Determination of Pentachlorophenol in Environmental Samples by Spectrophotometry

Pentachlorophenol (PCP) (2,3,4,5,6- pentachlorophenol) is an organochlorine compound used as a pesticide and a disinfectant. PCP is used as a herbicide, insecticide, fungicide and disinfectant. Some applications include agricultural seeds (for nonfood uses), leather, masonry, wood preservation, cooling tower water, rope, and paper mills. Determination of Pentachlorophenol was based on the reaction of PCP with concentrated nitric acid followed by potassium iodide for the liberation of iodine. Liberated iodine reacted with leuco malachite green for the formation of green colour dye which was measured at 610 nm against a reagent blank. Parameters affecting the reaction were studied. The interfering effect of various species was also investigated and the methods were applied on some vegetables and fruit samples.

A Rapid and Accurate Non Extractive Procedure For Analyzing Monocrotophos In Environmental Samples By Spectrophotometry

An organophosphorous insecticide monocrotophos is increasingly being utilized in agriculture to control insects on a broad range of crops. In this study a new reaction system using spectrophotometric method for quantitative determination of monocrotophos is proposed. The method is based on the bromination of monocrotophos to form dibromomonocrotophos which react with Potassium iodide-Potassium iodate mixture in the presence of leuco malachite green (LMG) to form a water soluble greenish blue colored complex. The change in absorbance as a criterion of the bromination reaction progress was followed spectrophotometrically. To obtain t he maximum sensitivity the effective reaction variables were optimized. The absorbance maximum was observed at 620 nm. Under optimized experimental conditions calibration graph was linear over the range of 10.0-60.0 µg. The molar absorptivity of the colored system is 3.66×104 L mol-1 cm-1 and sandell’s sensitivity is 0.25×10-2 µg cm-2. The calculated detection limit was 0.44 µg mL-1. The interfering effect of various species was also investigated. The present method was successfully applied to the analysis of monocrotophos in different environmental and water samples.