Liquid chromatography/mass spectrometry acidic herbicides

A method that uses high performance liquid chromatography/ mass spectrometry (HPLC/MS) for the analysis of chlorinated phenoxyacid herbicides is described. During method development different techniques were used to increase both the sensitivity and the specificity of thermospray HPLC/MS for chlorinated acid herbicides. These included the operation of the instrument in the negative chemical ionization (NCI) mode initiated by discharge and the use of a wire-repeller in the ion source for efficient extraction of positive ions. Single quadrupole repeller-induced and multiple quadrupole collision activated dissociation (CAD) experiments were also performed to increase the structural information of the mass spectra. 

Catalina, M. I., Dalliige, J., Vreuls, R. J. J., and Brinkman, U. A. Th., Determination of chlorophenoxy acid herbicides in water by in situ esterihcation followed by in-vial liquid-liquid extraction combined with large-volume on-column injection and gas chromatography-mass spectrometry, J. Chromatogr. A, 877, 153-166, 2000. 

Chiron S, Papilloud S, Haerdi W, Barcelo D (1995) Automated online liquid-solid extraction followed by liquid chromatography-high-flow pneumatically assisted electrospray mass-spectrometry for the determination of acidic herbicides in environmental waters. Anal Chem 67(9) 1637-1643... 

Analysis of pesticides in water was performed by fully automated online solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/ MS) [25, 31]. These pesticides (a total of 22 belonging to the classes of triazines, OP, chloroacetanilides, phenylureas, thiocarbamates, acid herbicides, and anilides) were selected on the basis of previously published studies [20, 25], information gathered from the water authorities, and known use in rice crops. 

Di Corcia and Marchetti [160] determined chlorinated phenoxy acid and ester type herbicides in amounts down to lmg kg-1 or lower in soil by liquid chromatography combined with particle beam mass spectrometry and ultraviolet absorption spectrometry. 

Chlorinated [407,408] and 2,4-dinitrophenoxy acid herbicides [409] have been determined. liquid chromatography particle beam mass spectrometry has been used as an analytical finish [408]. Crescenzi et al. [410] evaluated the feasibility of selectively and rapidly extracting herbicide residues in soils by hot water and collecting analytes with a Carbograph 4 solid-phase extraction cartridge set on-line with the extraction cell. Phenoxy acid herbicides and those non-acidic and acidic herbicides that are often used in combination with phenoxy acids were selected for this study. Five soil samples were... 

Pozo, O., E. Pitarch, J.V. Sancho, and F. Hernandez (2001). Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography-electrospray tandem mass spectrometry. J. Chromatogr. A, 923 75-85. 

Vreeken, R.J., P. Speksnijder, I. Bobeldijk-Pastorova, et al. 1998. Selective analysis of the herbicides gly-phosate and aminomethylphosphonic acid in water by on-line solid-phase extraction-high-performance liquid chromatography-electrospray ionization mass spectrometry. J. Chromatogr. A 794 187-199. 

Kim, I.S., F.I. Sasins, R.D. Stephens, J. Wang, and M.A. Brown. 1991. Determination of chlorinated phenoxy acid and ester herbicides in soil and water by liquid chromatography particle beam mass spectrometry and ultraviolet spectrophotometry. Anal. Chem. 63 819-823. 

Takino, M., Daishima, S., and Nakahara, T., Automated online in-tube solid-phase microextraction followed hy liquid chromatography/electrospray ionization-mass spectrometry for the determination of chlorinated phenoxy acid herbicides in environmental water. Analyst, 126, 602-608,... 

---