Direct Immersion-Solid Phase Microextraction for the Determination of Chlorinated Pesticide Residues in Tomatoes by Gas Chromatography with an Electron Capture Detector

2013 ◽  
Vol 96 (6) ◽  
pp. 1430-1434 ◽  
Author(s):  
Maurizio Boccacci Mariani ◽  
Vanessa Giannetti ◽  
Elena Testani ◽  
Valentina Ceccarelli
Keyword(s):  
Electron Capture ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Correlation Coefficients ◽  
Electron Capture Detection ◽  
Extraction Temperature ◽  
Chlorinated Pesticides ◽  
Salting Out ◽  
Direct Immersion

Abstract The use of pesticides in agriculture has grown dramatically over the last decades. Environmental exposure of humans to agrochemicals is common and results in both acute and chronic health effects. In this study, direct immersion-solid phase microextraction (SPME) was coupled with electron capture detection for trace determination of 19 chlorinated pesticides in tomato samples, using a 100 μm polydimethylsiloxane fiber. The experimental parameters extraction time, extraction temperature, stirring, and salting out were evaluated and optimized. The LODs ranged from 0.5 to 8 μg/kg, and the LOQs from 5 to 30 μg/kg. A linear response was confirmed by correlation coefficients ranging from 0.97 to 0.9985. The developed method was tested by analyzing real samples purchased within the network of Italian distribution. The samples were found to be free from detectable residues of the studied pesticides. SPME has been shown to be a fast extraction technique that has several advantages such as solvent-free extraction, simplicity, and compatibility with the chromatographic analytical system.

Interferences of Surfactants During Determination of Chlorophenols by Acetylation Coupled to Headspace-Solid Phase Microextraction-Gas Chromatography with an Electron Capture Detector

2015 ◽  
Vol 98 (2) ◽  
pp. 524-528 ◽  
Author(s):  
Teodor Stoichev ◽  
Paulo de Morais ◽  
M Clara P Basto ◽  
M Teresa S D Vasconcelos
Keyword(s):  
Electron Capture ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Electron Capture Detector ◽  
Solid Samples ◽  
Salting Out ◽  
Micellar Extraction ◽  
Lauryl Ether ◽  
Method Optimization

Abstract The micellar extraction (ME) of chlorophenols (CPs) from solid samples is rapid and avoids the use of organic solvents. The cationic surfactant cetyltrimethylammonium bromide (CTAB) is a powerful agent for ME of CPs. However, CTAB will be an important interference when the extracts are subsequently analyzed by direct solid phase microextraction (SPME) without a previous derivatization step. Therefore, CTAB is usually replaced by the nonionic surfactant polyoxyethylene-10-lauryl ether (POLE), which causes less interference but is less efficient in extracting CPs. In order to assess to what extent the derivatization of CPs with headspace (HS) sampling would be able to reduce surfactant interferences, CPs were measured in the presence of CTAB or POLE using acetylation and HS-SPME coupled to GC with an electron capture detector. Experiments were carried out both in water and in a 0.1 g/mL solution of NaCl (salting out agent). Acetylation and HS-SPME strongly decreased the interference of CTAB for CP determination. Therefore, the application of CTAB followed by SPME determination for an efficient ME of CPs from solid samples should be reconsidered since using CTAB with HS-SPME after acetylation proved to be a potential tool for CP determination in those matrixes after method optimization.

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