and, in some cases, high sensitivities.The present paper reports data about the application of SPME to the analysis of pesticide residues in a vegetable matrix, testing over nearly one hundred active compounds, with two types of adsorbent phase (polydimethylsiloxane and Carbowax/divinylbenzene). A vegetable matrix spiked with pesticides was analyzed by SPME and by a traditional multi-residue method; recoveries were determined and compared for the two cases. The behaviour of the analytical response by SPME was studied in the range 0.01±1 mg kg À1 by adding increasing amounts of given pesticide mixtures to the vegetable matrix.The procedure was further tested by analyzing real samples, and gave some dif®culties in recovering the whole amount of some of the residues present (in comparison with the traditional method). The SPME method was then improved by pre-extracting with acetone and sonicating before the extraction/ adsorption step. The results obtained were satisfactory (some certi®ed matrices were also tested) with good accordance between the two methods. Nevertheless some active compounds showed very low responses or remained undetectable by SPME in our experimental conditions.