Same-day batch measurement of glycine betaine, carnitine, and other betaines in biological material.

Glycine betaine, carnitine, carnitine esters, butyrobetaine, and proline betaine (stachydrine) concentrations in biological materials can be reliably measured in 100-microliters samples, with a detection limit below 1 mumol/liter. The procedure is suitable for batches of more than 30 specimens and it is possible to obtain a single result within 2 h. The betaines are extracted into an acetonitrile:methanol mixture, dried with anhydrous disodium hydrogen phosphate containing argentous oxide. The 4-bromophenacyl ester derivatives are formed using 4-bromophenacyl triflate as reagent, in the presence of solid magnesium oxide as base. The derivatives are separated by high-performance chromatography on a silica column, in a mixed partition and ion-exchange mode.