New agricultural technology needs to be adopted, encompassing a new high-yielding variety of seeds, pesticides, fertilizers, and manures. Residue analysis of pesticides, being an environmental and food quality parameter attracts a large number of human labor as well as resources worldwide (Kyriakos et al. (2014)). To ensure the environment and health protection in the present scenario, a large number of pesticides need to be monitored regularly (Sharma et al. (2010); Tankiewicz et al. (2011); Llorent-Martinez et al. (2011)). Dithiocarbamates (DTCs) are organosulfur molecules that have been used as pesticides in agriculture for several years. Zineb [Ethylene(bisdithiocarbamate)zinc(I)], an EBDTC pesticide (Fig. 1.) is widely used in agriculture and horticulture for pest control (prevent or kill pests) acting as a nitrogen stabilizer, desiccant, plant regulator and synergist as well as fungicide in the painted surface, leather, wood, and plastic surfaces (Amorello et al. (2013)).
It is generally used as a broad-spectrum fungicide for the control of foliage and fruit diseases of many vegetables, especially tomato, potato, and vine crops, and of flowers, trees, turf, and some fruit. The secondary effect of the use of zineb is to supply zinc to deficient plants. Concern about the environmental impact of extensive use of pesticides has prompted research into the environmental fate of these chemicals which is strongly influenced by their interaction with soil as the latter is the ultimate reservoir for these species irrespective of their application target. The pesticides are partitioned between the solution phase and the soil solids in the soil through adsorption. Pesticide adsorption by soil is a naturally occurring phenomenon that influences the extent of surface and groundwater contamination. The escalating use of pesticides has led to a serious and hazardous effect on the environment and on flora and fauna, which needs to be checked and controlled at trace amounts in underground and surface water. Several commonly used pesticides have genotoxic properties demonstrated by many studies (IARC (1991); IARC (1976); IARC (1986); IARC (1987)). Many instrumental methods have been designed and studied for the determination of dithiocarbamate fungicides involving, thin layer chromatography (TLC) (Muzhanovskii et al. (1982)), high-performance liquid chromatography (HPLC) (Irth et al. (1986); Gustafsson et al. (1983)), gas chromatography (GC) (Uno et al. (1982)) and polarography (Karageogiev et al. (1981); Halls et al. (1968)), etc. McLeod and McCully (McLeod et al. (1969)) used head-space chromatography to determine dithiocarbamate fungicides of CS2 evolved from foodstuffs in controlled conditions and similar analytical methods were also given (Committee for Analytical Methods (1981)). Based on Clark’s method (Clark et al. (1951)), few spectrophotometric methods involve the acidic decomposition of dithiocarbamates and can also be determined by methods other than acid decomposition including iodometry in anhydrous solvents (Grand et al. (1968); Clyde (1983)) indirect titration with EDTA (Hyman (1969)) and determining the metallic component of the pesticide (Quintero et al. (1991); Perez-Ruiz et al. (1996)). An alternative approach to metal analysis, derivative spectrophotometry involves the rate of change of absorbance with wavelength which is measured as a function of wavelength, showing good sensitivity and specificity (Sanchez Pojas et al. (1998)). The first derivative is a plot of spectral slope against wavelength where the peak height and amplitude measurements are proportional to the analyte concentration. Several other methods have been studied and reported for the detection and analysis of zineb such as capillary electrophoresis (Malik et al. (2000)), spectrophotometry (Malik et al. (2004); Kaur et al. (2011)), and voltammetry (Ulkhovich et al. (1983)). High-sensitivity analytical techniques are required to determine the zineb at trace levels.
In this view, we hereby report a relatively simple, rapid, sensitive, and selective spectrophotometric method for the determination and recovery of zineb by the formation of a zineb-chloranil complex in acetonitrile using acrylonitrile as extractant subsequently determined by spectrophotometry at 415 nm in apple, grains (wheat and rice), vegetable(cauliflower), water sample and various soil samples.