Indirect calibration for capillary electrophoresis with conductivity detection

• Published in: Analytica chimica acta 2021-05, Vol.1158, p.338397-338397, Article 338397
• Main Authors: Santana, Michele Alves, Lucio do Lago, Claudimir
• Format: Article
• Language: English
• Subjects: Capillary electrophoresis; Conductivity detection; Indirect calibration
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2021.338397

There is a growing interest in conductivity detection for capillary electrophoresis; especially because of capacitively coupled contactless conductivity approach. This robust and general-purpose detector has another lesser-known feature: sensitivity does not depend on the very chemical nature of the analyte, but only on its effective charge and effective mobility. Therefore, the calibration curve prepared for a given species may be used to quantify another one of same charge and mobility. In the absence of a species (calibrant) of exactly the same mobility, two or more calibrants can be used. Provided the sensitivity varies smoothly in the desired region of mobility, it can be mathematically described by a function. For small ranges of mobilities, a linear behavior is expected, and the sensitivity for the analyte can be obtained by interpolation. This technique was investigated for eight different combinations of mono- and double-charged cationic and anionic analytes using buffered and unbuffered background electrolytes (BGEs). For most of the applications, a linear model was enough to describe the sensitivity (0.988