Question

1. Describe the steps involved in a sampling operation. 2. Discuss the purpose of a sampling step in an analysis. 3. Differentiate between a bulk sample and a laboratory sample 4. Discuss the differences between an aliquot and a laboratory sample 5. What are the factors considered in choosing a representative sample?

Answer 1

Sampling operation

The sampling operation should include details of the health and safety aspects of sampling. It should ensure that representative samples are taken in sufficient quantity for testing in accordance with specifications. Closures and labels should preferably be such that unauthorized opening can be detected. Samples should never be returned to the bulk.

Laboratory Sample

The sample may be too large to conveniently analyze using a laboratory procedure and so only a fraction of it is actually used in the final laboratory analysis.

Bulk Sample

This is the total product produced or manufactured from the process in the plant. Small amount of this sample is taken for the analysis in the laboratory is named laboratory sample.

A aliquots is a portion of a larger whole, especially a sample taken for chemical analysis or other treatment. The term is usually applied to fluids. When a laboratory sample or test sample is ‘aliquoted’ or otherwise subdivided, the portions have been called split samples.

All the following factors will ensure a representative sample.

1. random sampling
2. stratified sampling.
3. alternative is periodic sampling
4. carton sampling.