Supercritical fluid extraction for pesticide multiresidue analysis in honey: determination by gas chromatography with electron-capture and mass spectrometry detection.
ABSTRACT An analytical procedure using supercritical fluid extraction (SFE) and capillary gas chromatography with electron-capture detection was developed to determine simultaneously residues of different pesticides (organochlorine, organophosphorus, organonitrogen and pyrethroid) in honey samples. Fortification experiments were conducted to test conventional extraction (liquid-liquid) and optimize the extraction procedure in SFE by varying the CO2-modifier, temperature, extraction time and pressure. Best efficiency was achieved at 400 bar using acetonitrile as modifier at 90 degrees C. For the clean-up step, Florisil cartridges were used for both methods LLE and SFE. Recoveries for majority of pesticides from fortified samples of honey at fortification level of 0.01-0.10 mg/kg ranged 75-94% from both methods. Limits of detection found were less than 0.01 mg/kg for ECD and confirmation of pesticide identity was performed by gas chromatography-mass spectrometry in selected-ion monitoring mode. The multiresidue methods in real honey samples were applied and the results of developed methods were compared.
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ABSTRACT: This review provides an updated discussion on the recent developments and applications of supercritical fluid technology in analytical chemistry. Supercritical mediums are usually used for extraction and separation of various analytes in analytical science. Although, this technology is used for chromatographic aims in the analysis of various samples the main application domain of supercritical fluids is in extraction process. SFE is suitable for recovery of various analytes, especially non-polar organic compounds, from different matrices. However, via some modifications or by the aid of modifiers or a chelating agent, this technique could be successfully applied in the extraction of polar or even ionic analytes. The range of analytes extracted via SFE is wide and mostly includes food and pharmaceutical samples, pollutants extraction and metal cation extraction. The aim of this paper is to review, from analytical chemistry standpoint, recent advances in the use of SC-CO2 for the extraction and separation of analytes. At the same time, a critical assessment will be made of the advantages of SCF technology in comparison with traditional methods. Special emphasis will be given to online coupling of SFE method with chromatographic techniques and FT-IR spectroscopy that make possible the extraction and separation of various analytes from different matrices in order to produce novel analytical techniques. The potentials, advantages, shortcomings, and prospects in employment of supercritical fluids for separation and extraction of various analytes are also considered. The efficiencies of SFE for the extraction of various analytes from solid and aqueous samples are compared to traditional methods such as Soxhlet extraction. Supercritical fluid extraction due to various reasons such as its greenness, rapidity and high efficiency are widely used an alternative to conventional solvent-based extraction methods. Also, SFE can be as an automated and miniaturized extraction technique, since it reduces the amounts of required samples considerably. SFE avoids multi-steps of conventional methods (such as partitioning, clean-up, evaporation) and hence it can reduce the uncertainty in the results. Furthermore, SFE reduces analysis times and is less laborintensive.Current Analytical Chemistry 01/2014; 10(1):3-28. · 1.56 Impact Factor
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ABSTRACT: Polydivinylbenzene (P-DVB) and silica monolithic materials were synthesised in capillaries and then used to adsorb nine organonitrogen pesticides extracted from honey. After adsorption, each monolith-capillary was connected to a gas chromatograph (GC) with nitrogen-phosphorous detector (NPD). The silica monolith gave better peak shape and intensity than the P-DVB monolith. Formulation of silica monolith with tetramethoxysilane (TMOS) as a sole initiator provided better separation and higher peak intensity, compared to those with methyltrimethoxysilane (MTMS) and (3:1) TMOS/MTMS initiators. The optimum internal diameter and length of silica monolith-capillary were 0.25 mm and 5 cm, respectively. The purge and trap conditions were optimised by purging with nitrogen and heating the honey sample solution at 100 °C for 60 min. Recovery of the method was in a range of 84.95-99.71% and the detection limits of the pesticides determined by using GC-NPD and GC-mass spectrometric detector (MSD) ranged between 0.36-1.75 and 0.13-0.25 ng g(-1), respectively.Analytical and Bioanalytical Chemistry 01/2012; 402(2):955-64. · 3.66 Impact Factor
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ABSTRACT: The objective of this work was to establish a simple extraction method for the residual analysis of pyraclofos and tebufenpyrad in Perilla leaves. A QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for extraction using ethyl acetate as an extraction solvent, and cleanup was carried out using dispersive solid-phase extraction technique. The samples were analyzed using gas chromatography with nitrogen phosphorous detector and confirmed by gas chromatography-mass spectrometry. The linearity was excellent (r(2) = 1.0) in matrix-matched calibration for both pesticides. The recoveries at two fortification levels were 80.76-95.38% with relative standard deviation lower than 5%. The limits of detection and limits of quantification were 0.01 and 0.033 mg/kg for both pesticides, respectively. The results revealed that the dissipation pattern of pyraclofos and tebufenpyrad followed first-order kinetics. The pyraclofos and tebufenpyrad residues declined to a level below the maximum residue limits within 14 day between the last application and harvesting. We suggest that pyraclofos and tebufenpyrad could be used efficiently on perilla leaves under the recommended dosage conditions. Copyright © 2012 John Wiley & Sons, Ltd.Biomedical Chromatography 06/2012; · 1.95 Impact Factor