Sample Processing

Sample Processing

After collecting the samples from the assigned river source, the samples have to be processed before any test can be done.  Sample processing is a process done to a sample to prepare it for testing.  In the case of the water samples that were collected, the first step was to filter the sample.  This is an important step due to the fact that the sample that was used wasn’t entirely pure.  The accuracy of the results depends upon the purity of the sample provided. The sample that was used in this case comes from a river, which contains several such as dirt from the river bed and many microscopic creatures that live in the water.
There are two common ways to do filtration, either by gravity or vacuum filtration.  The first uses gravity to filter the sample.  The set up is quite simple.  The materials that are needed are a filter paper, a funnel, something to hold the funnel, and a container to collect the liquid after it is filtered.

The second filtration method is done by creating a vacuum to filter; this produces a faster filtration system than the gravity method.  For this procedure, a Buchner funnel, a Buchner flask, filter paper, rubber tubing, and access to an aspirator are needed to do this procedure.

It is also important to take the filter paper into account because if the pores in the filter paper are too small the ions that you want to analyze could be taken out.  To prevent this it is good to know what type of experiment you are doing and what pore size of the filter paper you should use.  The pore size of the filter paper can also determine how long it takes to filter.

To accomplish the filtration you slowly pour the mixture into the funnel that has a filter in it.  A sample might need to be filtered several times before it is tested to ensure that the purest sample is obtained.   Either method will work for the filtration but gravity filtration requires less equipment than vacuum filtration.  After the filtration of the sample, tests can be done such as pH, buffer capacity and analysis of the cation and anion contents of the unknown sample using ion chromatography.

Content on this web page authored by Stormie Harlan, Yoji Takishima, Grace Campos & Ifeoma Okekeane

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