Selectivity (analytical chemistry)

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Selectivity exists in analytical chemistry when a component can be detected and quantified in the presence of other, potentially interfering components using reagents or analytical methods.

For example, the chloride content of a sample can be selectively detected in the presence of other halides ( fluorides , bromides , iodides ) or the sodium ion content can be determined exactly (selectively) in the presence of other alkali and alkaline earth cations . These analytical methods include atomic absorption spectroscopy (AAS) and atomic emission spectrometry .

Selectivity forms the basis of all analytical separation processes due to selective solubilities, crystallizations, enrichments, extractions and adsorption processes. These adsorption processes include the chromatographic methods such as thin layer chromatography (TLC), column chromatography , gas chromatography (GC), high pressure liquid chromatography (HPLC).

When using enantiomerically pure stationary phases, a particularly complex analytical problem can be solved, the determination of the enantiomeric purity of analytical samples. There are methods of enantioselective thin layer chromatography, high pressure liquid chromatography and gas chromatography.

Individual evidence

  1. ↑ (a) Kurt Günther: Thin-layer chromatographic enantiomeric resolution via ligand exchange , Journal of Chromatography 448 (1988) 11-30. (b) Kurt Günther, Jürgen Martens and Maren Schickedanz: Thin-layer chromatographic separation of enantiomers by means of ligand exchange , Angewandte Chemie 96 (1984) 514-515; Angewandte Chemie International Edition in English 23 (1984) 506. (c) Kurt Günther, Maren Schickedanz and Jürgen Martens: Thin-Layer Chromatographic Enantiomeric Resolution , Naturwissenschaften 72 (1985) 149–150. (d) Kurt Günther, Jürgen Martens and Maren Schickedanz: Resolution of Optical Isomers by Thin-Layer Chromatography (TLC). Enantiomeric Purity of L-DOPA , Fresenius Zeitschrift für Analytische Chemie 322 (1985) 513-514. (e) Kurt Günther, Jürgen Martens and Maren Schickedanz: Thin-layer chromatographic separation of stereoisomeric dipeptides , Angewandte Chemie 98 (1986) 284–285; Angewandte Chemie International Edition in English 25 (1986) 278-279.
  2. ↑ E. Busker and Jürgen Martens: Enantiomer separation of N-acylamino acids without previous derivatization , Fresenius Zeitschrift für Analytische Chemie 325 (1986) 559-560.
  3. ↑ Kurt Günther, Jürgen Martens and Maren Messerschmidt: Gas Chromatographic Separation of Enantiomers: Determination of the Optical Purity of the Chiral Auxiliaries ( R ) - and ( S ) -1-Amino-2-methoxymethylpyrrolidine , J. Chromatogr. 288 (1984) 203-205.