低浊水的浊度测定问题

该文首先介绍了浊度仪的构造设计原理、浊度仪的光源波长、光检测器的响应波长、水中悬浮颗粒特性、布朗运动、杂散光及测定人员的操作对浊度测定的影响。用统计方法对不同型号浊度仪测定结果进行评价的结果认为:按ISO方法7027的光源波长为860 nm的浊度仪测定的浊度值当浊度低于0.5 NTU时,较其他各型浊度仪显著偏低。文章提出不同浊度仪测得的浊度的平均值X_T与相对标准偏差RSD_T有显著的相关关系,而与相对误差RE_T有相关关系但不够显著。对于低浊度水的测定数值最多只能保留到小数点后两位。FT660sc型激光浊度仪与HACH公司其他型号实验室用及在线浊度仪的初步测定比较,前者的准确度及精密度都较差,应对该型仪器用于低浊水的测定做进一步的研究。

Turbidity Measurement for Drinking Water with Low Turbidity

The influence of the design principles of the turbidimeter, the wave length of the light sources and the wave length of the response of the light detectors, the property of the suspended particulates in water, the Brownian disffusion, the stray light and the experience of the operators on the results of turbidity determination were introduced first. The results obtained by turbidimeters designed according to regulation of ISO method 7 027 give a lower turbidity values during the turbidity of the water samples below 0.5 NTU. The average values of turbidity obtained by different turbidimeters are correleted with the relative standard deviations and the co-relationship exists with the relative errors but more or less insignificant. As measurement of low turbidity of water, the figures obtained should be rounded off to keep 2 figures after the decimal point at most. The results of a preliminary comparaisian of the data obtained by determination of turbidity of spiked water samples with turbidimeters of models of FT660sc and laboratory turbidimeters and other process turbidimeters, indicate that the results obtained by turbidimeter FT660sc with laser light source hkely give a lower accuracy and lower precision and more works must be done on the application of this type turbidimrter for low turbidity determination.