Indirect calibration for capillary electrophoresis with conductivity detection

Author(s)

Santana, Michele Alves ^[1] ; Lago, Claudimir Lucio do ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Chem, Dept Fundamental Chem, Av Prof Lineu Prestes 748, BR-5508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Analytica Chimica Acta; v. 1158, MAY 8 2021.
• Web of Science Citations: 0

Abstract

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 < R-2 < 0.998), but for ample range of mobilities, the inclusion of a hyperbolic term was needed (0.995 < R-2 < 0.999). This technique has a great potential to be used in field applications and in laboratories when the analytes are unstable or they are not available to be used in the preparation of standard solutions. (C) 2021 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/06642-1 - Formation and properties of adducts of organic hydroxy-compounds with carbonate in aqueous medium and biological conditions
• Grantee: Claudimir Lucio Do Lago
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/13137-5 - Formation and properties of hemiesters of carbonic acid in aqueous medium
• Grantee: Claudimir Lucio Do Lago
• Support Opportunities: Research Projects - Thematic Grants