Application of single-drop microextraction coupled with gas chromatography for the determination of multiclass pesticides in vegetables with nitrogen phosphorus and electron capture detection

Amvrazi, Elpiniki G.; Tsiropoulos, Nikolaos G.

doi:10.1016/j.chroma.2008.07.070

Cited by 64 publications

(37 citation statements)

References 37 publications

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“…Most of the pesticide determination in food samples is usually performed using GC in combination with electroncapture detection (ECD) [1,2], nitrogen-phosphorus detection [2,3] or MS detection [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Matrix effects observed during pesticides residue analysis in fruits by GC

Freitas¹,

Lanças²

2009

J of Separation Science

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The influence of the sample matrix in the GC-electron-capture detection analysis of the pesticides dimethoate, diazinon, chlorothalonil, parathion methyl and fenitrothion in fruits samples has been studied. Experiments have been carried out where the pesticide responses in standard solutions prepared in selected solvent were compared with their response when present in apple, mango, papaya, banana, pineapple and melon extracts. The presence of matrix effects (MEs) and their extent were shown to be simultaneously influenced by several factors (matrix concentration, matrix type, pesticide concentration, analytical range). Pronounced MEs were observed particularly for dimethoate and diazinon in all matrices tested; in lower concentrations, all pesticides presented significant ME. The other pesticides presented variable ME. Higher ME enhancement was detected at lower pesticide concentration levels of and/or at higher matrix concentration solutions. The ME detected for fenitrothion, in the analytical range evaluated, were dependent on matrix type. For each pesticide, solvent and matrix-matched calibrations were compared for all fruit samples, and it could be concluded that quantitation based on standard solutions prepared in blank matrix extract (matrix-matched calibration) should be used to compensate the MEs and to obtain more accurate results for the pesticides studied. IntroductionMost of the pesticide determination in food samples is usually performed using GC in combination with electroncapture detection (ECD) [1,2], nitrogen-phosphorus detection [2,3] or MS detection [4][5][6].Analytical procedures for determination of pesticides in fruit matrices are usually based on an extraction step, using conventional liquid-liquid extraction, followed by a clean-up procedure prior to chromatographic analysis [7,8]. Several methods based on supercritical fluid extraction [9, 10], solidphase extraction [11,12], solid-phase microextraction [13], stir bar sorptive extraction [14][15][16] and matrix solid-phase dispersion (MSPD) [1,5,[17][18][19][20][21][22][23] have been developed to overcome the drawbacks caused by using high amounts of glassware and toxic solvents in the classical liquid extraction methods.MSPD has proven useful as an extraction technique for the determination of pesticide residues in fruits and vegetables by GC [1,4] or LC [18,19]. The MSPD procedure allows the extraction and cleanup of analytes in a single step and is based on the dispersion of the sample on an adsorbent, such as florisil, C18, alumina or silica, followed by eluting with a small amount of solvent [24]. However, in spite of the fact that most of these modern methods provide a simple and rapid procedure for the determination of pesticides in fruits matrices, they do not avoid the presence of co-extracted matrix components that can result in a matrix effect (ME) in the pesticide analysis [25][26][27].MEs are notoriously variable in occurrence and intensity, the GC technique being particularly prone to them [5,28]. The ME is a phenomenon th...

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Section: Introductionmentioning

confidence: 99%

Matrix effects observed during pesticides residue analysis in fruits by GC

Freitas¹,

Lanças²

2009

J of Separation Science

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“…It has been well documented that the extraction of analytes from sample solution to organic liquid drop could be influenced by several conditions [4,24]. Therefore, parameters such as selection of organic solvent, sample agitation rate, extraction time, microdrop volume and ionic strength were optimized for the SDME process.…”

Section: Parameters Optimization For Sdme Techniquementioning

confidence: 99%

“…Ahmadi et al employed some modification of the needle tip, causing its cross section to increase and increasing adhesion force between the needle tip and the drop, thereby increasing drop stability and achieving a higher stirrer speed (up to 1,700 rpm) [30]. SDME in pesticide residues analysis has been applied with success in both liquid water [27,30,31], juices [32,33], wine [34,35], oils [36] and solid samples (vegetables [24,37,38], fish [39] by providing low limits of detection and high selectivity as compared with classic robust sample preparation techniques. The novel approachs of SDME were developed by different authors.…”

Section: Introductionmentioning

confidence: 99%

“…In the determination of OCP in different samples, many preparative processes such as liquid-liquid extraction (LLE) [8], microwave assistant extraction (MAE) [9][10][11], supercritical fluid extraction (SFE) [8,12], solid-phase extraction (SPE) [13][14][15] and solid-phase microextraction (SPME) [16][17][18][19] have been suggested. Other sophisticated methods for sample preparation such as matrix solid-phase dispersion (MSPD) [20,21] and QuEChERS method (acronym for quick, easy, cheap, effective, rugged and safe) [22,23] have also been developed by providing favorable recoveries and also simultaneously lower cost and time of analysis [24].…”

Section: Introductionmentioning

confidence: 99%

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The development and optimization of a modified single-drop microextraction method for organochlorine pesticides determination by gas chromatography-tandem mass spectrometry

et al. 2012

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We have developed a new method for single-drop microextraction (SDME) for the preconcentration of organochlorine pesticides (OCP) from complex matrices. It is based on the use of a silicone ring at the tip of the syringe. A 5 μL drop of n-hexane is applied to an aqueous extract containing the OCP and found to be adequate to preconcentrate the OCPs prior to analysis by GC in combination with tandem mass spectrometry. Fourteen OCP were determined using this technique in combination with programmable temperature vaporization. It is shown to have many advantages over traditional split/splitless injection. The effects of kind of organic solvent, exposure time, agitation and organic drop volume were optimized. Relative recoveries range from 59 to 117 %, with repeatabilities of <15 % (coefficient of variation) were achieved. The limits of detection range from 0.002 to 0.150 μg kg −1 . The method was applied to the preconcentration of OCPs in fresh strawberry, strawberry jam, and soil.

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“…An effective extraction was achieved by suspending a 1.0 µL mixed drop of p-xylene and acetone (8:2 w/v) to the tip of a microsyringe immersed in a 2 mL donor sample solution and stirred at 400 rpm (Zhang et al, 2008). SDME technique coupled with GC-NPD and GC-ECD has also been successfully applied for the determination of multiclass pesticides in vegetable samples (tomato and courgette) by Amvrazi & Tsiropoulos (2009). Donor sample solution preparation from solid vegetable tissues was achieved in one step with the minimum amount of organic solvent (10% acetone in water) and optimum SDME was accomplished using a toluene drop (1.6 µL) under mild stirring for 25 min.…”

Section: Fig 1 Schematic Illustration Of Direct Immersion Single-drmentioning

confidence: 99%

Current Trends in Liquid-Liquid Microextraction for Analysis of Pesticide Residues in Food and Water

Cunha¹,

Fernandes²,

Oliveira³

2011

Pesticides - Strategies for Pesticides Analysis

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Application of single-drop microextraction coupled with gas chromatography for the determination of multiclass pesticides in vegetables with nitrogen phosphorus and electron capture detection

Cited by 64 publications

References 37 publications

Matrix effects observed during pesticides residue analysis in fruits by GC

Matrix effects observed during pesticides residue analysis in fruits by GC

The development and optimization of a modified single-drop microextraction method for organochlorine pesticides determination by gas chromatography-tandem mass spectrometry

Current Trends in Liquid-Liquid Microextraction for Analysis of Pesticide Residues in Food and Water

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