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1 2004

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Zastosowanie derywatyzacji w metodach chromatograficznych w analizie śladowej

Kalembkiewicz J., Ruman T.

Wiadomości Chemiczne

2004

[Z] 58, 3-4

263--276

Derivatization is a modern method used in both organic and inorganic analytical chemistry. Application of derivatization to determine trace quantity of compounds requires very sensitive detection techniques. That combined with separation of analyzed compounds, makes the chromatographic systems like GC (gas chromatography) and HPLC (high performance liquid chromatography) especially useful in the analysis. There are mainly three routes in trace analysis of derivatized compounds. One can obtain derivative before performing a column separation (pre-column technique), which can be done both inside or outside chromatographic apparatus, or after column separation (post-column technique). The third method is based on dcrivatization reaction taking place simultaneously with column separation and requires special column filling which is resistant to derivatization reagents. There are several methods used to obtain derivatized compounds suitable for chromatographic methods. Acylation adapted to determine traces of amphetamine, methamphetamine and their metabolites allows lowering the detection level to 1 ppb. Very important part of derivatization methods in trace analysis is a determination of heavy metals via sodium tetraalkylborate alkylation with AED detection (atomic emission detection). Organometallic traces can be derivatized with tetraborate salts with AAD detection (atomic absorption detection). Less known methods like condensation and esterification are also very useful with suitable detector. For example, determination of ketones and aldehydes via derivatization with pentafluorophenylhydrazine allows to lower detection level down to 10^(-14) mol. Esterification of fatty acids with 9-(2-hydroxyethyl)carbazole performed on HPLC column gives full separation of esters with detection limit being around 45 fmol.