Use deionized water if available.
Detergent. Wash with detergent. Use a test-tube brush where possible. When not possible to use a brush, fill
labware with detergent solution and agitate by shaking.
Rinsing. Rinse at least two times with clean water, until there are no visible suds. Then rinse once more with
220.127.116.11. Handling and Storing Reagents.
Shelf-life, Stability. There is a limited useful lifetime (shelf life) for most reagents in the WQAS-PM. An
expiration date is printed on the label of each container. If this date has passed, the reagent may no longer be
useful and should be replaced.
Powder Pillows. Where possible dry powdered reagents are packaged in polyethylene or foil packages called
powder pillows. Each contains the proper amount of reagent for one test. Open the polyethylene pillows with the
nail clippers provided in the WQAS-PM. Open the foil pillows by tearing the foil along the tear line.
Storing. Store reagents in the designated areas within the WQAS-PM. Do not store them in direct sunlight or
extremes of heat and cold, as this will shorten their useful life (shelf life).
Avoid Contamination. Do not leave a reagent bottle open when it is in use. This may cause the reagent to
degrade due to reaction with the air. Do not remove reagent from a bottle with a dropper or pipet that has not
been thoroughly cleaned and dried. This may contaminate the reagent.
18.104.22.168. Collecting Water Samples.
Proper technique is important in getting a representative water sample that is not contaminated. The following
techniques are recommended.
Use a clean sample container.
Whenever possible take samples from the center of the vessel or duct, or away from shorelines, as applicable.
Take samples from below the water surface.
Take samples as close to the source as possible to avoid contamination by pipes etc.
Before taking a sample, rinse the sample bottle or container three times with water from the source to be tested.
Avoid contaminating the sample with hands or fingers.
Enclosed water systems should be allowed to run for a sufficient time to flush the system.
The sample container should be filled slowly with a gentle stream to avoid turbulence and air bubbles.
Water samples from wells should be collected after the pump has run long enough to be delivering water that is
representative of the ground water feeding the well.
Multiple samples from different depths and locations within a water source will more truly represent the condition
of the body of water to be tested.