Sampling can be described as the operations involved in procuring a laboratory size that is a true representative of “a whole lot for a particular analytical exercise. Sampling is indeed the most difficult step in the entire analytical process; however, it remains the only key to the success of the whole analytical programme. Good sample irrespective of the type or method of sampling should possess the following properties:
1.A good sample must have the same characteristic or features with that of the original population from where it is selected.
- The nature of the sample must be the same with that of the population and must remain so throughout the analytical exercise.
3.The number of samples should be large enough to make the result reliable.
Indeed, the methods used in collecting a true representative sample depends on various factors which include:
- The knowledge and experience of the analyst or sampler
The result of survey on the nature, size and configuration of the site of materials to be sampled.
3.The level of sensitivity of the desired result.
It is necessary to note that, there is virtually no single technique that can fulfil all requirements in any sampling case. Modifications and combination of some techniques may be necessary in some sampling cases.