SIMULTANEOUS DETERMINATION OF CHLOROTHALONIL AND HEXACHLOROBENZENE INTECHNICAL AND FORMULATED MATERIALS BY CAPILLARY GAS-CHROMATOGRAPHY

A capillary gas chromatographic method using flame ionization detectio n was developed for simultaneous assay of chlorothalonil and hexachlor obenzene in technical material and formulated products. Method precisi on is excellent, and the method allows simultaneous determination of o ne chemical impurity. The method uses an internal normalization reagen t (n-butyl phthalate). Modification and extension of the method to for mulated products, including wettable powders, water-based flowables, a nd dispersible (or dry flowable) granular formulations, are discussed. Preliminary statistical analysis of intra- and interlaboratory compar isons was performed to evaluate method ruggedness. Average relative st andard deviations for technical materials were 0.34 and 0.17% from 2 l aboratories. Additional method validation studies were conducted to ex amine the influence of pH, solvent systems, gas chromatographic system s, and temperature conditions on different formulations.