Application of gas chromatography-hybrid chemical ionization mass spectrometry to the analysis of diclofenac in wastewater samples.
(2006)
Journal - Journal of chromatography. A (Netherlands )
Abstract :
Hybrid chemical ionization (HCI), a new and useful alternative to conventional chemical ionization mass spectrometry, has been applied to the analysis of the pharmaceutical diclofenac in wastewater samples. This technique takes advantage of the high versatility of ion trap (IT) spectrometers combined with external ionization sources. In hybrid configuration, reagent ions are generated in the external source through electron ionisation (EI) of a reagent gas. These reagent ions are then drawn into the ion trap and only those selected are allowed to react with analytes eluting from the GC column. These ion-molecule reactions create analyte ions which are held in the ion trap. In this study ion-molecule reactions between C(3)F(5)(+) cations, generated from perfluorotributylamine (FC43), and diclofenac molecules have been investigated. The observed reaction products were [M+C(3)F(5)-H(2)O](+) adduct ions, which result from the initial electrophilic addition of C(3)F(5)(+) cations to the diclofenac molecule followed by the rapid loss of H(2)O. Further fragmentation of these ions by MS/MS yielded enough daughter ions for a reliable identification of diclofenac in complex matrices. The GC-HCI-MS/MS method applied to wastewater samples provided highly enhanced selectivity and sensibility, with a detection limit in real samples of 3.0 ng/L, for a solid-phase extraction (SPE) pre-concentration factor of 400. Other performance characteristics of the method, such as linearity and precision were also satisfactory. Finally, the method was successfully applied to the analysis of wastewater samples taken from the effluent of an urban sewage treatment plant (STP).
| ISSN : | 0021-9673 |
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| Mesh Heading : | Chromatography, Gas Diclofenac Mass Spectrometry Reproducibility of Results Sewage Software Water Pollutants, Chemical chemistry analysis chemistry |
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| Mesh Heading Relevant : | methods analysis methods chemistry analysis |
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One-year routine application of a new method based on liquid chromatography-tandem mass spectrometry to the analysis of 16 multiclass pesticides in vegetable samples.
(2004)
Journal - Journal of chromatography. A (Netherlands )
Abstract :
An analytical procedure has been developed for determining a group of 16 multiclass pesticides most commonly used in crop protection. The extraction step is performed with a mixture of ethyl acetate and sodium sulphate, in the presence of 6.5 M NaOH. After evaporation, a final extract containing 1 mg sample/ml extract, is obtained in methanol. Analysis of the methanolic extract, without additional clean-up steps, is performed by liquid chromatography-electrospray ionisation-tandem mass spectrometry combining positive and negative ion mode. The analytical performance of the method has been validated for three different matrices: pepper, lettuce and aubergine. Mean recoveries obtained were between 70 and 110% in most of the cases with a precision of <28%. Linearity of response over 2 orders of magnitude was demonstrated (r > or = 0.99) with limits of detection < or = 0.01 mg/kg in all the cases. No significant matrix effects were observed with the exception of triflumizol that presented a drastic decrease in response as a consequence of an ion formation suppression effect in the presence of pepper matrix. The method has been applied to the analysis of 560 vegetable samples, as a part of the monitoring programme of the Association of Producers and Exporters of Fruits and Vegetables of Almería (COEXPHAL). The unambiguous confirmation of the positive findings by comparison of the product ion mass spectra of the peaks in samples and standards, demonstrated the applicability of the method in routine analysis.
| ISSN : | 0021-9673 |
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| Mesh Heading : | Chromatography, Liquid Pesticides Quality Control Reproducibility of Results Sensitivity and Specificity Spectrometry, Mass, Electrospray Ionization Vegetables |
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| Mesh Heading Relevant : | methods analysis methods chemistry |
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Multiresidue method for the analysis of multiclass pesticides in agricultural products by gas chromatography-tandem mass spectrometry.
(2002)
Journal - The Analyst (England )
Abstract :
A multiresidue method is described for determining 55 organophosphorus and organochlorinated compounds and pyrethroids commonly used in crop protection. Pesticide residues are extracted from samples with a mixture of ethyl acetate and sodium sulfate, obtaining a final preconcentration of I mg sample (ml extract)(-1). No additional clean-up steps are necessary. Analysis is performed by gas chromatography by using a combination of positive chemical ionisation (PCI) and electron impact (EI) ionisation modes and tandem mass spectrometry (GC-PCI/EI-MS-MS). Good sensitivity and selectivity of the method are obtained with limits of detection (LODs) ranging from 0.07 to 4.21 microg kg(-1) in all the cases, except for methamidophos, permethrin, cypermethrin and difenconazol. Average recoveries between 52 and 114% are obtained and good linearity is observed in the studied ranges (r > or = 0.994). The RSD values are < or = 29% in all the cases. The method has been applied to the analysis of 178 vegetable samples, as a part of the monitoring programme of the Association of Producers and Exporters of Fruits and Vegetables of Almería (COEXPHAL) and quality control systems applied during the assays have demonstrated a good performance and stability with time.
| ISSN : | 0003-2654 |
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| Mesh Heading : | Gas Chromatography-Mass Spectrometry Insecticides Pesticide Residues Spectrometry, Mass, Electrospray Ionization Vegetables |
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| Mesh Heading Relevant : | Food Contamination Hydrocarbons, Chlorinated analysis analysis |
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Splitless large-volume GC-MS injection for the analysis of organophosphorus and organochlorine pesticides in vegetables using a miniaturised ethyl acetate extraction.
(2000)
Journal - The Analyst (ENGLAND )
Abstract :
A simple, rapid and sensitive multiresidue method has been developed for the determination of ten organophosphorus and organochlorine pesticides, commonly used in crop protection. The analysis uses a miniaturised extraction with ethyl acetate followed by large volume injection (10 microL) GC-EI-MS analysis in SIM (selective ion monitoring) mode. Sensitivity and selectivity of the method were acceptable with limits of detection (LODs) lower than 0.01 mg kg-1, except for endosulfan alpha and beta (0.05 mg kg-1). Average recoveries of between 63-99% were obtained and good linearity was observed in the range from 0.01 to 1.00 mg kg-1. Repeatability and reproducibility studies yielded relative standard deviations lower than 20% in all the cases. The method was applied to the analysis of 110 tomato, pepper and cucumber samples, as part of the monitoring programme of the Association of Producers and Exporters of Fruits and Vegetables of Almería.
| ISSN : | 0003-2654 |
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| Mesh Heading : | Acetates Food Contamination Gas Chromatography-Mass Spectrometry Humans Insecticides Organophosphorus Compounds Pesticide Residues |
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| Mesh Heading Relevant : | Vegetables analysis analysis analysis |
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