Hanna Instruments HI 83099 User Manual

Page 49

OXYGEN DEMAND, CHEMICAL MEDIUM RANGE

SPECIFICATIONS

Range

0 to 1500 mg/L COD

Resolution

1 mg/L

Accuracy

±15 mg/L or ±4 % of reading @ 25 °C, whichever is greater

Typical EMC

±1 mg/L

Deviation
Light Source

Tungsten lamp with narrow band interference filter @ 610 nm

Method

Adaptation of the USEPA 410.4 approved method for the COD determination on
surface waters and wastewaters. Oxidizable organic compounds reduce the dichromate
ion (orange) to the chromic ion (green). The amount of chromic ion formed is
determined.

REQUIRED REAGENTS

Description

Q.ty/test

Q.ty/set

Reagent Vial

1 vial

25 vials

Deionized Water

2.0 mL

optional

Note: Store the unused vials in their container in a cool and dark place.

REAGENT SET

HI 93754B-25 Reagents for up to 25 tests

REQUIRED ACCESSORIES

HI 839800-01 Hanna reactor (115 VAC)
HI 839800-02 Hanna reactor (230 VAC)
HI 740216

Test tube cooling rack (25 holes)

HI 740217

Laboratory bench safety shield

For other accessories see page 132.

MEASUREMENT PROCEDURE

Before using the reagent kit carefully read all the instructions and the Manual Safety Data

Sheet (MSDS). Pay particular attention to all warnings, cautions and notes. Failure to do so
may result in serious injury to the operator.

Reagent Blank Correction: This method requires a reagent blank correction. A single blank vial may be used
more than once. The blank vial is stable for several months (room temperature). For most accurate measurement,
run a blank for each set of measurements and always use the same lot of reagents for blank and samples.

• Select the

Oxygen Demand, Chemical

HR (COD) method following one of the
procedures described in the

Method

Selection section (see page 12).

• Place the COD vial adapter in the

cuvet holder and ensure that the
adapter is well fit inside.

• Place the blank vial into the holder and push it completely down.

• Press the Zero key and the instrument will perform a zero sequence. If the zero sequence was

successfully done, the display will show “

-0.0-”. Now the meter is zeroed and ready for measurement.

• Remove the blank vial.

• Place the sample vial into the holder and push it completely down.

• Press

Read and the instrument will perform the reading.

• The instrument directly displays concentration in

mg/L of oxygen demand.

INTERFERENCES

Interference may be caused by:
Chloride (Cl¯) above 20000 mg/L.
Samples with higher chloride concentration should be diluted.