Sample Size

As shown in Figure 1.1, the term macro analysis is used for samples whose masses are greater than 0.1 g. A semimicro analysis is performed on samples in the range of 0.01 to 0.1 g, and samples for a micro analysis are in the range 10^-4 to 10^-2 g. For samples whose mass is less than 10^-4 g, the term ultramicro analysis is sometimes used.

 From the classification in Figure 1.1, we can see that the analysis of a 1-g sample of soil for a suspected pollutant would be called a macro analysis whereas that of a 5-mg sample of a powder suspected to be an illicit drug would be a micro analysis. A typical analytical laboratory processes samples ranging from the macro to the micro and even to the ultramicro range. Techniques for handling very small samples are quite different from those for treating macro samples.

Figure 1.1 Classification of analyses by sample size.