Quantification of Ions and Organic Molecules, in Nanoliter Samples, in the Absence of Reference Materials

A new analytical methodology, using capillary electrophoresis in indirect UV absorbance mode, is developed for the quantification of analytes in the absence of reference materials. The methodology allows the quantification of organic molecules and/or small ions, anionic or cationic, absorbing or not in the UV range, carrying either one or two electric charges. Two methods of data processing were compared. The first is based on the use of a dynamic simulator of electromigration, and the second uses the Kohlrausch regulating function combined with the electroneutrality equation. The experimental conditions presented in this work allow a precise quantification of anions having electrophoretic mobilities (μ_ep) between -22.71 and -36.92 × 10^-9 m² V^-1 s^-1 and cations with μ_ep between +30.59 and +63.60 × 10^-9 m² V^-1 s^-1 with percent relative errors lower than -5.52%. The effect of the integration errors on the reliability of the results is discussed in detail.