General considerations for optimizing a capillary electrophoresis–electrospray ionization time-of-flight mass spectrometry system

Abstract

Modern analytical instrumentation must be able to perform rapid, reliable, and sensitive analysis. The on-line combination of analytical techniques such as capillary electrophoresis (CE), electrospray ionization (ESI) and mass spectrometry (MS) can provide solutions to numerous problems related to complex mixtures of organic/inorganic, or biological materials. Optimum performance of complex instrumentation such as this can be achieved only if each individual component operates with maximum proficiency, and is in full harmony/compatibility with the other components. The present paper reports on the evaluation and optimization of a CE-ESI time-of-flight mass spectrometry (TOF-MS) system. The main features of the instrument are speed and sensitivity. Low amol (3–11) detection limits have been achieved with continuous infusion experiments, and the acquisition rate can be as high as 10 000 spectra s −1. For CE–TOF-MS, minimum detection was in the very-low fmol (1–10) range. The major contributing factors to high quality analysis characteristic to each separate technique are considered, relevant examples are discussed, and fast, and sensitive analysis is demonstrated.