抄録
A paraquat-sensitive electrode was constructed by use of a poly (vinyl chloride)-based membrane containing sodium tetrakis [3, 5-bis (trifluoromethyl) phenyl] borate as an ion exchanger and 2-fluoro-2'-nitrodiphenyl ether as a membrane solvent. The minimum detection limit of paraquat was 5×10-7M. The calibration slope of the electrode in linear region was 28 mV/decade. The selectivity coefficients against Na+, K+, Mg2+ and Ca2+ were less than 10-4, and substantially, these inorganic ions did not interfere with the response to paraquat. This electrode was utilized for a criminal investigation. Paraquat added intentionally to drinks such as juice, cola and milk in cases of murder can speedily be measured by the paraquat-sensitive electrode without separating the herbicide from assay mixtures. By using the present electrode, we could estimate paraquat down to 5×10-5M contained in juice. This sensitivity was sufficient enough for the detection of paraquat used in a crime : when the lethal dose of paraquat (2.4 g/a man of 60 kg) was mixed with juice (250 ml), the concentration became about 40 mM. The electrode was also applied to a clinical analysis, and paraquat in the serum could successfully be detected down to 2μM.
