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Cai M.-Q.,Zhejiang GongShang University | Wei X.-Q.,Zhejiang GongShang University | Du C.-H.,Zhejiang GongShang University | Ma X.-M.,Zhejiang GongShang University | And 2 more authors.
Journal of Chromatography A | Year: 2014

A novel amphiphilic polymeric ionic liquid membrane containing a hydrophilic bromide anion and a hydrophobic carbonyl group was synthesized in dimethylformamide (DMF) systems using the ionic liquid 1-butyl-3-vinylimidazolium bromide (BVImBr) and the methylmethacrylate (MMA) as monomers. The prepared amphiphilic ploy-methylmethacrylate-1-butyl-3-vinylimidazolium bromide (MMA-BVImBr) was characterized by a scanning electron microscope and an infrared spectrum instrument. The results of solid-phase micro-extraction membrane (SPMM) experiments showed that the adsorption capacity of membrane was about 0.76μgμg-1 for aniline. Based on this, a sensitive method for the determination of trace aniline, as a degradation product of azo dye Orange G under sonication, was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The calibration curve showed a good linearity ranging from 0.5 to 10.0μgL-1 with a correlation coefficient value of 0.9998. The limit of quantification was 0.5μgL-1. The recoveries ranged from 90.6% to 96.1%. The intra- and inter-day relative standard deviations were less than 8.3% and 10.9%. The developed SPMM-LC-MS/MS method was used successfully for preconcentration of trace aniline produced during the sonication of Orange G solution. © 2014 Elsevier B.V.. Source

Shi J.,Ningbo Key Laboratory of Poison Research and Control
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui | Year: 2010

A method for the simultaneous analysis of 43 pesticide residues in vegetables by gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS/MS) was developed and validated. The samples were extracted with acetonitrile, and then purified by solid-phase extraction (SPE). The detection of 43 pesticides was carried out by GC-QqQ-MS/MS in the multi-reaction monitoring (MRM) mode using external standard method. The overall recoveries determined at three spiked levels of 10, 80 and 100 microg/kg were 62.2%-170.0%, which in the recoveries of 36 pesticides were 70.0%-120.0%. The relative standard deviations (RSDs) were less than 18%. The limits of quantification (S/N > or =10) were 0.3-4.4 microg/kg. The method possesses low background and high sensitivity. It can be applied to the routine analysis of the 43 pesticides in vegetables. Source

Cai M.,Zhejiang GongShang University | Jin M.,Ningbo Key Laboratory of Poison Research and Control | Weavers L.K.,Ohio State University
Ultrasonics Sonochemistry | Year: 2011

In this paper, seven new sonolytic degradation products of Orange G were found and identified using powerful analytical techniques such as liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS), tandem mass spectrometry (MS/MS), and liquid chromatography with diode-array detection (LC-DAD). Each technique provided complementary information for the degradation products identification. In order to resolve the MS and MS/MS spectra obtained, the separation conditions were optimized. Among them, Orange G was unambiguously identified based on its abundant [M-H] - ion, [M + H] + ion, ultra-violet and visible spectra, retention time, and tandem mass spectrometric analysis compared with an authentic standard. The seven new degradation products were tentatively identified based on ultra-violet and visible spectra, [M-H] - ions, and tandem mass spectrometry. The neutral losses of SO 2, SO 3, N 2 and H 2O for MS/MS spectra which appear to be characteristic of the negative ion mode were observed. Based on this by-product identification, a possible multi-step degradation scheme is proposed. The analysis results of degradation products reveal that the degradation mechanism proceeds via reductive cleavage of the azo linkage, as well as intermolecular dehydration and desulfonation due to the powerful oxidizing hydroxyl radicals as well as hydrogen radical. © 2011 Elsevier B.V. All rights reserved. Source

Cai M.Q.,Zhejiang GongShang University | Cai M.Q.,U.S. Center for Disease Control and Prevention | Wei X.Q.,Zhejiang GongShang University | Song Z.J.,Zhejiang GongShang University | And 2 more authors.
Ultrasonics Sonochemistry | Year: 2015

In this work, the decolorization of azo dye Orange G (OG) in aqueous solution by aluminum powder enhanced by ultrasonic irradiation (AlP-UI) was investigated. The effects of various operating operational parameters such as the initial pH, initial OG concentration, AlP dosage, ultrasound power and added hydrogen peroxide (H2O2) concentration were studied. The results showed that the decolorization rate was enhanced when the aqueous OG was irradiated simultaneously by ultrasound in the AlP-acid systems. The decolorization rate decreased with the increase of both initial pH values of 2.0-4.0 and OG initial concentrations of 10-80 mg/L, increased with the ultrasound power enhancing from 500 to 900 W. An optimum value was reached at 2.0 g/L of the AlP dosage in the range of 0.5-2.5 g/L. The decolorization rate enhanced significantly by the addition of hydrogen peroxide in the range of 10-100 mM to AlP-UI system reached an optimum value of 0.1491 min-1. The decolorization of OG appears to involve primarily oxidative steps, the cleavage of NN bond, which were verificated by the intermediate products of OG under the optimal tested degradation system, aniline and 1-amino-2-naphthol-6,8- disulfonate detected by the LC-MS. © 2014 Elsevier B.V. All rights reserved. Source

Yao X.-P.,Ningbo Key Laboratory of Poison Research and Control | Fu Z.-J.,Linzhou Institute for Food and Drug Control | Zhao Y.-G.,Ningbo Key Laboratory of Poison Research and Control | Wang L.,Ningbo Key Laboratory of Poison Research and Control | And 2 more authors.
Talanta | Year: 2012

A new method that utilizes tetraethylenepentamine-functional Fe 3O 4 magnetic polymers (TEPA-NMPs) as a solid-phase extractant for matrix solid phase dispersion extraction (MSPD) has been developed for preconcentration of Cr(VI) at ultratrace levels prior to the measurement by flame atomic absorption spectroscopy (FAAS). The separation/preconcentration conditions of Cr(VI) was investigated, including the pH value, shaking time, adsorption temperature, sample volume, desorption conditions and interfering ions. The results showed the adsorption properties of the TEPA-NMPs were highly pH dependent. The data of adsorption kinetics obeyed pseudo-second-order rate mechanism well. Adsorption thermodynamic studies suggested that the adsorption processes of Cr(VI) onto the TEPA-NMPs was endothermic and entropy favored in nature. Under the best experimental conditions, the enhancement factor was 125 times, the detection limit of the method was 0.16 μg L -1 and the relative standard deviation was 1.9% (n=7). Furthermore, the developed method was validated by comparing with Graphite Furnace atomic absorption spectrometry (GF-AAS) method, and has been applied for the determination of ultratrace Cr(VI) ions in the river and tap water samples with satisfactory results, which revealed the sensitivity of the proposed TEPA-NMPs MSPD-FAAS method was comparable with that of GF-AAS method. © 2012 Elsevier B.V. All rights reserved. Source

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