Solid-phase microextraction in pesticide residue analysis

Pesticides in the Modern World - Trends in Pesticides Analysis, 2011

Sample preparation is applicable to all sample matrices; for example biotechnological, biological, environmental, forensic and pharmaceutical as it presents tremendous benefits. The reduction of interferences helps to prevent an overload on separation columns and subsequently extends the durability of analytical columns. Selective extraction improves the detection sensitivity levels of analytes of interest and simplifies the subsequent interpretation of chromatograms and other analytical data (Fontanals et al., 2007). Automation of the extraction process results in faster analysis and hence reduced overall cost of analysis (Smith, 2003). Traditional sample preparation techniques such as liquid-liquid extraction (LLE) and soxhlet extraction generated large volumes of solvent, were laborious, had low sample throughput and lacked selectivity (Baltussen et al., 1997; Moreno et al., 2007; Shimelis et al., 2007). Modern sample preparation techniques such as solid phase extraction (SPE) with its various commercially available sorbents and solid phase microextraction (SPME) have been driven by the move towards the consumption of micro-volumes of solvent to techniques that offer solventless extractions, automation, sample throughput, enrichment factor and selectivity (Wells and Lloyd, 2002; Hyötyläinen and Riekkola, 2008). These extraction approaches are usually easy to carry out and call for optimization of several parameters to enhance the performance of the overall analysis. The key to rational choice of a sample preparation technique for a particular matrix is based on an understanding of the fundamental principles governing the kinetics of mass transfer within the extraction system (Pawliszyn, 2003). This chapter briefly describes the fundamental principles of some of the modern sample preparation techniques employed to liquid and solid matrices for pesticide analysis. Parameters to be considered with each technique such as sample matrix type i.e. liquid or solid and the physicochemical properties of the analyte(s) of interest are discussed. Optimisation parameters for each technique are also discussed. 2. Liquid phase microextraction (LPME) This technique is a miniaturization of the traditional LLE and employs micro-volumes of solvent instead of the traditional tens or hundreds of milliliters (Mahugo-Santana et al., 2011). LPME is a two-phase system whereby analytes are transferred from an aqueous

Headspace solid phase microextraction (HS-SPME) was optimized for the analysis of pesticides with gas chromatography electron capture detection (GC-ECD) and high-resolution mass spectrometry. Factors influencing the extraction efficiency such as fiber type, extraction mode and temperature, effect of ionic strength, stirring and extraction time were evaluated. The lowest pesticide concentrations that could be detected in spiked aliquots after HS-SPME-GC-ECD ranged from 0.0005 to 0.0032 μg L − 1 . Consequently hexachlorobenzene, trans-chlordane, 4,4′-DDD and 4,4′-DDE were detected in water samples after HS-SPME at concentrations ranging from 2.4 to 61.4 μg L − 1 that are much higher than the 0.1 μg L − 1 maximum limit of individual organochlorine pesticides in drinking water set by the European Community Directive. The same samples were cleaned with ISOLUTE C 18 SPE sorbent with an optimal acetone/n-hexane (1:1 v/v) mixture for the elution of analytes. No pesticides were detected after SPE clean-up and pre-concentration. Precision for both methods was satisfactory with relative standard deviations less than 20%. This work demonstrated the superiority of HS-SPME as a sample clean-up and pre-concentration technique for pesticides in water samples as well as the need to identify and control point sources of pesticides.

Asian Pacific Journal of Cancer Biology, 2016

Introduction: Fungicides are a group of pesticides which are widely used and have negative effects on human health and the environment; Pesticide residues resulted from applying fungicides is a very important issue due to environmental pollution and human health risk and should be seriously considered. In order to achieve such insight summing up the dangers of pesticides is necessary so that attributes to predict social costs and benefits and monitor new policies applied.Methods: In this study, the possibility of extracting Triazole, a fungicide was evaluated by utilizing nanostructures, PW/SiO2, using new synthetic microextraction methods. Triazole is one of the most important pesticides with worldwide use for the protection of a variety of vegetables, fruits and grains and the destruction of many fungal pathogens because of its broad-spectrum and systemic properties.Results: In this study, a new synthetic microextraction is used in which the PW/SiO2 with nano-holes is applied for ...

Journal of biochemical and biophysical …, 2007

Modern trends in analytical chemistry are towards the simplification and miniaturization of sample preparation, as well as the minimization of organic solvent used. In view of this aspect, several novel micro-extraction techniques are being developed in order to reduce the analysis step, increase the sample throughput and to improve the quality and the sensitivity of analytical methods. One of the emerging techniques in this area is liquid-phase micro-extraction (LPME). It is a miniaturized implementation of conventional liquid/liquid extraction (LLE) in which only microliters of solvents are used instead of several hundred milliliters in LLE. It is quick, inexpensive and can be automated. In the last few years, LPME has been combined with liquid chromatography (LC) and capillary electrophoresis (CE), besides the generally used coupling to gas chromatography (GC), and has been applied to various matrices, including biological, environmental, and food samples. This work is aimed at providing an overview of the major developments of LPME, coupled with chromatography and CE, as reported in the literature. The paper will focus on the application of the technique to different matrices and the aim is to reveal the panorama of opportunities and to try to indicate the potential of LPME in pesticide analysis. A critical review of the first applications to pesticide analyses is presented in the main part of the manuscript. The optimization of LPME as well as advantages and disadvantages are discussed. It is concluded that, because of its high preconcentration factor, LPME can be introduced with benefit into water analysis for several pesticide groups. In particular, the application of LPME to non-polar pesticides in environmental analysis appears to be promising. However, similar to other micro-extraction techniques, such as solid phase micro-extraction (SPME), serious limitations still remain when analyzing semi-solid and solid environmental, food or biological matrices and/or highly polar compounds. Thus, other pre-concentration techniques may be a good alternative if an analytical problem cannot be sufficiently dealt with LPME.

The use of microextraction techniques for the analysis of pesticide residues in fruits, vegetables and other contaminants have become very popular due to its environmental friendly nature. Modern trends in sample preparation and subsequent instrumental analysis are aimed towards reliable and accurate analysis of fruits and vegetables. It is focused on the simplifications, miniaturization and improvement and reduction in volume of sample and solvents used while maintaining high throughput performance. The microextraction techniques have been developed, in order to reduce sample preparation time, improve sensitivity and selectivity as well as to corroborate the recent advances in the development of highly sensitive and efficient analytical instrumentations. The combination of several novel microextraction techniques to gas chromatography (GC), liquid chromatography (LC) and capillary electrophoresis (CE) has helped in the analysis of pesticides residues in various food matrices with little or no interferences from the complex food matrices. This paper reviews the methodology, advantages and disadvantages of different microextraction techniques used in the analysis of pesticide residues from fruits and vegetables.

Journal of Applied Sciences and Environmental Management, 2017

A headspace solid-phase microextraction (HS-SPME) method was developed as a preliminary investigation using univariate approach for the analysis of 14 multiclass pesticide residues in fruits and vegetable samples. The gas chromatography mass spectrometry parameters (desorption temperature and time, column flow rate, interface temperature) and solid phase microextraction parameters (fiber coating type, extraction temperature and time, pH, salt addition, stirring rate, dilution factor, organic solvent type and amount) were all investigated and optimized. The optimum values for the optimized parameters are as follows:

Microchimica Acta, 2012

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.

INDIAN JOURNAL OF LIFE SCIENCES, 2014

Pesticide agrochemicals have long been used for crop protection to improve agricultural productivity. Wide ranges ofpesticide combinations have been developed so as to restrain fast evolving pest spectrum. Multiclass pesticide combinations usedfor crop treatment create problem of persistence in the agro-environment posing potential health hazard to the consumer andecosystem. This accentuates need for development of efficient pesticide multiresidue methods for risk evaluation. Newer trends inanalysis of pesticides in food intend at use of solvent minimized extractions with scope of automation and hyphenation to bringfast, accurate and sensitive analysis. Accelerated extraction techniques based on microwave, ultrasonication and microsolventapproaches such as liquid phase, solid phase microextraction LPME, SPME respectively; underlies the objectives of greenanalysis as well provide scope for integration. Additionally, these novel 'solvent- free' extraction methods vouch for their efficacyand selectivity in comparison to their 'classical' counterparts. Present paper extensively updates developments in modern,assisted instrumental extraction approaches along with novel aspects of microextraction techniques introduced in pesticidemultiresidue analysis of foods. Noteworthy advantages and pitfalls of extraction modules based on these techniques are also evaluated.

Fungicides are a group of pesticides which are widely used and have negative effects on human health and the environment; Pesticide residues resulted from applying fungicides is a very important issue due to environmental pollution and human health risk and should be seriously considered. In order to achieve such insight summing up the dangers of pesticides is necessary so that attributes to predict social costs and benefits and monitor new policies applied. In this study, the possibility of extracting Triazole, a fungicide was evaluated by utilizing nanostructures, PW/SiO2, using new synthetic microextraction methods. Triazole is one of the most important pesticides with worldwide use for the protection of a variety of vegetables, fruits and grains and the destruction of many fungal pathogens because of its broad-spectrum and systemic properties. In this study, a new synthetic microextraction is used in which the PW/SiO2 with nano-holes is applied for extraction and identification Triazole; the high specific surface area, selectivity, shape and size are the main characteristics of these compounds leading to numerous catalytic applications, filtration, separation and extraction of pesticides. The optimization conditions for this process include the extraction temperature: 80° C, extraction duration: 45 minutes, desorption temperature: 300° C, desorption duration: 2 minutes. Also, the correlation coefficient was high (0.998) and linear range was broad (0.01 to 200 ng/ml).

Chromatographia, 2014