Isolation of choline and choline esters from Krebs-Ringer solution for gas chromatographic determination

✍ Scribed by Dénes Budai; Péter Szerdahelyi; Péter Kása

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 568 KB
• Volume: 159
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(86)90341-6

✦ Synopsis

A simple and efficient novel method for isolating picomole amounts of choline and choline esters in milliliter volumes of Krebs-Ringer solution has been developed. The procedure is based on the observation that the solubility of choline esters in acetonitrile is 104-lo5 times higher than that of the inorganic salt constituents of Krebs-Ringer solution. The glucose content of the medium, which prevented the one-step isolation of choline esters based on acetonitrile extraction from its lyophilizate, was removed using Amberlite CG-50 column chromatography. Bound compounds to the column were elutcd in 0.25 N HCl and lyophilized. The lyophilizate was extracted with acetonitrile, which was then decanted and eliminated by evaporation to dryness. The resultant glucose and salt-free residue can be assayed by gas chromatography. Total recoveries of added choline and choline esters over the entire isolation procedure, measured isotopically and/or gas chromatographically, were 93 and 97%, respectively. Due to the high and close-to-equal recoveries of choline esters, and the high purity of the final product, this procedure is suitable for estimating acetylcholine and choline in neural tissue per&sates by gas chromatography, as was demonstrated by this method using hippocampal slices. 0 1986 Academic PBS, hc.