To prepare the series of standard cosmetics samples, analytefree day cream samples (2.0 g each) were put into several beakers (10 mL, Tianjin Tianbo Glass Instrument Co., Ltd., Tianjin, China), into which a series of standard solutions (400L of methanol solutions containing different concentrations of analytes) were added, respectively, tomake the standard samples. Samples were kept stirring for 30 min to achieve the homogeneous distribution of analytes inside cosmetics. These mixtures were partially dried under low vacuum conditions (10 mTorr, 25◦C), if necessary, until the final mass loss was 400 mg for each beaker. Due to its volatility, the methanol evaporated easily within minutes while the other ingredients were kept, imposing no significant alteration of its viscosity after the analyte adulteration.