Abstract:

An analytical method to determine 17 underivatized amino acids in donkey-hide glue was
established with reversed-phase high performance liquid chromatography (HPLC) coupled with
evaporative light-scattering detection (ELSD). A PrevailTM C18 column was used with the mobile phase
of acetonitrile-0.7% trifluoroacetic acid containing 5.0 mmol/L heptafluorobutyric acid. Under the
condition of solvent gradient elution, the temperature of drift tube was 115 ℃ and the gas flow
rate was 2.5 L/min. The 17 amino acids were separated within 25 min. The good linearities between
the logarithm of peak area and logarithm of mass concentration of amino acids were obtained in a
range of mass concentrations from 0.073 g/L to 2.327 g/L. The recoveries of 17 amino acids were
93.5%-104.8% with the relative standard deviations (RSDs) of 0.58%-2.88%. The lowest detection
limits of amino acids were from 18.2 mg/L to 54.6 mg/L with 3 times the signal to noise ratio.
This HPLC-ELSD method is rapid, simple and accurate. It can be used for the direct determination of
17 underivatized amino acids in donkey-hide glue. It also serves as a good reference for the
determination of amino acids in other fields, such as pharmaceutical analysis.

Key words: amino acid, donkey-hide glue , evaporative
light-scattering detection (ELSD), underivatized, reversed-phase high performance liquid chromatography (RP-HPLC)