Lamotte DISSOLVED OXYGEN TEST KIT User Manual download pdf (Page 4)

TITRATION

1. Fill the test tube (0608) to the 20 mL line with the “fixed” sample

and cap.

NOTE: For more precise oxygen measurements, fill graduated

cylinder (2-2297) to 20 mL line with sample. Transfer to test tube

(0608). Cap.

2. Fill the Direct Reading Titrator (0377) with *Sodium Thiosulfate,

0.025N (4169).

3. 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.

NOTE: If the color of the “fixed” sample is already a very faint

yellow, skip to Step 4.

4. Remove the Titrator and cap. Be careful not to disturb the Titrator

plunger, as the titration begun in Step 3 will be continued in Step

5. Add 8 drops of Starch Indicator Solution (4170WT). Sample

should turn blue.

5. Replace the cap and Titrator. Continue titrating until the blue

color just disappears. Read the test result directly from the scale

where the large ring on the Titrator meets the Titrator barrel.

Record as ppm dissolved oxygen.

NOTE: Each minor division on the Titrator scale equals 0.2 ppm.

6. If the plunger tip reaches the bottom line on the Titrator scale

(10 ppm) before the endpoint color change occurs, refill the

Titrator and continue the titration. When recording the test result,

be sure to include the value of the original amount of reagent

dispensed (10 ppm).

LaMOTTE COM PANY

Help ing Peo ple Solve An a lyt i cal Chal lenges

PO Box 329 • Chestertown • Mary land • 21620 • USA

800-344-3100 • 410-778-3100 (Out side U.S.A.) • Fax 410-778-6394

Visit us on the web at www.lamotte.com

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Lamotte DISSOLVED OXYGEN TEST KIT User Manual Page 4