Abstract: Objective To establish an HPLC-CAD method for the determination of inositol in oral solution B₁₂. Methods The Agilent Zorbax NH2 (4.6 mm×250 mm, 5 μm) column was used. The mobile phase consisted of acetonitrile-0.5% ethanol solution (90:10), and the flow rate was 1.0 mL·min^-1. The charged aerosol detector (CAD） was used at an atomization temperature of 55℃, a power rate of 2.0, a sampling frequency of 5 Hz with a filtration constant of 10 s. Results Baseline separation was achieved between inositol, sucrose and other peaks. When the concentrations of inositol ranged from 0.090 8 to 1.815 mL·min^-1, the linear equation was Y=331.85X -28.812, the detection limit was 3 μg·mL^-1, with a quantitative limit of 13 μg·mL^-1. The recoveries of 80%, 100% and 120% inositol reference substances were 99.4%, 101.2% and 101.6%, respectively. Conclusion This method is highly specific, sensitive and user-friendly, which can be used for the determination of inositol content in oral solution B₁₂.

Key words: oral solution B₁₂ lysine inositol, inositol, HPLC, charged aerosol detector, determination