Abstract—Applied all over the world, pesticides are some of the most common pollutants of the environment because of their stability, mobility, their consequent long-term adverse effects on living organisms in general and human health in particular. For these reasons it is essential to monitor and analyse pesticide residues in the fruits and vegetables. The analysis of food samples for the presence of pesticides causes a lot of difficulties in consideration of specificity of sample preparation based on multistage operations of purification of sample containing vestigial amount of analyte with simultaneous large amount of interferents. The extraction and determination of pesticide residues in fruit and vegetable samples are discussed, as are the techniques most commonly used in these processes. The difficulties occurring at each stage in the analytical procedure are outlined. Index Terms—Fruits, pesticides, sample preparation, vegetables. I. INTRODUCTION Main source of pesticide residues in vegetable products is their direct application in the crops to eliminate different types of pest. Due to the low detection levels required by regulatory bodies and the complex nature of the matrices in which the target compounds are present, efficient sample preparation and trace-level detection and identification are important aspects in an analytical method. Multiresidue method development is difficult, due to the fact that compounds of different polarities, solubilities, volatilities and pKa values have to be simultaneously extracted and analysed. Fruit and vegetables are capable of retaining larger quantities of pesticides. Pesticides can accumulate in fruit skins. The crops most exposed to the presence of pesticides are grapes, citrus fruits and potatoes. Adsorbed pesticides can reduce the nutritious value of crops or alter their organoleptic properties. The present-day trend is to move away from persistent pesticides and to apply agents with a short decomposition time. Organochlorine pesticides have been replaced by organonitrogen and – phosphorus pesticides. Currently 520 approved active ingredients are used in nearly 2000 commercial products. These substances belong to more than 100 different classes. It is estimated that EU countries consume more than 300,000 tons of pesticides per annum for Manuscript received March 13, 2014; revised May 25, 2014. This work was supported in part by a grant (No. 2012/05/N/ST4/02019) from the Ministry of Science and Higher Education, Poland. The authors are with the Department of Analytical Chemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza Str. 11/12, 80-233 Gdansk, Poland (e-mail: [email protected]). crop protection alone [1]. II. TECHNIQUES FOR ISOLATING PESTICIDES FROM FRUIT AND VEGETABLE SAMPLES Isolation and/or enrichment involve the transfer of analytes from the primary matrix to a secondary one with the concomitant removal of interferents and the increase of analyte concentrations to levels above the limit of determination (LOD) of the analytical technique used [2], [3]. The usual techniques for isolating pesticides from fruit and vegetable samples are: liquid-liquid extraction (LLE), pressurized liquid extraction (PLE), liquid-liquid microextraction (LLME), microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE). Extract clean-up techniques are the most commonly employed solid-phase extraction (SPE), solid-phase microextraction (SPME), stir bar solvent extraction (SBSE) and gel permeation chromatography (GPC) [4]-[10]. Solid phase extraction (SPE) is currently the most popular extract clean-up technique [11]. Many of the published methods for pesticide determination in fresh fruits and vegetables use a combination of two or more commercially available SPE columns for clean-up in the normal-phase (NP) mode. Weak anionexchange sorbents such as primary secondary amine (PSA), aminopropyl (NH2), or diethylaminopropyl (DEA) modified silica are often used for clean-up of food samples together with strong anion-exchange sorbents (SAX, QMA). Other SPE clean-up approaches include the combination of GCB (graphitised carbon black) and PSA columns, the combination of C18, GCB and aminopropyl and the combination of GCB, PSA and SAX columns. A modification of SPE is dispersive solid phase extraction (dSPE). Dispersive-SPE involves the mixing of the sorbent with the extract in a mini-centrifuge tube to retain matrix interferents, but not analytes [12]. A modification of SPE, i.e. solid phase microextraction (SPME) [13], involves the adsorption of analytes on a fiber coated with a suitable solid phase that can be pushed out of a microsyringe. The analyte is then thermally desorbed and transferred to the GC injector. Depending on where the fibre is placed in relation to the sample, SPME can be divided into: direct (Direct Immersion DI - SPME) or headspace (HS-SPME). The method is not suitable for weakly volatile or thermally labile compounds as most pesticides are [14]. III. QUECHERS TECHNIQUE Approaches are being sought to develop pesticide Multiresidue Methods for Determination of Currently Used Pesticides in Fruits and Vegetables Using QuEChERS Technique Marek Biziuk and Jolanta Stocka 18 DOI: 10.7763/IJESD.2015.V6.554 International Journal of Environmental Science and Development, Vol. 6, No. 1, January 2015
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Abstract—Applied all over the world, pesticides are some of
the most common pollutants of the environment because of
their stability, mobility, their consequent long-term adverse
effects on living organisms in general and human health in
particular. For these reasons it is essential to monitor and
analyse pesticide residues in the fruits and vegetables. The
analysis of food samples for the presence of pesticides causes a
lot of difficulties in consideration of specificity of sample
preparation based on multistage operations of purification of
sample containing vestigial amount of analyte with
simultaneous large amount of interferents. The extraction and
determination of pesticide residues in fruit and vegetable
samples are discussed, as are the techniques most commonly
used in these processes. The difficulties occurring at each stage
in the analytical procedure are outlined.
Index Terms—Fruits, pesticides, sample preparation,
vegetables.
I. INTRODUCTION
Main source of pesticide residues in vegetable products is
their direct application in the crops to eliminate different
types of pest. Due to the low detection levels required by
regulatory bodies and the complex nature of the matrices in
which the target compounds are present, efficient sample
preparation and trace-level detection and identification are
important aspects in an analytical method. Multiresidue
method development is difficult, due to the fact that
compounds of different polarities, solubilities, volatilities
and pKa values have to be simultaneously extracted and
analysed. Fruit and vegetables are capable of retaining larger
quantities of pesticides. Pesticides can accumulate in fruit
skins. The crops most exposed to the presence of pesticides
are grapes, citrus fruits and potatoes. Adsorbed pesticides can
reduce the nutritious value of crops or alter their organoleptic
properties. The present-day trend is to move away from
persistent pesticides and to apply agents with a short
decomposition time. Organochlorine pesticides have been
replaced by organonitrogen and – phosphorus pesticides.
Currently 520 approved active ingredients are used in nearly
2000 commercial products. These substances belong to more
than 100 different classes. It is estimated that EU countries
consume more than 300,000 tons of pesticides per annum for
Manuscript received March 13, 2014; revised May 25, 2014. This work
was supported in part by a grant (No. 2012/05/N/ST4/02019) from the
Ministry of Science and Higher Education, Poland.
The authors are with the Department of Analytical Chemistry, Faculty of
Chemistry, Gdansk University of Technology, Narutowicza Str. 11/12,