Alkyl‐chain selective analysis of phosphoric acid esters with non‐aqueous capillary electrophoresis

Non-aqueous capillary electrophoresis has proved to be an efficient technique for the analysis of phosphoric acid esters. Using an electrolyte based on N-methylformamide, short chain phosphoric acid esters and water insoluble long chain phosphoric acid esters were analyzed simultaneously. The background electrolyte consisted of 15 mM ammonium anthraquinonesulfonate as background chromophore for indirect detection, 10 mM triethylamine, and 0.001% polybrene. It allowed determination of the alkyl chain length of the analytes, and distinction between ethoxylated and non-ethoxylated phosphoric acid esters even in more complex mixtures. The method enabled fast separation within 8 min after uncomplicated sample preparation.