Choline is a water soluble essential nutrient that is produced in the body in small quantities. Choline is a precursor of acetylcholine which is an important neurotransmitter involved in muscle control and memory. Choline is a small, highly polar quaternary amine and will not be retained using a C18 column. The zwitterionic nature of Syncronis HILIC makes it ideal for the retention of this class of compound. This application note demonstrates the successful analysis of acetylcholine and choline using a Syncronis HILIC 1.7 µm column.

Choline is a water-soluble quaternary amine essential to methyl metabolism, transmembrane signaling, and normal brain development. This application update is an IC method that simultaneous determines choline and other cations. The method uses electrolytic generation of a methanesulfonic acid (MSA) eluent for a 2 mm Dionex IonPac CS19 column. This method has been reviewed by expert review panel (ERP) and approved as an AOAC Official First Action Method (AOAC Method 2012.20).

Choline and acetylcholine are quaternary ammonium cations which are noted for their activities as neurotransmitters. This is an older application note that shows these compounds can be determined by IC. Today we would probably use an IonPac CS19 column as shown in Application Update 189.

This work presents IC-based methods for the detection and quantification of methacholine and possible impurities in solutions used to assess bronchial asthma of subjects evaluated in respiratory function labs and epidemiological field studies. Methacholine assay involves diluting the original solution (dissolved in 0.9% sodium chloride with or without 0.4% phenol) 1000-fold with deionized water, then analyzing the sample on a cation RFIC system. These methods demonstrate high precision and accuracy for both methacholine and possible impurities present in amounts approaching 1%.

A simple RFIC method is described for determination of carbachol, bethanechol, and choline in 25 min with a Dionex IonPac CS17 column. Methanesulfonic acid (MSA) eluent is delivered isocratically by an Eluent Generator (EG). Use of an EG eliminates eluent preparation errors and helps ensure retention time reproducibility. The sensitivity of suppressed conductivity detection allows carbachol determination in ophthalmic solutions with only a simple sample dilution.