Related Experiment Video
Updated: Aug 10, 2026

Automated Hydrophobic Interaction Chromatography Column Selection for Use in Protein Purification
Published on: September 21, 2011
Non-linear calibration functions in ion chromatography with suppressed conductivity detection using hydroxide eluents
Thomas Brinkmann1, Christian H Specht, Fritz H Frimmel
1Research Institute of the German Gas and Water Works Association at the Engler-Bunte-Institut, University of Karlsruhe. fritz.frimmel@ciw.uni-karlsruhe.de
Abstract:
The linearity of calibration curves in ion chromatography with suppressed conductivity detection using hydroxide eluents was investigated. Theoretical calibration curves were derived for strong electrolytes and weak monobasic acids and the results compared with experimental data. At low concentrations up to 1 micromol l(-1) the autoprotolysis of water induces left-curved calibration functions even for strong electrolytes like nitrate. The experimental data are best described by a quadratic function, the differences between linear and quadratic regression being up to 10%. At higher concentrations the calibration curves for strong electrolytes are linear. Due to incomplete dissociation, the calibration curves for weak mono- and dibasic acids show a right curvature. Thus, depending on the analyte and the concentration range of interest, analysts should carefully choose between a linear and a quadratic regression function.
Related Concept Videos
Titration Calculations: Weak Acid - Strong Base
For the titration of 25.00 mL of 0.100 M CH3CO2H with 0.100 M NaOH, the reaction can be represented as:
Controlled-Current Coulometry: Coulometric Titration
The fundamental requirements for coulometric titrations are (1) 100% efficiency in the reagent-generating electrode reaction and (2) a stoichiometric and preferably rapid reaction between the generated...
EDTA: Indirect and Alkalimetric Titration
High-Performance Liquid Chromatography: Types of Detectors
Ion-Exchange Chromatography
Controlled-Current Coulometry: Overview

