Microwave-assisted derivatization of acidic herbicides for gas chromatography-mass spectrometry.
Microwave radiation is used to speed up chemical derivatization. In the present study, three microwave-assisted techniques for the methylation of chlorophenoxy acid herbicides prior to analysis by gas chromatography coupled with mass spectrometry are compared. Derivatization was performed with the catalysts sulphuric acid and boron trifluoride as well as with trimethylsilyldiazomethane. In order to establish optimized and stable conditions, a screening for statistically significant factors by means of experimental designs was carried out and supplemented by a careful optimization. Special emphasis has been given to an accurate validation to prove the performance of the techniques. Furthermore, all microwave-assisted methods were compared with their conventional analogues. The optimized methods are valid for routine analysis of different matrices such as water, soil, sediment or tissues, especially for high sample throughput since a simultaneous derivatization of up to 64 samples in one run is possible.
Ranz
Andreas
A
Institute of Analytical Chemistry and Radiochemistry, Graz University of Technology, Technikerstrasse 4, 8010 Graz, Austria.
Eberl
Anita
A
Maier
Eveline
E
Lankmayr
Ernst
E
D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis; D000143:Acids; D001880:Boranes; D003978:Diazomethane / Q000031:analogs & derivatives; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000032:analysis*; D007202:Indicators and Reagents; D000432:Methanol / Q000737:chemistry; D008745:Methylation; D008872:Microwaves; D011786:Quality Control; D012015:Reference Standards; D012997:Solvents; D013464:Sulfuric Acids / Q000737:chemistry; D014297:Trimethylsilyl Compounds
D000143:Acids; D001880:Boranes; D004952:Esters; D006540:Herbicides; D007202:Indicators and Reagents; D012997:Solvents; D013464:Sulfuric Acids; D014297:Trimethylsilyl Compounds; D015084:2,4-Dichlorophenoxyacetic Acid; D003978:Diazomethane; C021274:boron trifluoride; C033158:sulfuric acid; C060070:trimethylsilyldiazomethane; D000432:Methanol