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  • 1
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Soil samples ; Microwave-assisted solvent extraction ; Nitrogen detection ; Triazine herbicides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Recent work demonstrated that the combination of microwave assisted solvent extraction (MASE) and capillary gas chromatography with selective nitrogen detection (GC-NPD) is a viable approach for the efficient determination of triazine herbicides in soils. However, for soils with a high organic matter content or the injection of more concentrated extracts to obtain lower LOD's the performance of gas chromatographic analysis of uncleaned extracts is hampered. This results in both a decrease of the chromatographic response of analytes and a decrease in the life time of the column due to coextracted matrix substances. The effect of various types of soils on the chromatographic analysis of triazine herbicides was studied. It appeared that for the investigated samples with an organic matter content below 5% processing of uncleaned extracts is possible. Samples with a higher organic matter content required a cleanup step. A rapid procedure on 100 mg silica cartridges has been developed using solvents compatible with the MASE extracts and the instrumental analysis. Beside the testing with different standard soils, about 120 samples of an ongoing monitoring program involving three different types of soil (organic matter content: 3–37%) were analysed. The selected compounds atrazine, desethylatrazine, desisopropyl-atrazine and simazine could be assayed in the various soil types to a level of at least 2 μg kg−1. For soil samples with a high organic matter content (〉5%), the rapid cleanup procedure allowed the trace analysis of the triazines and considerably increased the life time of the capillary column. Recoveries at levels from 2 to 50 μg kg−1 ranged from 70 to 100% with RSDs ranging from 5.1 to 9.5%. Confirmation of positive samples was carried out by gas chromatography mass spectrometry.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Microwave-assistend solvent extraction (MASE) ; Pesticide residue analysis ; Triazine herbicides ; Soil samples
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The use of microwave-assisted solvent extraction (MASE) as an alternative for conventional solvent extraction procedures for the determination of some triazine herbicides in soil samples has been investigated. In this study MASE method development was focused on the selection of a suitable extraction solvent prior to the instrumental analysis of uncleaned extracts with gas chromatography and nitrogen-specific detection. A mixture of dichloromethane-methanol (90∶10, v/v) yielded recoveries ranging from 89 to 103 (spiked level 200 μg/kg) with RSDs ranging from 2.1 to 5.3%. This solvent mixture is also very convenient for further procedure. The selected MASE procedure was tested by analyzing freshly spiked soil samples and samples with aged residues of atrazine, desethylatrazine, desisopropylatrazine and simazine. The results were compared with those obtained by a conventional liquid extraction method. The comparative study indicated that MASE yields recoveries at least as good as those obtained by the conventional method. Moreover, the MASE procedure provides low solvent consumption in combination with a high sample throughput.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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