The interinstrument variability of an assortment of six bench-top and four portable turbidimeters
was evaluated using four calibration materials, including user-prepared formazin, commercial
formazin, commercial stabilized formazin, and commercial suspensions of polystyrene latex
microspheres. The calibration method/material, the type of light source, and the use of an
instrument's ratio-measurement feature did not have a significant effect on agreement
among the instruments. However, the results divided the instruments into two groups. The
instruments in group A are those that do not automatically set a predetermined reading
when a sample of low-particle (dilution) water is put in the instrument during the calibration
procedure. The instruments in group B use the calibration procedure to automatically set the
low-particle reading at either zero or 0.02 ntu. Both groups include portable-type instruments
and 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 about
0.1-0.3 ntu higher than those for group B.
Includes 22 references, tables, figures.
| Edition : | Vol. 96 - No. 8 |
| File Size : | 1
file
, 1.4 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 08/01/2004 |
