Diode laser-based concentration gradient detector for capillary isotachophoresis

✍ Scribed by Jiaqi Wu; Janusz Pawliszyn

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 427 KB
• Volume: 5
• Category: Article
• ISSN: 1040-7685
• DOI: 10.1002/mcs.1220050306

✦ Synopsis

Abstract

A diode laser‐based, universal concentration gradient detector was applied to capillary isotachophoresis (CITP). The inexpensive CITP instrument also included a 30 cm long, 300 μm i.d. capillary, a 5 cm focal length lens and a photodiode light beam position sensor. Factors affecting the sensitivity and performance of the detector, i.e., separation conditions, spatial resolution of the detector, and the concentration of leading electrolyte, were discussed theoretically and experimentally. The diode laser‐based concentration gradient detector appears to be one of the best detectors for CITP due to its high resolution, derivative nature, and low cost. The experimental detection limit reached 4 × 10^−6^ M for small cations, which was near the theoretical value. The detection limit can be further reduced by at least one order of magnitude if a longer capillary is used. The CITP‐concentration gradient detector instrument has high efficiency, and was applied to detect impurities in antidepressant drugs.