DETERMINATION OF ACTIVE COMPONENTS IN INSECTICIDE FORMULATIONS BY LIQUID-CHROMATOGRAPHY AND RESOLUTION OF OVERLAPPED PEAKS BY MULTIVARIATE-ANALYSIS AND DERIVATIVE SPECTROPHOTOMETRY
Jaj. Garcia et al., DETERMINATION OF ACTIVE COMPONENTS IN INSECTICIDE FORMULATIONS BY LIQUID-CHROMATOGRAPHY AND RESOLUTION OF OVERLAPPED PEAKS BY MULTIVARIATE-ANALYSIS AND DERIVATIVE SPECTROPHOTOMETRY, Analytica chimica acta, 321(2-3), 1996, pp. 273-278
In liquid chromatography, complex mixtures of pesticides may show peak
s with a great overlap under the experimental conditions commonly used
. The use of partial-least squares (PLS) regression and derivative spe
ctrophotometry makes it possible to discriminate between the spectral
bands of the overlapping chromatographic solutes, taken from peaks wit
h co-eluting species. In this paper, a procedure for the determination
of insecticides in commercial formulations by using a diode-array spe
ctrophotometer as chromatographic detector has been devised. The proce
dure consists of two steps. In the (first) chromatographic step, the a
ctive component peak (corresponding to fenitrothion or permethrin) whi
ch is isolated in time is determined by conventional liquid chromatogr
aphy; the appropriate conditions permit to remove also the interferenc
e from solvents in the commercial formulations. In the (second) multiv
ariate step, partial-least squares regression is applied to the overla
pped spectra of the co-eluting components (piperonyl butoxide-neopynam
ine or dicofol-tetradifon). This method makes it possible to analyze c
ompounds showing appreciable overlap of their chromatographic peaks, w
ithout modification of the experimental variables used.