Column liquid chromatography with diode laser-induced fluorescence detection of carboxylic acids after pre-column derivatisation

• Published in: Analytica chimica acta Vol. 315; no. 1; pp. 209 - 216
• Main Authors: Mank, Arjan J.G., Beekman, Marco C., Velthorst, Nel H., Brinkman, Udo A.Th, Lingeman, Henk, Gooijer, Cees
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.10.1995; Elsevier
• Subjects: Analytical chemistry; Carboxylic acids; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Fluorimetry; Laser-induced fluorescence; Naproxen; Other chromatographic methods; Red-absorbing label; Laser-induced fluorescence; Carboxylic acids; Fluorimetry; Red-absorbing label; Naproxen; Carboxylic acid; Precolumn; Detection limit; Antiinflammatory agent; Fluorescence; Derivatization; Fluorescence spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(95)00334-V

Several pre-column approaches to fluorescence derivatisation of carboxylic acids, compatible with diode laser-induced fluorescence (DIO-LIF) detection, were compared. For this purpose red-absorbing labels containing hydrazide, bromoacetamide and iodoacetamide functionalities were studied. The sensitivity of DIO-LIF detection is illustrated by the (3–10) × 10 −12 M (75–250 amol) detection limit for various derivatised carboxylic acids. The real-life detection limit for the carboxylic acids is 3 × 10 −8 M , because derivatisation is not quantitative at lower concentrations. Derivatised n-alkylcarboxylic acids and non-steroidal anti-inflammatory drugs are easily separated by column liquid chromatography, despite the attachment of the bulky red-absorbing labels. The determination of the anti-inflammatory drug naproxen in saliva is shown as an example.