Abstract
<jats:p>In this study, a simple, rapid, and reliable methodology was developed for measuring the injected sample volume in capillary electrophoresis and related techniques. The method does not require a calibration curve, nor knowledge of sample viscosity, injection pressure, or time. It is applicable under both significant and weak electroosmotic flow and is compatible with single or sequential injections. The principle of the method is straightforward: a band of neutral molecules is injected before the sample, which has been previously spiked with the same molecule. Classical mechanics allow the absolute calculation of the injected band volume, and the area of this band is simply compared with that of the neutral molecule peak to determine the injected volume of the unknown sample. Experimental validation demonstrated excellent agreement with volumes calculated from Poiseuille’s law. The method was further validated by performing sequential injections of multiple samples, demonstrating high precision across all injections.</jats:p>