大气降水中H_2O_2的测定方法

DETERMINATION METHOD OF H2O2 IN ATMOSPHERIC PRECIPITATION

本文改进和发展了一种能测定大气降水中的微量H_2O_2的分光光度法。该法采用酶催化反应,有较好的选择性和较高的灵敏度。将原缓冲体系HAc-NaAc改为KHP后,克服了HAc-NaAc体系的缺点并大大简化了测定步骤。由工作曲线计算所得的摩尔吸收系数为7.4×10~4L/(cm·mol),最低可测浓度为0.3μmol/l.Mn^(2+)对测定有轻度干扰,有机氢过氧化物和NO_(2-)有较严重的干扰,但这些物质在降水中的浓度很低,总于挑一般小于5％,且通过加入过氧化氢酶的办法可以排除。对照结果表明,本法与国际公认的POPHA荧光法有很好的可比性。

A spectrophotometric method to determine trace H2O2 in precipitation was improved and developed,The method has good selectivity and sensitivity because of applying an enzymatic catalysis reaction.The exivting defects in HAc-NaAc buffer solution were eliminated and the procedure was simplified by changing the buffer solution from HAc-NaAc to KHP.The absorptivity based on H2O2 and calculated from the calibration curve is 7.4×104 L/(cm·mol)and the lowest measurable concentration is 0.3Hmol/L.The measurement is interfered slightly by Mn2+and seriously by NO2-and organic hydroperoxides.Because of very low cocentrations of these substances in precipitation,the total interference is usually smaller than 5 % and may be deducted by adding catalase.The results of comparison showed that there was good comparability between this spectrophotometric method and the well-known POPHA fluorescent method.