LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 56)

COD - LOW RANGE
MERCURY FREE DIGESTION • CODE 5-0072
MERCURY DIGESTION • CODE 5-0075
QUANTITY CONTENTS CODE
25 *COD Low Range Mercury Free Tubes
*5-0072
or 25 *COD Low Range Mercury Tubes
*5-0075
*WARNING: Reagent marked with a * are considered hazardous substances. Material
Safety Data Sheets (MSDS) are supplied for these reagents. For your safety read label
and accompanying MSDS before using.
COD Low Range Mercury Free Tubes are not USEPA approved.
COD Low Range Mercury Tubes are USEPA approved.
Equipment needed but not supplied:
1 COD Adapter
5-0087
1 COD Reactor, 8 vial, 110V
5-0069
or 1 COD Reactor, 8 vial, 220V
5-0070
or 1 COD Reactor, 25 vial, 110/220V
5-0094
1 Volumetric Pipet, 2.0 mL
2-2168
1 Pipet Bulb
2-2164
Chemical Oxygen Demand (COD) is a measure of the amount of organic
matter in water which is susceptible to oxidation by chemical oxidants. COD
can be empirically related to the Biological Oxygen Demand (BOD) and
organic carbon content of a specific source of water. This correlation must be
determined experimentally for each source of water.
APPLICATION:
Domestic and industrial wastes.
RANGE: 5 - 150 mg/L COD
METHOD: Dichromate in the presence of silver salts, at high
temperature in a closed system, oxidizes most organic
compounds to 95-100% of the theoretical amount. This
process is called digestion. As dichromate oxidizes the
organic compounds, the amount of yellow color is reduced.
The remaining yellow color is measured colorimetrically at
the 420 nm and is directly proportional to the COD of the
sample.
SAMPLE
HANDLING &
PRESERVATION: Collect samples in glass and test as soon as possible. If
samples must be stored, preservation is accomplished by the
addition of concentrated H
2
SO
4
to adjust the pH below 2.
Samples with suspended solids should be homogenized in a
blender (100 mL for 30 seconds) and then stirred gently with
a magnetic stirrer.
COD PLUS TEST PROCEDURES 6/03 COD - LOW RANGE 1/4