Some new COD tubes appear to have yellow solids stuck to the inside glass surface. Is this a problem?

Document ID

Document ID TE1085

Published Date

Published Date 27/05/2017
Question
Some new COD tubes appear to have yellow solids stuck to the inside glass surface. Is this a problem?
Summary
COD tube vials with yellow orange solids
Answer
After manufacture, this reagent is a turbid, light orange/yellow liquid. Solids stuck to the sides of the tube indicate that they were shipped or storedon their side. While startling in appearance, this rarely presents as a problem in the test procedure.

After preparing the sample and blank by adding 2.00 mL of sample/deionized water to the tube the vials should be closed tightly and inverted several times to mix. The yellow solids will re-enter solution during these inversions. Hold the vials by the cap, as the glass vials get very hot during mixing.

Test a COD Standard Solution to confirm expected response.