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SOP6 – Water Quality Analysis
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Acid soaking
a) Soak the filter cups, frits, syringes and Gelman filter parts in the acid bath for a few
minutes. Place small articles in the metal dipping container.
Note: The Gelman filter screens are sensitive to acid. They should be placed in the
metal container and dipped into the acid bath. Then, they should be soaked in several
changes of DI for several minutes each. Otherwise, they will rust.
b) Graduated cylinders and other glassware can be soaked in acid overnight if necessary.
The sample bottles and caps are immediately scrubbed with a brush, then freshwater rinsed 3
times and air-dried.
The 10 Erlenmeyer flasks used for regrowth are fresh water rinsed 3 times then DI rinsed 3
times. These flasks and the 2 labeled 500 ml to-deliver graduated cylinders are air dried, then
covered with blue sterile wrap and foil, and autoclaved before next use.
7.6. Transport and Delivery to Nutrient Analytical Services Laboratory (NASL)
Samples are transported back to NASL in an iced cooler, then immediately placed in a freezer at
-20 °C or below until analysis.
The data sheet and the sample labels are checked for accuracy and completeness, then the data
sheet is signed by both the delivery person and acceptance person. A sign copy is returned to the
MERC files.
7.7. Frequency of QC Sample Collection
The frequencies of QC sample collection for water quality samples outlined in Table 11 of the
ETV protocols, version 5.1 (September 2011) will be followed.