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Capillary electrophoresis coupled with sheath-flow laser-induced fluorescence (LIF) detection has been shown to offer outstanding sensitivity for chemical and biochemical analysis. However, a major drawback remains with the complexity of the optical configuration traditionally employed. Here we present a simplified confocal optics based on fiber optics and micro gradient-index (GRIN) lenses for modular optical design in capillary electrophoresis with laser-induced fluorescence. We demonstrate the use of the optical system with a sheath-flow cuvette as the laser-induced fluorescence detector for capillary electrophoresis. The system’s performance was established with concentration detection limits of and mass detection limits of 57 zeptomole for a standard sodium fluorescein sample.
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Detection techniques for carbohydrates in capillary electrophoresis – a comparative study
Abstract Capillary electrophoresis methods for the separation of carbohydrates with four different detection techniques, namely direct UV, indirect UV, capacitively coupled conductivity, and laser-induced fluorescence detection, were tested and their performance was evaluated and compared in terms of linearity, limits of detection and quantitation, repeatability, recovery, analysis time, and sample treatment. The test set of analytes comprised sucrose, glucose, and fructose. The effect of using lactose as an internal standard on the individual methods was investigated, too. The results showed that laser-induced fluorescence detection is a technique of choice for applications requiring the detection of very low amounts of reducing carbohydrates. Contactless conductivity detection is favorable when detection sensitivity is not a crucial parameter but fast and reliable analysis is required. When only a UV detector is available as a standard part of capillary electrophoresis instruments, direct UV detection can be used when analysis time is not a critical parameter. For fast analysis with UV detectors, indirect UV detection is the technique of choice. Finally, to verify the applicability of the tested methods, samples of cola beverage, honey, and orange juice were analyzed and the results obtained by all four methods were compared. Graphical abstract
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- Award ID(s):
- 1658615
- PAR ID:
- 10435973
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Monatshefte für Chemie - Chemical Monthly
- Volume:
- 154
- Issue:
- 9
- ISSN:
- 0026-9247
- Page Range / eLocation ID:
- p. 967-975
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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