Development of a capillary electrophoresis system coupled to sequential injection analysis and evaluation by the analysis of nitrophenols

Abstract

A combination of a laboratory-made capillary electrophoresis system and a sequential injection analysis equipment is described. For characterization, the system was successfully applied to the separation and quantification of nitrophenols. A blue LED was used as light source, and hydrodynamic injection was carried out by using a pressure-stable solenoid valve and an inflatable pressure reservoir. A good reproducibility of migration time (0.5%) and peak heights (5%) were obtained. The calibration by using peak heights was found to be linear up to 776 µmol L⁻¹ for all three compounds. The system was robust and reliable for autonomous analysis without observation. All maintenance requirements including the conditioning of the capillary and flushing of both buffer reservoirs were carried out automatically. Instrumentation aspects of the capillary electrophoresis part are compared with former described hyphenated flow systems showing maximal operation versatility. Instrumental control and data evaluation were carried out using the software package AutoAnalysis.

Keywords:

• Nitrophenols
• Capillary electrophoresis
• Sequential injection analysis
• Hyphenation

Acknowledgements

The authors acknowledge the grant from the Conselleria de Economia, Hisenda i Innovació Govern Balear, support from the University of the Balearic Islands, and help from Prof. Dr Bo Karlberg and co-workers from the Department of Analytical Chemistry, Stockholm University, Sweden.

This work is part of the project CTQ2004-01201, ‘Desarrollo de métodos automáticos en flujo para la monitorización y control de bioreactores y depuradoras de aguas residuales’, supported by the Spanish Ministry of Science and Technology.