Lovibond Maxi Direct, Инструкция по эксплуатации, Страница: 71 / 268

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MaxiDirect_2c 03/2010
1.1 Methods
Notes:
1. This colour scale was originally developed by A. Hazen as a visual comparison scale.
It is therefore necessary to ascertain whether the extinction maximum of the water
sample is in the range from 420 to 470 nm, as this method is only suitable for water
samples with yellowish to yellowish-brown coloration. Where applicable, a decision
should be made based on visual inspection of the water sample.
2. This method 204 – Hazen – is calibrated on the basis of the standards specified by
”Standard Methods for the Examination of Water and Wastewater” (also see EN ISO
7887:1994).
1 Pt-Co colour unit = 1 mg/L of platinum as chloroplatinate ion
3. The estimated detection limit is 15 mg/L Pt.
4. Colour may be expressed as “apparent” or “true” colour. The apparent colour is defined
as the colour of a solution due to dissolved substances and suspended particles in the
sample. This manual describes the determination of true colour by filtration of the water
sample. To determine the apparent colour, non-filtrated deionised water and sample are
measured.
5. Sample collection, preservation and storage:
Pour the water sample into clean glass or plastic containers and analyse as soon as
possible after the sample is taken. If this is not possible, fill the container right up to the
top and seal tightly. Do not stir the sample; avoid lengthy contact with the air.
The sample may be stored in a dark place at a temperature of 4°C for 24 hours. Before
performing measurements, the water sample must be brought up to room temperature.