Co-reporter:Lijie Wu, Mingzhu Hu, Zhanchao Li, Ying Song, Cui Yu, Hanqi Zhang, Aimin Yu, Qiang Ma, Ziming Wang
Food Chemistry 2016 Volume 192() pp:596-602
Publication Date(Web):1 February 2016
DOI:10.1016/j.foodchem.2015.07.055
•A novel DMAE–CFME was firstly assembled and validated for extraction of OPPs in vegetables.•Extraction, separation, and enrichment were finished in a simple step.•The method extends the application of the SDME in complex solid matrixes.•No further filtration or cleanup was required before analysis by GC–MS.•The developed method is simple, rapid, solventless and cost-effective.A simple, rapid, solventless and cost-effective dynamic microwave-assisted extraction (DMAE) combined with continuous-flow microextraction (CFME) system was firstly assembled and validated for extraction of eight organophosphorus pesticides in vegetables. The method combines the advantages of DMAE and CFME, and extends the application of the single drop microextraction to complex solid samples. The extraction, separation, and enrichment were performed in a single step, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, analytes were first extracted from the vegetables using 3% NaCl solution as extraction solvent, then concentrated into microextraction solvent. After extraction, the microextraction solvent containing the enriched analyte was directly analyzed by GC–MS without any filtration or clean-up process. Several parameters affecting the extraction efficiency were investigated and optimized. Real vegetable samples were analyzed, satisfactory recoveries were obtained in the range of 80.7–106.7%, and relative standard deviations were lower than 8.7%.
Co-reporter:Lijie Wu, Ying Song, Mingzhu Hu, Hanqi Zhang, Aimin Yu, Cui Yu, Qiang Ma, Ziming Wang
Food Chemistry 2015 Volume 176() pp:197-204
Publication Date(Web):1 June 2015
DOI:10.1016/j.foodchem.2014.12.055
•A novel MSB-LPME was first applied for determination of OPPs in juice samples.•The MSB-LPME device was cheaply manufactured and easily assembled.•The magnetic solvent bar can be used to stir and extract the analytes.•This smart MSB can make the operation of sample treatment be simplified.•The magnetic solvent bar is easier isolated from the sample.A simple, rapid and sensitive sample pretreatment technique, magnetic solvent bar liquid-phase microextraction (MSB-LPME) was developed for extracting organophosphorus pesticides from fruit juice. The analytes were extracted from the sample to the organic solvent immobilized in the fiber. The magnetic solvent bar not only can be used to stir the samples but also extract the analytes. After extraction, the analyte-adsorbed magnetic solvent bar can be readily isolated from the sample solution by a magnet, which could greatly simplify the operation and reduce the whole pretreatment time. The bar was eluted with methanol. The elute was evaporated to dryness and residue was dissolved in hexane. Several experimental parameters were investigated and optimized, including type of extraction solvent, number of magnetic solvent bar, extraction temperature, extraction time, salt concentration, stirring speed, pH and desorption conditions. The recoveries were in the range of 81.3–104.6%, and good reproducibilities were obtained with relative standard deviation below 6.1%.
Co-reporter:Lijie Wu, Mingzhu Hu, Zhanchao Li, Ying Song, Hanqi Zhang, Aimin Yu, Qiang Ma, Ziming Wang
Journal of Chromatography A 2015 Volume 1407() pp:42-51
Publication Date(Web):14 August 2015
DOI:10.1016/j.chroma.2015.06.062
•A DMAE-SDME system was assembled for determination of OPPs in tea.•The method makes extraction, cleanup, separation, and enrichment to be carried out in one step.•The method extends the application of the SDME in complex solid matrixes.•No further filtration or cleanup was required before analysis by GC–MS.•A Box–Behnken design was applied to study the possible interaction between the parameters.A new method for the determination of seven organophosphorus pesticides was developed using dynamic microwave-assisted extraction online coupled with single drop microextraction prior to gas chromatographic mass spectrometry (GC–MS). The method combines the advantages of dynamic microwave-assisted extraction and single-drop microextraction, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, tea samples were extracted with 25% ethanol aqueous solution and purified with acidic alumina at the same time, and then the analytes were concentrated into microextraction solvent. When the extraction was completed, the solvent microdrop containing the enriched analytes was retracted into the microsyringe and directly analyzed by GC–MS without any filtration or cleanup step. The method makes extraction, cleanup, separation, and enrichment to be carried out in one step. Several experimental parameters, including type of extraction solvent, type and amount of dispersant, type and volume of microextraction solvent, microwave power, extraction time, and flow rate of extraction solvent were investigated and optimized. Under optimal experimental conditions, good linearity was observed in the range of 2.00–500.00 μg kg−1. The limits of detection and quantification were in the range of 0.4–1.7 μg kg−1 and 1.1–5.6 μg kg−1, respectively. The present method was applied to the analysis of tea samples, and the recoveries of analytes were in the range of 84.9–106.4% with the relative standard deviations ranging from 1.0 to 6.1%. The results showed that the present method was a rapid and feasible method for the determination of organophosphorus pesticides in tea samples.
Co-reporter:Lijie Wu;Ying Song;Mingzhu Hu;Cui Yu;Hanqi Zhang;Aimin Yu;Qiang Ma
Journal of Separation Science 2015 Volume 38( Issue 17) pp:2953-2959
Publication Date(Web):
DOI:10.1002/jssc.201500039
Microwave-assisted ionic-liquid-impregnated resin solid–liquid extraction was developed for the extraction of triazine herbicides, including cyanazine, metribuzin, desmetryn, secbumeton, terbumeton, terbuthylazine, dimethametryn, and dipropetryn in honey samples. The ionic-liquid-impregnated resin was prepared by immobilizing 1-hexyl-3-methylimidazolium hexafluorophosphate in the microspores of resin. The resin was used as the extraction adsorbent. The extraction and enrichment of analytes were performed in a single step. The extraction time can be shortened greatly with the help of microwave. The effects of experimental parameters including type of resin, type of ionic liquid, mass ratio of resin to ionic liquid, extraction time, amount of the impregnated resin, extraction temperature, salt concentration, and desorption conditions on the extraction efficiency, were investigated. A Box–Behnken design was applied to the selection of the experimental parameters. The recoveries were in the range of 80.1 to 103.4% and the relative standard deviations were lower than 6.8%. The present method was applied to the analysis of honey samples.
Co-reporter:Mingzhu Hu, Lijie Wu, Ying Song, Zhanchao Li, Qiang Ma, Hanqi Zhang and Ziming Wang
Analytical Methods 2015 vol. 7(Issue 21) pp:9114-9120
Publication Date(Web):22 Sep 2015
DOI:10.1039/C5AY01963J
Microwave-assisted liquid–liquid microextraction based on solidification of floating organic droplet (MA-LLME-SFO) was first developed and applied to the extraction of triazines in honey samples. 1-Dodecanol, which is of low toxicity, low density and has an appropriate melting point near room temperature, was chosen as the extraction solvent. Furthermore, traditional organic dispersive solvents were avoided in this method with the aid of microwave irradiation. Several experimental parameters, including the type and volume of extraction solvent, microwave power and irradiation time, pH of the sample solution, ionic strength and centrifugation rate were investigated and optimized. The proposed method showed a good linearity within the range of 5.00–250.00 μg kg−1 with the correlation coefficients ranging from 0.9994 to 0.9998. The limits of detection for cyanazine, desmetryn, terbuthylazine and dimethametryn were 1.39, 0.95, 1.20, and 1.07 μg kg−1, respectively. The recoveries of the analytes ranged from 74.84 to 112.74% and the relative standard deviations were lower than 13.10%, when the present method was applied to the analysis of real samples.
Co-reporter:Ying Song, Lijie Wu, Na Li, Mingzhu Hu, Ziming Wang
Talanta 2015 Volume 135() pp:163-169
Publication Date(Web):1 April 2015
DOI:10.1016/j.talanta.2014.12.049
•A novel MA-HILME method was first developed.•No special equipment was needed and the phase separation was simple.•The proposed method was simple, rapid, economic and environmental friendly.•The developed procedure was used in the analysis of Sudan dyes in red wines.A novel microwave-assisted homogeneous ionic liquid microextraction (MA-HILME) method was first developed for the extraction of Sudan dyes in red wines followed by detection using high-performance liquid chromatography. 1-dodecyl-3-methylimidazolium bromide ([C12MIM]Br) was used as extractant in a microwave-assisted extraction (MAE) procedure, and then transferred into hydrophobic solid-state ionic liquid after adding ammonium hexafluorophosphate ([NH4][PF6]). The separation between liquid state sample and solid state extractant can be realized easily. Several experimental parameters, including type and amount of extraction solvent, microwave power and irradiation time, amount of ion-exchange reagent ([NH4][PF6]), pH of sample solution, and ionic strength, were evaluated. Under the optimum experimental conditions, the linearity for the determining of the analytes was in the range of 0.5–100 μg L−1, with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for Sudan I, Sudan II, Sudan III, and Sudan IV were 0.19, 0.18, 0.24, and 0.16 μg L−1, respectively. When the present method was applied to the determination of Sudan dyes in red wines, satisfactory recoveries were obtained in the range of 78.5–106.8%, and relative standard deviations were lower than 9.7%.
Co-reporter:Lijie Wu, Ying Song, Mingzhu Hu, Xu Xu, Hanqi Zhang, Aimin Yu, Qiang Ma, Ziming Wang
Talanta 2015 Volume 134() pp:366-372
Publication Date(Web):1 March 2015
DOI:10.1016/j.talanta.2014.11.035
•An integrated microwave processing system was first assembled for extraction of OPPs in fresh vegetables.•The method has the advantages of both DMAE and MASE technique.•Extraction, separation, enrichment and elution were finished in a simple step.•The active carbon fiber has god adsorption ability and desorption ability.•No further filtration or cleanup was required before analysis by GC–MS.A simple and efficient integrated microwave processing system (IMPS) was firstly assembled and validated for the extraction of organophosphorus pesticides in fresh vegetables. Two processes under microwave irradiation, dynamic microwave-assisted extraction (DMAE) and microwave-accelerated solvent elution (MASE), were integrated for simplifying the pretreatment of the sample. Extraction, separation, enrichment and elution were finished in a simple step. The organophosphorus pesticides were extracted from the fresh vegetables into hexane with DMAE, and then the extract was directly introduced into the enrichment column packed with active carbon fiber (ACF). Subsequently, the organophosphorus pesticides trapped on the ACF were eluted with ethyl acetate under microwave irradiation. No further filtration or cleanup was required before analysis of the eluate by gas chromatography–mass spectrometry. Some experimental parameters affecting extraction efficiency were investigated and optimized, such as microwave output power, kind and volume of extraction solvent, extraction time, amount of sorbent, elution microwave power, kind and volume of elution solvent, elution solvent flow rate. Under the optimized conditions, the recoveries were in the range of 71.5–105.2%, and the relative standard deviations were lower than 11.6%. The experiment results prove that the present method is a simple and effective sample preparation method for the determination of pesticides in solid samples.
Co-reporter:Lijie Wu, Ying Song, Xu Xu, Na Li, Mingyuan Shao, Hanqi Zhang, Aimin Yu, Cui Yu, Qiang Ma, Chunmei Lu, Ziming Wang
Food Chemistry 2014 Volume 162() pp:253-260
Publication Date(Web):1 November 2014
DOI:10.1016/j.foodchem.2014.04.057
•A MA-NPS-DME system was assembled for determination of OPPs in cereals.•A microwave extractor was made and used to heat samples directly.•The microwave extractor can be reused.•The MAM can be recycled and was not in contact with the samples.•Only non-polar solvent was applied to the extraction of OPPs.A fast and green pretreatment method, medium-assisted non-polar solvent dynamic microwave extraction, was first applied to extract ten of organophosphorus pesticides (OPPs) from five cereal samples. Without adding any polar solvent, graphite powders (GP) were used as microwave absorption medium to transform microwave energy into heat energy. For recycling GP, an extractor was made by sealing GP inside the exterior tube of a glass sleeve. By dynamic microwave extraction using hexane as extraction solvent, ten OPPs could be extracted completely within 200 s, and the extract was directly analysed by GC–MS without any clean-up process. The effects of some experimental parameters on extraction efficiency were investigated and optimised. Relative standard deviations of intra- and inter-day ranging from 1.02% to 5.32% were obtained. Five real samples were analysed, and the recoveries obtained were in the range of 73.2–99.8%, and the relative standard deviations were lower than 6.63%.
Co-reporter:Ying Song;Lijie Wu;Chunmei Lu;Na Li;Mingzhu Hu
Journal of Separation Science 2014 Volume 37( Issue 23) pp:3533-3538
Publication Date(Web):
DOI:10.1002/jssc.201400837
An easy, quick, and green method, microwave-assisted liquid–liquid microextraction based on solidification of ionic liquid, was first developed and applied to the extraction of sulfonamides in environmental water samples. 1-Ethy-3-methylimidazolium hexafluorophosphate, which is a solid-state ionic liquid at room temperature, was used as extraction solvent in the present method. After microwave irradiation for 90 s, the solid-state ionic liquid was melted into liquid phase and used to finish the extraction of the analytes. The ionic liquid and sample matrix can be separated by freezing and centrifuging. Several experimental parameters, including amount of extraction solvent, microwave power and irradiation time, pH of sample solution, and ionic strength, were investigated and optimized. Under the optimum experimental conditions, good linearity was observed in the range of 2.00–400.00 μg/L with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for sulfathiazole, sulfachlorpyridazine, sulfamethoxazole, and sulfaphenazole were 0.39, 0.33, 0.62, and 0.85 μg/L, respectively. When the present method was applied to the analysis of environmental water samples, the recoveries of the analytes ranged from 75.09 to 115.78% and relative standard deviations were lower than 11.89%.
Co-reporter:Ziming Wang, Xin Zhao, Xu Xu, Lijie Wu, Rui Su, Yajing Zhao, Chengfei Jiang, Hanqi Zhang, Qiang Ma, Chunmei Lu, Deming Dong
Analytica Chimica Acta 2013 760() pp: 60-68
Publication Date(Web):14 January 2013
DOI:10.1016/j.aca.2012.11.031
A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (μ-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave μ-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in μ-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave μ-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60 °C for 10 min. The extracts obtained by MAE-μ-SPE were directly analyzed by GC–MS without any clean-up process. The recoveries were in the range of 93.5–104.6%, and the relative standard deviations were lower than 8.7%.Graphical abstractHighlights► An absorbing microwave μ-SPE device packed with activated carbon was used. ► Absorbing microwave μ-SPE device was made and used to enrich the analytes. ► Absorbing microwave μ-SPE device was made and used to heat samples directly. ► MAE-μ-SPE was applied to the extraction of OPPs with non-polar solvent only.
Co-reporter:Xin Zhao, Xu Xu, Rui Su, Hanqi Zhang, Ziming Wang
Journal of Chromatography A 2012 Volume 1229() pp:6-12
Publication Date(Web):16 March 2012
DOI:10.1016/j.chroma.2012.01.018
A new self-designed microwave absorption tube was used in microwave-assisted extraction of seven organophosphorus pesticides from four kinds of vegetable samples. The non-polar solvent was used as extraction solvent, and a new portable microwave extraction apparatus was used. By sealing graphite powder in glass tube, microwave absorption tube was made and used to heat samples directly. The extracts were directly analyzed by GC–MS without any clean-up process. The effects of some experimental parameters on extraction efficiency were investigated and optimized. 3.0 g of sample, 25 mL of hexane and three microwave absorption tubes were added in the microwave extraction vessel, the extraction was carried out under 425 W irradiation power at 70 °C for 8 min. The recoveries were in the range of 76.5–109.4% and the relative standard deviations were lower than 13.1%.Highlights► A new self-designed microwave absorption tube was used for extracting OPPs. ► A new portable microwave extraction apparatus was used. ► Microwave absorption tube was made and used to heat samples directly. ► MAE was applied to the extraction of OPPs with non-polar solvent only.
Co-reporter:Mingzhu Hu;Lijie Wu;Ying Song;Zhanchao Li;Qiang Ma;Hanqi Zhang
Analytical Methods (2009-Present) 2015 - vol. 7(Issue 21) pp:NaN9120-9120
Publication Date(Web):2015/10/22
DOI:10.1039/C5AY01963J
Microwave-assisted liquid–liquid microextraction based on solidification of floating organic droplet (MA-LLME-SFO) was first developed and applied to the extraction of triazines in honey samples. 1-Dodecanol, which is of low toxicity, low density and has an appropriate melting point near room temperature, was chosen as the extraction solvent. Furthermore, traditional organic dispersive solvents were avoided in this method with the aid of microwave irradiation. Several experimental parameters, including the type and volume of extraction solvent, microwave power and irradiation time, pH of the sample solution, ionic strength and centrifugation rate were investigated and optimized. The proposed method showed a good linearity within the range of 5.00–250.00 μg kg−1 with the correlation coefficients ranging from 0.9994 to 0.9998. The limits of detection for cyanazine, desmetryn, terbuthylazine and dimethametryn were 1.39, 0.95, 1.20, and 1.07 μg kg−1, respectively. The recoveries of the analytes ranged from 74.84 to 112.74% and the relative standard deviations were lower than 13.10%, when the present method was applied to the analysis of real samples.
