LE0171 : Sampling and Testing Procedures

This practical and highly-interactive course includes practical sessions and exercises where participants will visit the laboratory and they will be introduced to various lab instruments and modern laboratory practices. Practical sessions will be performed using one of the lab equipment in order to apply the theory learnt in the class.
Analytical procedures often start with the instruction to take a given quantity of a representative sample. It is clear that the only perfect sample is the entire lot; anything less carries with it a statistical probability that it will be less than representative. Also, the smaller the sample, the greater the likelihood that it will deviate in composition from the whole. Statistically – greater than 66% of all analytical errors contained in analytical results come from the sampling process. The analytical result may depend on the method used for the analysis, but it always depends on the type of sampling plan used. Knowledge of the potential sampling error is important since if the sampling error is more than about 2/3 of the total error, any attempt to reduce the analytical error is of little value. Therefore, when you are assessing the uncertainty of the final result you should remember the contribution from sampling errors. These errors cannot be evaluated or controlled using standards or reference materials.