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Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
Published on: August 19, 2013
Chloroisothiocyanatoquinolines as fluorogenic derivatizing agents for primary and secondary amines
S C Bernstein1, S K Abrams, K J Leckrone
1Department of Chemistry, Antioch College, Yellow Springs, OH 45387.
Journal of Pharmaceutical and Biomedical Analysis
|January 1, 1993
Summary
Two novel fluorogenic derivatizing agents for liquid chromatography (LC) were synthesized. These agents efficiently label amines, offering sensitive fluorescence detection with minimal interference.
Area of Science:
- Analytical Chemistry
- Organic Chemistry
Background:
- Prechromatographic derivatization enhances analyte detectability in chromatography.
- Fluorogenic reagents are valuable for sensitive trace analysis.
Purpose of the Study:
- To synthesize and characterize new chloro-isothiocyanatoquinoline derivatives as prechromatographic derivatizing agents.
- To evaluate their reactivity with amines and suitability for liquid chromatography (LC).
Main Methods:
- Synthesis of 2- and 4-chloro-3-isothiocyanatoquinoline.
- Reaction kinetics studies with primary and secondary amines.
- Hydrolysis rate analysis in aqueous base.
- Evaluation of derivatization interference with UV and fluorescence detection.
- Sensitivity and linearity assessment using fluorescence detection.
Main Results:
- Synthesized compounds 4 and 5 react smoothly with amines to form fluorescent thiazoloquinolines.
- Hydrolysis of reagents 4 and 5 interferes with UV detection but not significantly with fluorescence detection.
- Derivatives of 4 are unprotonated, while derivatives of 5 are protonated in typical RP-LC mobile phases.
- Protonated derivatives of 5 exhibit a large Stokes shift (~200 nm).
- Fluorescence detection provides high sensitivity (0.8 µM at S/N=2) and linearity over two concentration decades.
Conclusions:
- The new chloro-isothiocyanatoquinoline reagents are effective for prechromatographic derivatization of amines.
- Fluorescence detection is superior to UV detection due to reagent hydrolysis and excess reagent interference.
- These agents offer a sensitive and linear method for amine analysis in LC.
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