Pasha Chand, Narayana Badiadka
Department of Chemistry, P. A. College of Engineering, Mangalore 574153, India.
Bull Environ Contam Toxicol. 2008 Jan;80(1):85-9. doi: 10.1007/s00128-007-9321-5. Epub 2007 Dec 6.
A simple, selective and sensitive spectrophotometric method is proposed for the determination of widely used organochlorine pesticide endosulfan using thionin and methylene blue as chromogenic reagents. The method is based on the liberation of sulfur dioxide from endosulfan by adding acid reagent and alcoholic potassium hydroxide. The liberated sulfur dioxide is passed through potassium iodate solution and the iodine so liberated bleaches the violet color of thionin and blue color of methylene blue and is measured at 600 nm and 665 nm respectively. This decrease in absorbance is directly proportional to the endosulfan concentration. The Beer's law is obeyed in the range of 0.4-7.0 and 0.2-9.0 microg mL(-1) of endosulfan using thionin and methylene blue as reagents respectively. The molar absorptivity and Sandell's sensitivity were found to be 1.05 x 10(5) and 5.03 x 10(4) L mol(-1) cm(-1), 3.85 x 10(-3) and 8.10 x 10(-3) microg cm(-2) of endosulfan using thionin and methylene blue as reagents respectively. The method has been applied for the determination of endosulfan in water, soil and vegetables.
提出了一种简单、选择性好且灵敏的分光光度法，用于测定广泛使用的有机氯农药硫丹，该方法使用硫堇和亚甲基蓝作为显色剂。该方法基于通过加入酸性试剂和乙醇氢氧化钾从硫丹中释放出二氧化硫。释放出的二氧化硫通过碘酸钾溶液，释放出的碘使硫堇的紫色和亚甲基蓝的蓝色褪色，分别在600 nm和665 nm处进行测量。吸光度的这种降低与硫丹浓度成正比。分别使用硫堇和亚甲基蓝作为试剂时，硫丹在0.4 - 7.0和0.2 - 9.0 μg mL(-1)范围内符合比尔定律。使用硫堇和亚甲基蓝作为试剂时，硫丹的摩尔吸光系数和桑德尔灵敏度分别为1.05×10(5)和5.03×10(4) L mol(-1) cm(-1)、3.85×10(-3)和8.10×10(-3) μg cm(-2)。该方法已应用于水、土壤和蔬菜中硫丹的测定。
