- Retrieve an empty nutrient rack from the lab fridge if needed and record the color key with CESL electronic sample log.
- Wear latex or vinyl gloves; never touch the inside of the cap or tube since residue from your glove can contaminate the sample. If unavoidable or you drop the lid – rinse several times before capping the sample.
- Nutrients are normally drawn from the middle valve – fill the tube with ~25mls, cap loosely, shake/rinse then dump. Repeat three times.
- Double check the tube number matches the rosette bottle number.
- Fill the tube completely then flick out several mls so the sample reaches the base of the neck/threads. Cap tightly.
- Draw one sample per rosette bottle.
Once all the nutrient samples are drawn:
- Carefully tip the nutrient rack until you can see the seawater sample through the cap of each tube – if a tube is empty, double-check the sample log and fill if necessary.
- fill out a sample label (from the sample label clipboard) with the time, your initials, total number of samples
Wrap the label around tube #1 and carefully re-insert into rack
- return the filled rack to the nutrient fridge right away.
- add your initials to the bottom of CESL's sample log’s nutrient column
Common mistakes are empty tubes that shouldn’t be; contaminated samples; and duplicate draws – two sample tubes filled from the same bottle