Abstract:

A method was developed for the determination of ectoine and hydroxyectoine in fermentation broth samples of moderately saline bacteria using high performance liquid chromatography （HPLC）. Samples were extracted using ethanol extraction, and ectoine and hydroxyectoine standards were dissolved and diluted in ultrapure water. Vertex^TM NH₂ （4.6×250 mm, 5 μm） liquid chromatographic column was used to analyse ectoine and hydroxyectoine in the fermentation broth of moderately halophilic bacteria. Waters 1515 high performance liquid chromatograph with ultraviolet （UV） detector was selected to compare the different detection conditions. The chromatographic conditions were optimized by using acetonitrile （70%） as the mobile phase with a column temperature of 30 ℃, a detection wavelength of 210 nm and a flow rate of 0.8 mL/min. The linearity of ectoine and hydroxyectoine in the fermentation broth samples is good in their respective ranges. The average recoveries of the two samples are in the range of 99.2% to 102%, the precision deviations are in the range of 1% to 2%, the limit of detection is 1.5 μg/mL, the limit of quantification is 5 μg/mL and the separation degree is 1.70. The method is suitable for the separation and determination of ectoine and hydroxyectoine in fermentation broth and for the quantitative analysis of ectoine and hydroxyectoine under laboratory conditions.

Key words: moderately halophile, HPLC, ectoine, hydroxyectoine