| Summary: | 碩士 === 嘉南藥理科技大學 === 化妝品科技研究所 === 100 === In this study, ultraviolet - visible absorption spectroscopy and high-performance liquid chromatography with ultraviolet detection were used to investigate the permeability of methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, phenoxyethanol, methyl isothiazolinone, dimethylol-dimethylhydantoinc, imidazolidinyl urea and two commerical composite preservatives through thin film of plastic packaging materials, such as polyethylene (PE), linear low density polyethylene (LLDPE) or non-oriented casting polypropylene (CPP) In ultraviolet absorption spectroscopy, the absorption behavior of preservatives in the wavelength range of UV radiation(200-400nm) were first measured and the detection limit and quantification limit were calculated from the concentration and absorbance relationship at maximum absorption wavelength of respected preservatives. In high performance liquid chromatography, the influence of components and pH of the mobile phase on the chromatogram were studied to determine the optimum chromatographic condition. The detection limit and quantification limit of high performance liquid chromatographic method were also calculated. The above methods with the use of Franz cell were applied to study the permeability of preservatives through thin plastic film of packaging materials for cosmetics,
The results showed that, ultraviolet absorption spectrometry shows higher sensitivity than high performance liquid chromatographic method, but it is not possible to resolve the absorption of individual component in a mixture. However, ultraviolet absorption spectrometry is still a better method to study the interation of a single preservative and thin plastic film.
In the results of preservatives permeability through PE film from ultraviolet absorption spectrometry, methyl isothiazolinone shows much higher permeation rate than other preservatives and Imidazolidinyl Urea shows the least. However, phenoxyethanol shows the highest permeation rate in the study of the prentration behavior of mixed preservatives and analyzed by high performance liquid chromatography and the permeration rate of p-hydroxybenzoate esters were inverse proporational to the molecular size of the preservatives. Therefore, whether the permeability of preservative is changed after mixed is worth furth study.
Compared the permeability of a single preservative through other plastic films, methyl isobutyl thiazolinone shows highest permeability through the CPP film and most of all test preservatives shows lower permeability through LLDPE film. Therefore, it is suggested that LLDPE film has better barrier effect for preservatives.
It is concluded that this study provides informations on the permeability of preservative through plastic film, These informations could be an important reference when choosing the appropriate packaging material for cosmetics. But the penetration behavior of mixed preservatived is worth furth study.
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