A rapid and reliable size-exclusion chromatographic method for determination of kojic dipalmitate in skin-whitening cosmetic products

A size-exclusion chromatographic method has been developed to determine the relatively novel skin-whitening agent called kojic dipalmitate (KDP) in skin-whitening cosmetic products.Preliminary experiments were carried out in order to select the solvent for standard and sample solution, and also for mobile phase composition.A PLGel Mixed-D (polystyrene/divinylbenzene co-polymer) column and isocratic mobile phase of pure tetrahydrofuran (at 1.5 mL min−1 flow rate) were used. Detection was carried out by means of an UV/vis spectrometry detector set at 248 nm.A study of interferences reveals that KDP can be determined without interferences coming from cosmetic matrices. Most other cosmetic ingredients usually employed in skin-whitening cosmetic products, such as other whitening agents and common UV filters, do not interfere.The accuracy and precision of the proposed method was tested by the analysis of six laboratory-made and five commercial skin-whitening cosmetic samples.The sensitivity and limit of detection (3 μg mL−1) obtained are suitable for the analysis of this type of samples. The chromatographic run takes less than 8 min to complete.All these features make the method easy to apply to quality control in the cosmetic industry.