Hanna Instruments HI 93754B User Manual

Instruction Manual

HI 93754A-25 LR
HI 93754B-25 MR
HI 93754C-25 HR

COD

Chemical Oxygen Demand

Reagents

www.hannainst.com

Dear Customer,
Thank you for choosing a Hanna product. Please read this
instruction manual carefully before using the reagent. This
manual will provide you with the necessary information for the
correct use of the reagents. If you need additional information,
do not hesitate to mail us at [e-mail].

PRELIMINARY EXAMINATION

Remove the product from the packing material and examine
it carefully to make sure that no damage has occurred during
shipment. If there is any damage, notify your Dealer.
Each kit is supplied complete with:

•COD test tubes (25 pcs);

•2 graduated syringes (1 ml) with tip;

•Instruction Manual.
Note: save all packing material: any defective item must be
returned in its original packing with the supplied accessories.

GENERAL DESCRIPTION

Three reagent kits are available, according to different COD
ranges:

•HI 93754A-25 LR: COD Low Range (0 to 150 mg/L)
Vial cap color: RED.

•HI 93754B-25 MR: COD Medium Range (0 to 1500 mg/L)
Vial cap color: WHITE.

•HI 93754C-25 HR: COD High Range (0 to 15000 mg/L)
Vial cap color: GREEN.

Each kit contains 25 ready-to-use vials with premeasured
reagents: just add sample to the vial and tightly cap it before
digestion. Different range vials may be easily distinguished by
mean of the cap color.

METHOD

Adaptation of the EPA 410.4 approved method. This method
covers the determination of COD in surface water, domestic
and industrial wastes.
The sample is digested in the presence of dichromate at 150°C
for 2 hours. Oxidizable organic compounds reduce the
dichromate (orange) ion to the chromic (green) ion.

INSTRUCTIONS

Before starting to use these reagent kits it is
important to read carefully this manual and the

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

1 - Samples containing settleable solids need to be

homogenized with a blender.

2 - For sample digestion use a block heater reactor with holes

to accommodate digestion vials. Use of the optional safety
shield is strongly recommended.
Preheat the reactor to 150 °C (302°F). For correct use of
the reactor follow Reactor Instruction Manual*.
Do not use an oven or microwave because leaking samples
can generate a corrosive and possibly explosive
atmosphere.

3 - Remove the cap from a reagent vial for the required COD

range.
Note: the reagent is light sensitive, thus store the unused
vials in their container and in a refrigerator if possible.

4 - Use the supplied syringe and add 2 ml (for LR and MR

test) or 0.2 ml (for HR test) of sample to the vial, while
keeping the vial at a 45-degree angle.
This is the sample.

Range Reagent Vial cap Sample

code color q.ty

0-150 mg/L HI 93754A-25 red 2.0 mL
0-1500 mg/L HI 93754B-25 white 2.0 mL
0-15000 mg/L HI 93754C-25 green 0.2 mL

Note: to measure exactly 0.2 mL of sample with the syringe,
push the plunger completely into the syringe and insert
the tip into sample. Pull the plunger out until the lower
edge of the seal is on the 0.0 mL mark of the syringe.
Insert the syringe into the vial and push the sample out
until the lower edge of the seal is on the 0.2 mL mark.

5 - Replace the cap tightly and mix by

inverting the vial a couple of times.
Warning: as the vial becomes very
hot during mixing, be careful in
handling it.

6 - Using the other clean syringe, add to another reagent vial

deionized water repeating steps 4 and 5 (2 ml for LR and
MR, and 0.2 ml for HR). This is the blank.
Note: for an accurate measurement, run a blank with each
set of samples and use the same box of reagents for blank
and samples.

7 - Insert the vials into the

reactor* and heat them for
2 hours at 150°C.

8 - At the end of the digestion period,

turn the reactor off (if you are using
the Hanna Reactor, it will
automatically switch off). Wait for
twenty minutes to allow the vials to
cool to about 120°C.

9 - Invert each vial several times while still warm, then place

them in the HI 740216 rack.
Warning: as the vials are still hot, be careful in handling
them.

10 - Leave the vials in the tube rack to cool to room

temperature. Do not shake or invert them anymore
otherwise the samples may become turbid.

11 - For colorimetric determination of COD, follow the

procedure described in the Photometer Instruction
Manual*.

* Note: for best results in readings use the Hanna equipment:

C9800 Reactor and C99 or C214 Photometers.

INTERFERENCES:

chlorides LR >2000 mg/L (ppm)

MR >2000 mg/L (ppm)
HR >20000 mg/L (ppm)

Samples with higher chloride concentration should be diluted.

HEALTH & SAFETY
SSAFETY

The chemicals contained in these kits may be
hazardous if improperly handled. Read the
Health & Safety Data Sheet before performing
tests.

Safety equipment: Wear suitable eye protection and clothing,
and follow instructions carefully.
Reagent spills: If reagent spillage occurs, wipe up immediately
and rinse with plenty of water.
If reagent contacts skin, rinse the affected area thoroughly
with water. Avoid breathing released vapors.
Reagent vial disposal: Reagents contain different waste
pollutants. After use dispose of the reagent vials according to
the local regulations.

ACCESSORIES

C 9800-01 Hanna Reactor (115 VAC)
C 9800-02 Hanna Reactor (230 VAC)
C 99 Hanna Photometer (for Laboratories)
C214 Hanna Photometer (for Wastewater

HI 740142 1 mL graduated syringe
HI 740143 1 mL graduated syringe (6 pcs)
HI 740216 Test tube cooling rack (25 holes)
HI 740217 Laboratory bench safety shield

SSAFETY

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SISTRCODR3 01/03