Synthesis of novel selenium-containing choline and acetylcholine analogues and their quantitation using a pyrolysis-gas chromatography-mass spectrometry assay

Methods for the synthesis and quantitation of the novel choline analogues, selenonium choline and acetylselenonium choline, are described. An assay procedure utilizing pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) with cold trapping was developed with deuterated d₄-selenonium choline and d₄-acetylselenonium choline as internal standards. The selenonium compounds were ion-pair extracted from tissue with dipicrylamine, washed with 2-butanone, and pyrolyzed prior to GC-MS analysis. The compounds were monitored using selected ion monitoring at m/z 122 and m/z 125 for the non-deuterated and deuterated compounds, respectively. The assay had a sensitivity of 20 pmol of compound taken through the assay and was linear through 20 nmol.