超高效液相色谱-二极管阵列检测法同时测定化妆品中22种防晒剂

建立了一种超高效液相色谱-二极管阵列检测法同时测定不同种类化妆品中22种防晒剂的方法。样品首先加入少量四氢呋喃,涡旋、分散、混匀(蜡质化妆品可于50 ℃超声,以便分散完全),然后加入0.1%(v/v)甲酸乙醇溶液振摇、超声提取,稀释、过滤后经Poroshell 120 EC-C₁₈(100 mm×4.6 mm, 2.7 μm)分离,乙腈-异丙醇-50 mmol/L乙酸铵水溶液(含0.05%(v/v)甲酸)梯度洗脱,二极管阵列检测器检测,检测波长311 nm,外标法定量。结果表明,22种防晒剂在各自的范围内线性关系良好,相关系数(r)均在0.998以上。选取两种不同基质类型的样品,在低、中、高3个不同添加水平下的平均回收率为85.2%~112.3%,相对标准偏差(RSD)在0.5%~6.5%之间,方法的检出限和定量限分别为0.7~64 mg/kg和2.4~215 mg/kg。在2、10、50 mg/L3个水平的混合标准溶液的稳定性试验中,甲酚曲唑三硅氧烷组分12 h内稳定,其余组分36 h内稳定。采用该方法测定市售16份化妆品中的防晒剂,其中5份样品检测结果与厂家提供的配方值匹配良好。与《化妆品安全技术规范》(2015年版)收载方法相比,该方法在流动相组成和提取溶剂选择方面,摒弃了四氢呋喃和高氯酸等腐蚀性溶剂的使用,改善了弱极性组分的提取效率,同时增加了检测组分二苯酮-2,被测物稳定性更好,实验操作更便利高效,分离效果更好,结果更准确,兼顾绿色环保,可用于化妆品防晒剂的日常检测。

Simultaneous determination of 22 sunscreen agents in cosmetics by ultra-high-performance liquid chromatography using diode array detector

A fast and simple ultra-high-performance liquid chromatography using diode array detector (UHPLC-DAD) technique has been developed for the simultaneous determination of 22 sunscreen agents (UV filters), viz. phenylbenzimidazole sulfonic acid (PBS), terephthalydene dicamphor sulfonic acid (TDS), benzophenone-4 (BZ4), camphor benzalkonium methosulfate (CBM), benzophenone-2 (BZ2), benzylidene camphor sulfonic acid (BCS), benzophenone-3 (BZ3), 3-benzylidene camphor (3BC), isoamyl p-methoxycinnamate (IMC), 4-methylbenzylidene camphor (MBC), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), octocrylene (OCR), butyl methoxydibenzoyl methane (BDM), ethylhexyl dimethyl PABA (EDP), ethylhexyl methoxycinnamate (EMC), homosalate (HS), ethylhexyl salicylate (ES), diethylhexyl butamido triazone (DBT), ethylhexyl triazone (ET), drometrizole trisiloxane (DRT), methylene bis-benzotriazolyl tetramethylbutylphenol (MBP), and bis-ethylhexyloxyphenol methoxyphenyl triazine (EMT) in cosmetic products. Different parameters, such as column type, oven temperature, mobile phase composition, and detection wavelength, were studied. The best chromatographic separation was obtained under the following conditions: Poroshell 120 EC-C₁₈ (100 mm×4.6 mm, 2.7 μm) column set at 25 ℃ and gradient acetonitrile-isopropanol-water (containing 50 mmol/L ammonium acetate and 0.05% (v/v) formic acid) as the mobile phase, pumped at a flow rate of 0.5 mL/min, with a wavelength of 311 nm. The proposed UHPLC-DAD technique provided separation of the 22 target sunscreen agents within 35 min, with the optimized sample pretreatment procedure below. First, samples were mixed thoroughly by adding 2 mL or 5 mL tetrahydrofuran, followed by vortex and dispersal. If the wax samples were still not homogenized completely, an ultrasonic dispersal protocol with heating to 50 ℃ was adopted. Second, the homogeneous samples were ultrasonically extracted with ethanol containing 0.1% (v/v) formic acid. The developed method showed good linear relationships, with correlation coefficients of no less than 0.998. Two kinds of samples with different matrix types were fortified at three levels. The average spiked recoveries of 22 UV filters ranged from 85.2% to 112.3%, with the relative standard deviations (RSDs) ranging from 0.5% to 6.5%. The limits of detection were between 0.7 and 64 mg/kg, and the limits of quantification ranged from 2.4 mg/kg to 215 mg/kg. Moreover, the stabilities of the mixed standard solutions at the levels of 2, 10, and 50 mg/L were tested. The stability results showed that drometrizole trisiloxane was stable for 12 h, while the others were stable for 36 h. The reliability of the developed method was demonstrated by applying it to 16 commercial sunscreen-containing cosmetic samples obtained from the Chinese market. The levels determined in this study agreed well with those of five commercial samples (such as emulsion and cream). The method developed was remarkably different from the standard method, which is mentioned in the Safety and Technical Standards for Cosmetics (2015 edition), especially in terms of mobile phase composition and extraction solvent. Compared to the standard method, this method bypassed the use of large amounts of corrosive solvents like tetrahydrofuran and perchloric acid, thus improving the extraction efficiency of low-polarity components like drometrizole trisiloxane, methylene bis-benzotriazolyl tetramethylbutylphenol, and bis-ethylhexyloxyphenol methoxyphenyl triazine, and the analytes were well separated with better stability. Benzophenone-2 was added to this method as another detection component. The good analytical features, as well as their environment-friendly characteristics, make the presented method suitable not only for routine analysis in cosmetics industries, but also as a candidate reference method for sunscreen analysis.