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Various other preparation techniques are also being used for liquids. An increase in the detection sensitivity is obtained by drying up the solvent of a liquid dropped onto a sample carrier (see Sections 11.3.2 and 12.4.1). This method enriches the analytes, and at the same time reduces the spectral background, thereby increasing the analytical sensitivity.

Other possibilities are the transfer of a liquid directly into a quasi-solid body, for instance, by gel formation or by the absorption of the liquid in a porous material such as alumina or coal. The precipitation of solutes by a targeted chemical reaction and its recovery by filtering or the absorption of solutes and the analysis of the adsorbent is also possible. In all cases, depending on the composition of the primary material, the most favorable option and chemical reaction must be selected. To ensure sufficient analytical accuracy, test measurements on reference samples of known composition should be made, in order to determine parameters such as recovery rate and reproducibility before the actual analysis.

Some of the preparation procedures are described in connection with the corresponding applications in Chapter 11.