Jv. Sancho et al., RAPID-DETERMINATION OF GLYPHOSATE RESIDUES AND ITS MAIN METABOLITE AMPA IN SOIL SAMPLES BY LIQUID-CHROMATOGRAPHY, International journal of environmental analytical chemistry, 62(1), 1996, pp. 53-63
Efficient procedures for the trace-level determination of glyphosate a
nd/or the metabolite AMPA in various type of soil samples has been dev
eloped. After extraction in alkaline media an aliquout of the extract
is neutralized prior to a precolumn derivatisation step with FMOC-Cl y
ielding highly fluorescent derivatives of the analytes. Two different
LC-methods have been applied. The first one is focussed at the determi
nation of glyphosate only and requires a liquid-liquid extraction step
with ethyl acetate for the removal of the reagent excess prior to the
RPLC-analyses performed on a single 25 cm C18 column under isocratic
elution conditions. The second method makes use of coupled-column LC f
or on-line sample cleanup of diluted extracts and allows the determina
tion of both glyphosate and AMPA. With the developed procedures glypho
sate and AMPA were succesfully recovered from different kind of soils
at 400 and 40 ng g(-1) fortification levels. Sample throughput is at l
east 20 samples per day. Depending on the type of soil, viz. high or l
ow clay content and organic matter, and the LC method used, limits of
determination range between 100 and 10 ng . g(-1) for both analytes.