Application of Solid Phase Micro‐Extraction (SPME) to the analysis of pesticide residues in vegetables

Abstract

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

Application of solid-phase microextraction for determining phenylurea herbicides and their homologous anilines from vegetables

“…A dilution of 1/5 was sufficient to reduce matrix interference and to reach enough sensitivity. Dilution was also chosen by other authors who extracted aqueous matrices with suspended matter such as fruits [17,18], vegetable [22] and honey [19,21].…”

“…Although the fiber cannot be submerged in a solid, some applications of SPME to analyze pesticide residues in solid matrices have been reported. The problem of the solid state of the sample has been resolved by using headspace (HS)-SPME [15,16] or by obtaining an aqueous extract from the sample [17][18][19][20][21][22][23][24][25]. Direct SPME has been applied to determine pesticide residues in liquid foods as wine [11,[26][27][28] and juice fruit [16,18,27] and, HS-SPME has been used in wines [29,30].…”

“…Direct SPME has been applied to determine pesticide residues in liquid foods as wine [11,[26][27][28] and juice fruit [16,18,27] and, HS-SPME has been used in wines [29,30]. It has been reported that complex matrices such as soil [31], vegetables [22], fruits [17,18] and honey [19,21] can cause interferences in SPME. The use of deuterated surrogates or internal standard calibration may correct such matrix effects.…”

Application of solid-phase microextraction for the determination of pyrethroid residues in vegetable samples by GC-MS

“…Although several papers deal with direct immersion of the SPME fiber into a slurry of fruit with water [21,29], other authors describe the need for a previous extraction of pesticides and the subsequent application of DI-SPME over the separated aqueous extract [30,31,32,33]. The use of microwave-assisted extraction allows one to increase the extraction efficiency of less polar pesticides using water as extractant [29,34].…”

Development of polymethylphenylsiloxane-coated fiber for solid-phase microextraction and its analytical application of qualitative and semi-quantitative of organochlorine and pyrethroid pesticides in vegetables

“…Solid-phase microextraction (SPME) which combines simultaneous extraction and preconcentration of analytes from different matrices into one step was developed by Pawliszyn and co-workers [15]. In the last several years, extensive application of SPME in the extraction of pesticide residues of vegetables has been reported [16][17][18][19][20][21]. However, all of the work mentioned above employed commercial fibers and, although commercial fibers are easy to manipulate and provide good analytical precision, they still have some drawbacks including lower extraction efficiency, nonresistance to high temperature and organic solvents, high cost and short-life usability.…”