Analytical quality parameters of high performance liquid chromatography with diode-array detection method for multiresidue determination of pesticides.

A study was done to establish the linearity, analytical sensitivity, limit of detection, limit of identification and precision of a method for the sim ultaneous detrmination of thirteen pesticides belonging to different chemic al classes: methyl-carbamates, triazines, urea-derived herbicides and insec ticides, a carbamoyl oxime, EI phtalimide, an acyl alanine, an organophosph orus insecticide and a uracil-derived compound, all of them potential pollu tants of natural waters and soils. The analytes were separated on a C-18 60 Angstrom, 4 mu m (3,9 mm id x 300 mm) column with an acetonitrile-water ba sed gradient elution program. To this end statistical model of linear regre ssion was used. Limits of detection determined by three different methods w ere compared. A linear relationship for all compounds was obtained at the c oncentration levels under study (between 0.030 and 0.120 ng mu L-1 for carb aryl and between 1,5 and 6,0 ng mu L-1 for captan). Analytical sensitivity ranged between 0,011 and 2,611 ng and limits of detection were in the range 0.04-9.2 ng. Spectral parameters used for identity and purity tests allowe d to establish the limits of identification, ranging from 0.15 and 7.5 ng. The developed method would allow a wider number of pesticides to be added f or their determination in waters, due to its ability to separate the analyt es and its capacity for peak identification and quantification at very low concentration levels.