Microwave assisted derivatization and quantification of glyphosate, glufosinate, and aminomethylphosphonic acid by GC-MS

BRENDA B. SLIZ; FIORELLA MENESTRINA; NICOLÁS R. RONCO; CECILIA B. CASTELLS; LEONARDO G. GAGLIARDI

Praga

Simposio; 45th Symposium on High Performance Liquid Phase Separations and related Techniques (HPLC 2017); 2017

p { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 0); line-height: 115%; }p.western { font-family: "Calibri",sans-serif; font-size: 11pt; }p.cjk { font-family: "SimSun","宋体"; font-size: 11pt; }p.ctl { font-family: "Times New Roman"; font-size: 11pt; }Environmentalimpact of agricultural pesticides, regulations on the production,transportation, use and the disposal of pesticides have increasedconsiderably on last years and it is therefore essential to developmethods of analysis allowing multiresidual determination at thelevels established by the legislation. Glyphosate (GLY) andglufosinate (GLU) are two of the more used herbicides, whileaminomethylphosphonic acid (AMPA) is the natural decompositionproduct usually monitored. Gas Chromatography coupled to massspectrometric detection (GC-MS) is an efficient, robust, fast andwidely recognized method to analyze volatile analytes. These featuresmakes GC-MS to be preferred over other analytical separation methodsif appropriate protocols are available. For the GC-MS analysis ofGLY, GLU and AMPA, derivatization is mandatory, not only because ofthe difficulties in detection but also because of their lowvolatility. The more widely used derivatization method involves theuse of a mixture with a fluorinated alcohol, such as trifluoroethanol(TFE), with a perfluorinated anhydride, such as trifluoroaceticanhydride (TFAA). The reaction requires high temperature and the useof silanized vials. In this work we tested comparatively the use ofother several fluorinated alcohols, such as1,1-dihydroperfluorobutanol, 1,1,1,3,3,3-Hexafluoro-2-propanoland trifluoroethanol with anhydride trifluoroacetic, the use ofpolyethylene (eppendorf) vials while assisting the reaction withmicrowave, under different conditions of power and times. Finally,aiming to improvingthe analytical performances, the use of alternative chromatographiccolumns have been compared to those currently used. The obtainedperformances under all conditions are critically discussed.