RP-HPLC-MS Determination of Quaternary Ammonium Salts of Mono-, Di-and Tri-ester of Trihydroxyethylamine

Quaternary ammonium salts of mono-, di-and tri-esters of trihydroxyethylamine were separated and determined by RP-HPLC-MS. The sample was extracted thrice with ethylether, and the extracts were combined and evaporated to dryness at 50 ℃ in a water bath. The residue was dissolved with n-propanol, and the solution obtained was used for RP-HPLC-MS analysis, with 10 μL aliquot for sample introduction. DIKMA Inertsil CN-3 column was used as stationary phase and mixtures of n-propanol and water with different ratios were used as mobile phase in the gradient elution. Changed aerosol ionization with positive ion mode and MRM mode were used in MS analysis. Normalization of peak area was adopted in the determination. Linear relationship between values of lgA (A represents the peak area) and mass concentration of quaternary ammonium salts of mono-, di- and tri-ester of trihydroxyethylamine were found in the same range of 0.25-7.5 mg·L-1, with detection limits (3S/N) of 0.08, 0.10, 0.10 mg·L-1 respectively. Precision of the method was tested, values of RSD′s (n=6) found for the 3 quaternary ammonium salts were 10.9%, 8.3% and 3.8% respectively.