J. Nolte et R. Kruger, Direct methylation at the surface of Carbopack B - Part II: Determination of phenoxyalkanoic acid herbicides, FRESEN J AN, 365(7), 1999, pp. 610-614
The determination of phenoxyalkanoic acids in different types of water with
in the limits of the European drinking water guideline is described. Most o
f these acids are used world-wide as herbicides and growth regulators. Comp
ounds having an acidic hydrogen in their structure are very strongly adsorb
ed on Carbopack B, a special graphitized carbon black. This effect was used
for the transformation of analytes to methyl esters directly on the surfac
e of the adsorbent, using trimethylsulfonium hydroxide (TMSH) as derivatiza
tion reagent. After elution with ethyl acetate the derivatives were identif
ied and quantified by gas chromatography/mass spectrometry (GC/MS). The int
eraction between analyte and adsorbent and the yields of the derivatization
step are influenced by the length of the alkanoic chain.