Environmental Express 99561-84, Instruction Manual

Page: 24 / 40

COD 200 Instruction Manual 24
COD MR / 20 - 1500 mg/l / MR
Sampling
1. In the standard version, chloride interferes from a concentration of 1000 mg/L. In the
mercury-free version, the disturbance depends on the chloride concentration and the
COD. Concentrations from 100 mg/L chloride can lead to significant disturbances
here. See "Sample Preparation" Section for notes on removing chloride interfernce.
2. Suspended solids in the vial can lead to incorrect measurements and so to avoid
this, it is important to place the vials carefully in the sample chamber as the method
necessitates a build-up of precipitate at the bottom of the vial.
3. The outer walls of the vial must be clean and dry before the analysis is carried out.
Fingerprints or water droplets on the vial lead to incorrect measurements.
Notes About Method
1. The blank is stable when stored in the dark.
2. Blanks and test vials must be from the same batch.
3. Do not place hot vials in the sample chamber. The most stable measured values can
be determined if the vials are left standing overnight.