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: By using magnetic graphitized carbon black and primary secondary amine (GCB/PSA/MNPs) as adsorbent, a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was proposed for pesticide residue analysis in vegetables. The magnetic adsorbent was fabricated via simple co-mixing method based on an "aggregate warp" mechanism. To achieve the optimum conditions of modified QuEChERS toward target analytes, several parameters, including the composition of analyte protectants and the amount of the adsorbents were investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 10 pesticide residues in vegetables was established by coupling modified QuEChERS to gas chromatography/mass spectrometry analysis. The detection limits of the proposed method for 10 pesticides ranged from 0.39 to 8.6ng/g. Good linearity (R value≥0.990) was achieved at concentration levels of 10-200ng/g, and acceptable method reproducibility was found as intra- and inter-day precisions, yielding the relative standard deviations less than 10.7% and 13.4%, respectively. The recoveries were in the range of 69.9-125.0% at different concentrations for real samples. Compared with the reported methods for the determination of a large number of samples, the proposed method has the advantage of less time-consuming in clean-up procedure.Journal of Chromatography A 04/2013; · 4.61 Impact Factor
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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: The objective of this study was to develop analytical method based on optimized dispersive liquid-liquid microextraction (DLLME) as a pretreatment procedure combined with reversed phase liquid chromatographic separation on C18 column and isocratic elution for simultaneous MS/MS determination of selected neonicotinoid insecticides in honey. The LC-MS/MS parameters were optimized to unequivocally provide good chromatographic separation, low detection (LOD, 0.5-1.0μgkg(-1)) and quantification (LOQ, 1.5-2.5μgkg(-1)) limits for acetamiprid, clothianidin, thiamethoxam, imidacloprid, dinotefuran, thiacloprid and nitenpyram in honey samples. Using different types (chloroform, dichloromethane) and volumes of extraction (0.5-3.0mL) and dispersive (acetonitrile; 0.0-1.0mL) solvent and by mathematical modeling it was possible to establish the optimal sample preparation procedure. Matrix-matched calibration and blank honey sample spiked in the concentration range of LOQ-100.0μgkg(-1) were used to compensate the matrix effect and to fulfill the requirements of SANCO/12495/2011 for the accuracy (R 74.3-113.9%) and precision (expressed in terms of repeatability (RSD 2.74-11.8%) and within-laboratory reproducibility (RSDs 6.64-16.2%)) of the proposed method. The rapid (retention times 1.5-9.9min), sensitive and low solvent consumption procedure described in this work provides reliable, simultaneous, and quantitative method applicable for the routine laboratory analysis of seven neonicotinoid residues in real honey samples.Talanta 07/2013; 111C:125-33. · 3.50 Impact Factor