LaMotte SMART3 Colorimeter - Manual (Page 142)

acid.
For greater accuracy, a minimum of three repetitions should be performed and the
results averaged.
Some samples may be digested completely in less than two hours. The
concentration may be measured at 15 minute intervals while the vials are still
hot until the reading remains unchanged. The vials should be cooled to room
temperature before the fi nal measurement is taken.
COD, Low Range SMART3 Test Procedures 11.10
Test P
rocedures