We report improved separation of the highly toxic contact herbicides paraquat, diquat, difenzoquat, mepiquat, and chloromequat by HPTLC. Quantification was based on a new derivatization reaction using sodium tetraphenylborate. Measurements were in the wavelength range from 440 to 480 nm or from 440 to 590 nm. An LED emitting very intense light at 365 nm was used for excitation. The quantification limits of paraquat and diquat in water, using improved solid-phase extraction, was in the low ng L
range. The linear range covered more than two orders of magnitude. Recovery was investigated for all the compounds, and was insufficient, ranging from 11 to 92%, but the method is inexpensive, rapid, and works reliably.
, in: J. Harvey, Jr., G. Zweig (eds.) Pesticide Analytical Methodology, 1980, 127–157.
M. Careri, L. Elviri, A. Mangia, I. Zagnoni
, Rapid. Commun. Mass. Spectrom.
Zagnoni I., '' (2002) 16Rapid. Commun. Mass. Spectrom.: 1821-1826.