LaMotte MINI BOD5 TEST KIT M-B User Manual
Page 3
2.
Fill two 60 mL BOD bottles (2-2053) about half full with dilution water.
With an appropriately sized pipet or graduated cylinder dispense the
precalculated amount of the sample into each of the two 60 mL BOD
bottles. Fill each bottle with dilution water and insert stopper. Exclude all air
bubbles.
3.
Fill two more 60 mL BOD bottles (2-2053) with only dilution water. Insert
stoppers.
4.
Incubate one bottle containing diluted sample (Step 2) and one bottle
containing only dilution water (Step 3) at 20°C for 5 days. Ensure that the
area above the stopper contains distilled water. Check daily or use bottle
covers (not supplied) to prevent evaporation.
5.
Follow the instructions below to run a dissolved oxygen determination on
the remaining BOD bottle from Step 2. Record the initial dissolved oxygen
content as D
1
. Run another dissolved oxygen determination on the
remaining BOD bottle from Step 3. Record initial dissolved oxygen content
for control as C
1
.
DIS SOLVED OX Y GEN DE TER MI NA TION PRO CE DURE
Fix ing the Sam ple
A.
Add 8 drops of *Manganous Sulfate Solution (4167WT) and 8 drops of
*Alkaline Potassium Iodide Azide (7166WT) to the sample. Cap and
mix by inverting several times. A precipitate will form. Allow the
precipitate to settle below the shoulder of the bottle before proceeding.
B.
Use the 1g spoon (0697) to add one level measure of Sulfamic Acid
Powder (6286). Cap and gently shake until the reagent and the
precipitate have dissolved. A clear-yellow to brown-orange color will
develop, depending on the oxygen content of the sample. Following
this, contact between the water sample and the atmosphere will not
affect test result. Once the sample has been “fixed” in this manner, it is
not necessary to perform the actual test procedure immediately.
Test Pro ce dure
C.
Fill the test tube (0608) to the 20 mL line with the “fixed” sample.
Cap. If the color of the “fixed” sample is already a very faint yellow,
skip Step D.
D.
Fill the Direct Reading Titrator (0377) with the Sodium Thiosulfate
Solution, 0.025N (4169) in the manner described in the Titrator
manual. Insert the Titrator into the center hole of the test tube cap.
While gently shaking the tube, slowly press the plunger to titrate until
the yellow-brown color is reduced to a very faint yellow.
E.
Remove the titrator and cap. Be careful not to disturb the Titrator
plunger, as the titration begun in Step D will be continued in Step F.
Use the pipet (0392) to add 8 drops of Starch Indicator Solution
(4170). The sample should turn blue.