Loading...
Please wait, while we are loading the content...
Similar Documents
Improving the sensitivity of confocal laser induced fluorescence detection to the sub-picomolar scale for round capillaries by laterally shifting the laser focus point.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Zhu, Ying Chen, Niannian Fang, Qun |
| Copyright Year | 2013 |
| Abstract | This paper describes a simple and efficient approach to reduce the background level of confocal laser induced fluorescence (LIF) detection for round capillaries by laterally shifting the laser focus point. A phenomenon of spontaneous separation of the fluorescence and reflected laser beams at the pinhole of a confocal LIF system when the laser focus point deviates from the center of a capillary channel to the sides was observed for the first time. On the basis of this phenomenon, the reflected laser light from the capillary-air interfaces could be mostly eliminated with a spatial filtering pinhole. A comprehensive study on the phenomenon and optimization of the shift distance was carried out using both experimental and simulation methods. A best shift distance of ±20 μm was obtained, with which background intensity could be significantly reduced by 98.9%, while fluorescence intensity was only reduced by 25.7%, resulting in an improvement of signal-to-noise ratio of 8.3 times, compared with that at a shift distance of 0 μm usually used in most of the confocal LIF systems for round capillaries. A limit of detection of 66 fM was obtained for sodium fluorescein. To demonstrate its potential as an on-column sensitive detector for microscale separation systems, the present system was coupled with a capillary electrophoresis system for separation of four fluorescein isothiocyanate labeled amino acids with concentrations of 100 pM. |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/c3an00345k |
| PubMed reference number | 23772440 |
| Journal | Medline |
| Volume Number | 138 |
| Issue Number | 16 |
| Alternate Webpage(s) | http://www.rsc.org/suppdata/an/c3/c3an00345k/c3an00345k.pdf |
| Alternate Webpage(s) | https://doi.org/10.1039/c3an00345k |
| Journal | The Analyst |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
