ゴム製品中の2-Mercaptobenzimidazole系老化防止剤の分析

抄録

A method for the determination of 2-mercaptobenzimidazole (MBI) type antioxidants in rubber products by HPLC was developed. The analytical conditions to separate 2-mercapto-4-methylbenzimidazole (4MMBI) from 2-mercapto-5-methylbenzimidazole (5MMBI) by HPLC and to extract MBI type antioxidants from rubber products were examined in detail. The recommended method was as follows. MBI type antioxidants was extracted with methanol five times. The evaporation residue of the extract was dissolved in water and injected to HPLC. The HPLC conditions were as follows : column, CAPCELL PAK C18 (4.6 i. d.×250mm) ; column temperature, 40°C ; mobile phase, 0.1 M phosphate buffer (pH 6.5)-acetonitrile (87 : 13) ; flow rate, 1.0ml/min ; detection wavelength, 304nm (MBI, 4MMBI) and 307 nm (5MMBI). This method was applied to determine MBI type antioxidants in 12 commercial rubber boots. Consequently, 11.5-67.7 μg/g of MBI was detected in 4 samples, but 4MMBI and 5MMBI were not detected in any samples.