Modern Extraction Techniques for Pesticide Residues Determination in Plant and Soil Samples

Abstract

Due to intensive use of pesticides, their residues have become an unavoidable part of environment, and they are often detected in all environmental segments and therefore their monitoring has been frequently performed throughout world. As presence of trace amounts of both pesticide residues and their degradation products could be potential health hazards, UN organization has formed specialized groups: World Health Organization (WHO) and Food Agriculture Organization (FAO), with aim to establish restrictive measures to protect environment against pollution. These organizations and their experts groups on annual meetings summarize international achievements in pesticides domain, establish legislation and make recommendations obligating member states to act in accordance with international standards. As pesticides are a very heterogeneous group of compounds with different biological and physicochemical properties, current trend in pesticide residues analysis is developing multi-residual methods that not only provide simultaneous determination of large number of pesticides, but also can be applicable to large numbers of samples of different origin. Although separation chemical analysis involves several stages (sample preparation, analyte separation i.e. quantification and data analysis), sample preparation step can be marked as the most critical one. Traditional sample preparation methods (liquid-liquid extraction, Soxhlet extraction, etc.) are laborious, time consuming, expensive, requires large amounts of organic solvents and usually involve many steps, leading to loss of some analyte quantity. Additionally, consequences of hydrocarbon solvents use, such as ozone depletion and generation of considerable cancer waste, lead to reduction of not only their use but also their manufacture. As a result, modern sample preparation procedures, such as accelerated solvent extraction (ASE), supercritical fluid extraction (SFE), microwave assisted extraction (MAE), solid phase extraction (SPE), solid phase microextraction (SPME), matrix solid phase dispersion (MSPD) extraction and QuEChERS (quick, easy, cheap, effective, rugged and safe), have been developed to overcome drawbacks of traditional approaches. It should be indicated that SFE, ASE and MAE are instrumental techniques, and often use SPE and SPME for purification of obtained extracts, and also its concentration in case of SPME. Overall, a comprehensive analytical procedure is carried out in way that obtained results can be found within prior established concentration range. Whether measurement will