CHAPTERS:An Optical Brightener Handbook
Step 3: Retrieval
A. Pads are first rinsed in the sampling waters to remove as much sediment as is possible.
B. Then the samples are squeezed to remove as much water as is practicable without tearing or ripping the pad.
Retrieving and rinsing the exposed Optical
Brightener pad in a stream
C. Next the exposed sampling pads are labeled or tagged for cross referencing.
Most tags and labels are made from white paper and contain Optical Brightener and can interfere with the reading of the sample. Labels cut from darker manila envelopes many times do not contain Optical Brightener. All labels regardless of their source should be checked under the U.V. light to make sure they do not contain Optical Brightener before they are used.
Labels should have information written on them as to location, day of placement, and day of removal. They are then stapled to the retrieved sampling pads and placed in a zip lock bag (to prevent cross contamination) and placed in a dark area.
D. After all the pads have been retrieved, cleaned, and labeled they are dried out in a space where they will not come in contact with direct sunlight (preferably overnight) on a monofilament line. Cotton line can not be used as it contains Optical Brightener and can interfere with the reading of the sample.
Exposed Optical Brightener sampling pads
drying on a monofilament line
The monofilament line should either be replaced or wiped clean before and after each drying with a damp non-exposed cotton sampling pad.
