Full Description

The interinstrument variability of an assortment of six bench-top and four portable turbidimeterswas evaluated using four calibration materials, including user-prepared formazin, commercialformazin, commercial stabilized formazin, and commercial suspensions of polystyrene latexmicrospheres. The calibration method/material, the type of light source, and the use of aninstrument's ratio-measurement feature did not have a significant effect on agreementamong the instruments. However, the results divided the instruments into two groups. Theinstruments in group A are those that do not automatically set a predetermined readingwhen a sample of low-particle (dilution) water is put in the instrument during the calibrationprocedure. The instruments in group B use the calibration procedure to automatically set thelow-particle reading at either zero or 0.02 ntu. Both groups include portable-type instrumentsand different types of light sources. Over a turbidity range of approximately 0.01-0.5 ntu(measured by the group A instruments), the mean readings for group A instruments were about0.1-0.3 ntu higher than those for group B. Includes 22 references, tables, figures.

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Edition: Vol. 96 - No. 8 Published: 08/01/2004 Number of Pages: 13 File Size: 1 file , 1.4 MB