ABSTRACT
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.
ABSTRACT
ObjectiveTo establish a high⁃performance liquid chromatography （HPLC） quantitative method for the determination of epicatechin （EC）， （-）⁃epicatechin gallate （ECG）， （-）⁃epigallocatechin （EGC）， （-）⁃epigallocatechin gallate （EGCG）， （-）⁃gallocatechin （GC）， （-）⁃gallocatechin gallate （GCG）， （-）⁃catechin gallate （CG）， cianidanol （CD） and gallic acid （GA） in cosmetics. MethodsSamples were prepared by ultrasonic extraction and followed by high-speed centrifugation of the extraction solution. The supernatant was filtered by 0.45 μm Millipore filter. The continued filtrate was taken for analysis. A reversed phase column， Kromasil 100-5 C18 （5 μm， 4.6 mm×250 mm） was used with 0.05% trifluoroacetic acid buffer and methanol as mobile phase under the condition of gradient elution. Diode array detection （DAD） method was used for the determination. Qualitative and quantitative determination was conducted in 10 batches of commercially available cosmetics. ResultsThe relative standard deviations （RSD） were in the range of 0.11%-6.30% （n=3）； the recoveries were in the range of 84.4%-114.7%. The method showed a good linearity within the concentration range of 0.49-105.39 mg·L-1 （r>0.995）. The detection limit was 5 μg·g-1. In 10 batches of commercially available cosmetics， three batches showed positive result， which was consistent with the UV spectrum of the standard. ConclusionThis method is efficient， sensitive and accurate. It is applicable to the determination of EC， ECG， EGC， EGCG， GC， GCG， CG， CD and GA in cosmetics.
ABSTRACT
ObjectiveAn HPLC method was established for the determination of azelaic acid and potassium azeloycinate diglycinate in cosmetics. MethodsThe samples were extracted with 60 mmol·L-1 sodium hydroxide water solution-methyl alcohol. After centrifugation and filtration， the analysis of azelaic acid and potassium azeloycinate diglycinate was performed with a SVEA C8（250 mm×4.6 mm， 5 μm） column， using 15 mmol‧L-1 potassium dihydrogen phosphate solution （pH=3.0） and acetonitrile for gradient elution at a flow rate of 1.0 mL·min-1.The analytes were detected with UV detector， and quantified by external standard curve. ResultsThe results showed a good linearity in the range of 5‒1 000 μg‧mL-1 with correlation coefficients （r） larger than 0.999. The detection limit of azelaic acid and potassium azeloycinate diglycinate （LOD） was 0.020% and 0.015%， respectively. The spiked recoveries were 87.66% to 108.96% with the relative standard deviation （RSD） of 0.6% to 3.3%. ConclusionThe method is simple， rapid and highly sensitive. It is suitable for the determination of azelaic acid and potassium azeloycinate diglycinate in cosmetics.