Filtration - LaMotte smart spectro 2 Operator's Manual

fi ve times and it may be raised to the surface for examination. The inner chamber of the
sampling device is lifted out and portions of the water sample are carefully dispensed for
subsequent chemical analysis.
A Snap-Plunger Water Sampler (LaMotte Code 1077) is another "in-depth" sampling
device which is designed to collect large samples which can be used for a multitude of
tests. Basically, this collection apparatus is a hollow cylinder with a spring loaded plunger
attached to each end. The device is cocked above the surface of the water and lowered
to the desired depth. A weighted messenger is sent down the calibrated line to trip the
closing mechanism and the plungers seal the sample from mixing with intermediate
layers as it is brought to the surface. A special drain outlet is provided to draw off samples
for chemical analysis.
Sampling of Closed System
To obtain representative samples from confi ned water systems, such as pipe lines, tanks,
vats, fi lters, water softeners, evaporators and condensers, diff erent considerations are
required because of chemical changes which occur between the inlet and outlet water.
One must have a basic understanding of the type of chemical changes which occur for the
type of equipment used. Also, consideration should be given to the rate of passage and
retaining time for the process water.
Temperature changes play an important part in deciding exactly what test should be
performed. Process water should be allowed to come to room temperature, 20–25°C,
before conducting any tests.
When drawing off samples from an outlet pipe such as a tap, allow sample to run for
several minutes, rinsing the container several times before taking the fi nal sample. Avoid
splashing and introduction of any contaminating material.
 FILTRATION
When testing natural waters that contain signifi cant turbidity due to suspended solids
and algae, fi ltration is an option. Reagent systems, whether EPA, Standard Methods,
LaMotte or any others, will generally only determine dissolved constituents. Both EPA and
Standard Methods suggest fi ltration through a 0.45 micron fi lter membrane, to remove
turbidity, for the determination of dissolved constituents.** To test for total constituents,
organically bound and suspended or colloidal materials, a rigorous high temperature acid
digestion is necessary.
**LaMotte off ers a fi ltering apparatus: syringe assembly (Code 1050) and membrane
fi lters, 0.45 micron, (Code 1103).
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