Sample preparation

from Wikipedia, the free encyclopedia

The sample preparation is an important step in a chemical analysis method. The samples available after sampling are mostly unsuitable in their original form (river water, soil, ore, etc.) for carrying out methods of instrumental analysis on them . When preparing the sample, it is important to convert the analyte completely, or at least reproducibly, into a homogeneously dissolved form. For this purpose, a solid analysis sample usually has to be dried, crushed and rejuvenated. Under rejuvenation means the statistically representative portions of the sample to arrive at a small amount, which can weigh. In the case of inorganic analyzes, this is generally followed by a digestion or, in the case of organic analytes, an extraction .

All sample preparation steps are prone to random and systematic errors. In terms of extent, they are greater than those in the actual analysis. Large errors in the double-digit percentage range can be expected due to analyte loss or contamination if the necessary care is not taken and internal standards are used. The degree of purity of the chemicals used and the consideration of blank value analyzes are also decisive .

literature

  • Georg Schwedt: Pocket Atlas of Analytics . 2., revised. and exp. Edition. Wiley-VCH, Weinheim 2002, ISBN 3-527-30870-9 .