An improvement of separation and response applying post-column compensation and one-step acetone protein precipitation for the determination of coenzyme Q10 in rat plasma by SFC-MS/MS

• A novel method for determination of coenzyme Q10 by SFC-MS/MS is developed for the first time.
• A low toxicity, environmental and economical of CO2 were used as mobile phase.
• Compensation solvent of methanol containing 2 mM ammonium acetate was used to improve the sensitivity.
• Acetone was used as precipitation protein agent firstly.

Coenzyme Q10 (CoQ10) solid dispersion was prepared to improve its oral bioavailability due to the poor solubility of CoQ10. To evaluate the pharmacokinetic behaviors of CoQ10 solid dispersion, a simple, rapid, sensitive and environment friendly method for the determination of CoQ10 in rat plasma was developed. In this study, samples were prepared by one-step protein precipitation with acetone and then the supercritical fluid chromatography-electrospray ionization tandem mass spectrometry (SFC-ESI–MS/MS) method was used. The separation was achieved by an ACQUITY UPC2™ BEH 2-EP column (100 mm × 3 mm, 1.7 μm) maintained at 35 °C, using carbon dioxide (≥99.99%) and methanol (85:15, v/v) as the mobile phase at a flow rate of 1.0 ml/min. To improve the response and sensitivity, the compensation solvent of methanol with 2 mM ammonium acetate at a flow rate of 0.2 ml/min was used and the total analysis time was only 1.5 min for each sample. The detection was carried out on a tandem mass spectrometer with electrospray ionization (ESI) source and the mass transition ion pair was m/z 881.0 → 197.0 and 285.1 → 193.0 for CoQ10 and diazepam, internal standard (IS), respectively. Calibration curve was linear over the concentration range of 2.00–500.00 ng/ml (r2 ≥ 0.998) with a lower limit of quantification of 2.00 ng/ml. The intra- and inter-day accuracy and precision were below 15% for all quality control samples. The proposed method was rapid, accurate and reproducible, which was suitable to compare the pharmacokinetic behaviors in rats after a single oral dose of 100 mg/kg CoQ10 solid dispersion or tablets.