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Updated: Aug 19, 2026

Sample Preparation for Probe Electrospray Ionization Mass Spectrometry
Published on: February 19, 2020
Spurious serotonin dimer formation using electrokinetic injection in capillary electrophoresis from small volume
Jeffrey N Stuart1, Nathan G Hatcher, Xin Zhang
1Department of Chemistry and Beckman Institute, 600 S. Mathews Ave 63-5, University of Illinois, Urbana, IL 61801, USA. jsweedle@uiuc.edu
Abstract:
One normally assumes that the analytical measurement process does not introduce spurious compounds. Capillary electrophoresis is a separation method frequently used for small-volume biological measurements. We demonstrate the potential for creating new peaks in a capillary electropherogram when using electrokinetic injections and illustrate the potential deleterious effects with biological samples involving serotonin and nitric oxide measurements. Specifically, when measuring the serotonin content from individual neurons using electrokinetic injections from 360 nL stainless steel vials, we detect a new peak that we identify as a serotonin dimer. We do not observe this peak when using hydrodynamic injections.
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