Capillary Electrophoresis-mass Spectrometry

These factors determine how rapidly each chemical species migrates through the capillary under the applied electric field. Differences in electrophoretic mobility cause compounds to reach the capillary outlet at different times, while interactions with the surrounding electrolyte can further alter their movement. The resulting separation helps resolve components in chemically complex mixtures before mass analysis.

The high-voltage field supplies the driving force for ion movement through the narrow capillary. Because charged species respond differently to that field, their migration rates are not identical, producing temporal separation. This electrical control is central to the technique because it allows compounds to be distinguished before they enter the mass spectrometer for identification.

The two stages provide complementary information. Electrophoretic separation helps distinguish components in a mixture, whereas mass analysis measures each emerging species according to its mass-to-charge ratio. Combining these results improves molecular identification and supports characterization when several compounds are present together or when conventional chromatographic methods do not provide sufficient resolution.

A sample is introduced into a narrow capillary containing an electrolyte, and a high-voltage electric field drives its charged components through the capillary. As compounds emerge, they are ionized and transferred into the mass spectrometer. The instrument then analyzes their mass-to-charge ratios, combining migration-based separation with molecular information from mass analysis.

This approach is particularly useful for complex mixtures containing metabolites, peptides, proteins, pharmaceuticals, or other chemical species that require both separation and identification. It is also valuable when sample amounts are limited. In such situations, the method can provide compositional and structural information while retaining high separation efficiency.

CE-MS can support trace analysis, molecular identification, structural characterization, and studies of sample composition. Its separation stage reveals differences in electrophoretic behavior, while mass-to-charge measurements help characterize compounds emerging from the capillary. Together, these outputs assist investigations of chemically complex samples, especially when conventional chromatographic approaches leave components insufficiently resolved.