Recap the bottle and store in the cooler for delivery to the lab. The sample must be analyzed within 8 hours. As the sample temperature will rise in your boat, it is advisable to use a depth electronic thermometer. Lake Sample Analysis - Uncap sample bottle and rinse calibrated cylinder with a few mls of sample. Measure exactly 50 mls of sample.
Careful measurement is crucial to accurate measurement of dissolved oxygen.
No special care needs to be taken to avoid introducing bubbles into the sample. Set stirrer to mix sample without splashing. Continue until the solution turns from a strong yellow to a pale yellow. Continue titrating, adding about 5 to 10 digits every few seconds. As the color turns to light blue, slow down, adding about 2 digits every few seconds until the blue just disappears.