Abstract

This study aimed to develop and validate a method for the analysis of caffeine in complex cosmetic samples, such as sunscreens. Besides, an extraction method of caffeine from coffee oil and from creams, which contains both lipophilic and hydrophilic components, has been developed. The method to analyze caffeine was developed using an isocratic pump, Waters 1515 and an automatic injector Perkin-Elmer Series 200 and an UV detector Perkin-Elmer. As stationary phase, Kromasil C-18 (150 × 4.6 mm ID with particle size of 5 µm) column was used and a mixture of water (pH 4.00)/acetonitrile (80:20, V/V) with a flow rate of 1.5 mL/min as a mobile phase. To extract the caffeine from the formulations and coffee oil, different agitation methods, solvents, and number of treatments were evaluated. The relationship between chromatographic areas and concentration of caffeine presents a linear correlation within the range 0.05–5.00 µg/mL. The precision of this method was very high, as the coefficients of variation were always lower than 6%. The DL of this technique was 3.71 ηg/mL and the QL was 11.23 ηg/mL. Three replicates of the samples obtained by the extraction method were processed obtaining a concentration of caffeine in creams between the experimental and theoretical average value of 7.48%. The literature report methodologies only in aqueous medium, different from this methodology that is fast, economical and can be used in Quality Control in the cosmetic industry. The extraction method of caffeine from matrices has also been successfully developed with absence of interferences.

摘要

本研究旨在开发和验证一种分析复杂化妆品样品（如防晒霜）中咖啡因的方法。此外，还开发了一种从咖啡油和奶油中提取咖啡因的方法，该方法同时含有亲油性和亲水性成分。分析咖啡因的方法是使用等度泵 Waters 1515 和自动进样器 Perkin-Elmer Series 200 和 UV 检测器 Perkin-Elmer 开发的。作为固定相，使用 Kromasil C-18（150 × 4.6 mm ID，粒径 5 µm）色谱柱和水（pH 4.00）/乙腈（80:20，V/V）的混合物，流速为 1.5 mL/min 作为流动相。为了从配方和咖啡油中提取咖啡因，评估了不同的搅拌方法、溶剂和处理次数。色谱面积与咖啡因浓度之间的关系在 0.05–5.00 µg/mL 范围内呈线性相关。该方法的精度非常高，变异系数始终低于 6%。该技术的 DL 为 3.71 ηg/mL，QL 为 11.23 ηg/mL。通过提取方法获得的样品的三个重复进行了处理，得到奶油中咖啡因的浓度在实验平均值和理论平均值之间 7.48%。文献报道了仅在水性介质中使用的方法，不同于这种快速、经济且可用于化妆品行业质量控制的方法。从基质中提取咖啡因的方法也已成功开发，没有干扰。