Determination of five prostaglandin analogs in eyelash enhancing cosmetics by LC-MS/MS

Objective To determine bimatoprost， tafluprost ethyl amide， latanoprost， travoprost and tafluprost in eyelash enhancing cosmetics by establishing a LC-MS/MS method.

Methods The samples were extracted with a 50% acetonitrile water solution. A salt mixture （4 g NaCl， 1 g MgSO₄） was added to the solution to induce phase separation. After centrifugation and filtration， the analysis of five prostaglandin analogs was performed with an Agilent Poroshell 120 PFP-C18 （2.7 μm， 2.1 mm×100 mm） column， using 0.02% formic acid containing 5 mmol·L^-1 Acetic acid amine and acetonitrile by gradient elution at a flow rate of 0.5 mL·min^-1. The analytes were detected with electrospray ionization source in positive ion mode （ESI⁺） and multiple reaction monitoring （MRM）， and quantified by external standard curve.

Results The results showed that it had a good linearity in the range of locatable ambit of concentration^{with correlation coefficients （r） larger than 0.999. The detection limit of five prostaglandin analogs （LOD） was 0.000 2‒1.5 μg·g-1. The spiked recoveries were 93.2% to 103.5% with a relative standard deviation （RSD） of 1.2% to 3.4%.}

Conclusion The method is simple， rapid and highly sensitive. It is suitable for the determination of five prostaglandin analogs in eyelash enhancing cosmetics.