Hach-Lange DR 5000 drinking water analysis, supplementary software LZV571 - Manual (Page 14)

14
Working procedures
2.4 Colour
Principle
The parameter "colour” can be determined from a sample by
measuring the intrinsic absorbance, that is without using reagents.
The spectral absorbance coefficients are determined in m
-1 (Colour
method) or in units based on a PtCo standard (Colour (PtCo)
method).
The colour of most yellow-brown natural waters and the outflows of
municipal sewage treatment plants can usually be measured at
436 nm. The colour of yellow-brown water can be measured by
comparison with suitable PtCo standards.
Range of application
Drinking water, surface water, wastewater
Measuring range
0–50 units (Colour (Pt/Co) method)
0–20 m
-1 (Colour method)
Accessories
• Spectrophotometer (436 nm)
• 50 mm rectangular cuvette (OS)
Interferences
Undissolved substances (turbidities) may cause high-bias results to
be obtained. This interference can be eliminated by membrane
filtration (pore size 0.45 µm).
Literature
DIN 38404 Part 1 (C1)
2.4.1 Procedure Colour
1. Select Stored Programs in the "Main Menu". Select test
number 904 and the required method (904 Colour or
904 Colour (PtCo)).
2. Insert the zero cuvette (distilled water) in the cell compartment.
Close the cell compartment. Touch Zero.
3. Insert the sample cuvette containing the first sample in the cell
compartment and close the cell compartment. Touch Read.
The result is displayed