【摘要】 本文介绍了用微型计算机控制柱塞滴定器,以电流滴定法检测终点的海水溶解氧的自动滴定法;给出了仪器结构框图和计算机程序框图;讨论了方法的的不确定度,并与淀粉终点检测法和比色终点检测法等进行了比较。本方法操作简便,测定的标准偏差为0.30μmol/L,单个样品分析只需3min。更多还原

【Abstract】 The Winkler Method for dissolved oxygen analysis has been automated by using a "PET" microcomputer controlled METROHM E-535 piston buret coupled with amperometric end point detection. The automated method is easy in operation and has a shipboard standard deviation of 0.30μmol/L, short in analysis time 3 min per sampleIn comparison with the starch’s method, the automatic method is higher in both sensitivity and precision. For Seawater the starch end-point was at 7 mV and the range of end-point between the two methods was 3.6μl. For tap water, standard and blank they are 10mV and 5μl. So there will be 0.25μmol/L of Systemetic error when starch detection is used in analysis of seawater.This method, applicable to the measurement of estuarine water with suspended particles, has no problems due to degassing and bubble formation when the picked samples are warming up. The reasones of precision improvement of amperometric titration method are disscussed too.更多还原