When collecting samples for ultratrace metals analyses, it is important to ensure that the samples that are ultimately analysed by the laboratory are representative of the environmental conditions from which the samples were collected. Therefore, the samples must be collected in a manner and in containers that maintain the integrity of the sample and the metals being measured from the time the sample is collected to the time it is analyzed by the laboratory.
It is also important to minimize exposure of the sample to the ambient environment. Extraneous contamination by metals in the sampling environment is a risk that increases significantly as the requirement for increased analytical sensitivity increases. Metal contamination can occur almost anywhere from many different sources including: dust; automobile exhaust; cigarette smoke; some personal care products; etc. It is important, therefore, to keep sample containers capped until the sample is collected. Then cap the sample container as soon as possible after collection, keeping them sealed until they are opened by the laboratory.