The aim of this project is to devise a way to incorporate an internal standard in point-of-care devices based on capillary electrophoresis. Capillary electrophoresis suffers from variations in injected sample amount, applied injection and separation voltages, electroosmotic flow velocity, sample interactions with the wall, etc. etc. These variations are exacerbated when disposable chips are used. An internal standard, added to the sample prior to analysis, can substantially correct for many of these errors. To add such an internal standard is however not simple for a point-of-care device, since it is meant for operation by the patient, who should just perform very simple actions to apply the sample.
In a first stage the project has resulted in an experimental analysis of the improvement in chip-to-chip variance on the addition of internal standard. A considerable improvement was observed, interestingly depending on the type of (ionic) internal standard added [Bidulock et al., Improving chip-to-chip precision in disposable microchip capillary electrophoresis devices with internal standards, Electrophoresis 2015].
At present the project has entered a second project phase, where methods are investigated to add the internal standard to the system. The aim is hereby to have no additional manipulation steps for the patient-operator.