General Notes; Method Notes; Chemical Method Notes - Orbeco SC450 Manual Del Usuario

General notes

Method notes

• Prior to measurement ensure that the sample is suitable for analysis (no major interference)
and does not require any preparation i.e. pH adjustment, filtration etc.
• Reagents are designed for use in chemical analysis only and should be kept well out of
the reach of children.
• Ensure proper disposal of reagent solutions.
• Material Safety Data Sheets: available on request.
(Internet: www.orbeco.com)

Chemical method notes:

Method:
The sample is heated at 150
which is a strong oxidizing agent. Organic compounds in the sample are oxidized, reducing
the dichromate ion (Cr
In the Low Range (LR) Test (0-150 mg/L), the amount of remaining Cr
Mid Range (MR) (0-1,500 mg/L) or (HR) (0-15,000 mg/L), the amount of Cr
measured. The results are measured as the amount of oxygen (O
water sample. The LR and MR test is displayed in mg/L while the HR test shows g/L.
The COD reagent contains both mercury and silver—the mercury controls chloride
interferences and the silver functions as a catalyst to speed the reaction.
Application:
Samples can be measured if the chloride content does not exceed 1,000 mg/l (LR/MR) or
10,000 mg/l (HR).
In exceptional cases, compounds contained in the water cannot be adequately oxidized. This
results in low reading, compared with the reference method.
Different methods of sampling, preparation of the sample itself and the time elapsed between
taking the sample and analysis can all affect the obtained results.
SC450_V1_12/2010
C for two hours in the presence of potassium dichromate,
o
O ) to the green chromic ion (Cr
2–
2 7
).
3+
is measured; In the
6+
produced is
3+
) consumed per liter of
2
5