化妆品中的酚酸类物质, 有的作为有效成分而添加, 如： 具有修复皮肤功效的咖啡酸、 能够抗炎抗过敏的没食子酸等； 有的作为防腐剂而添加, 如： 对羟基苯甲酸、 山梨酸等； 有的则属于禁用物质, 被不良商家违法添加, 如： 对苯二酚、 间苯二酚等。 为监控化妆品质量, 对化妆品中酚酸类物质的检测显得尤为重要。 许多研究人员也为此做了相关工作, 以色谱法为主的先分离后分析的方法取得了一定的成功, 但是费时、 费料、 操作复杂等缺点也十分明显； 三维荧光光谱技术具有较高的灵敏度, 但是荧光干扰和光谱重叠对检测有较大的影响, 针对复杂的化妆品样本往往无法得到理想的效果。 为实现化妆品中酚酸类物质的同时定性定量检测, 文章将三维荧光光谱技术与化学计量学的四维校正（也称三阶校正）相结合, 在保证高灵敏度的情况下, 克服未知干扰和数据共线性的影响。 首先, 在咖啡酸（caffeic acid, CA）、 对羟基苯甲酸（p-hydroxybenzoic acid, p-HA）、 对苯二酚（hydroquinone, HQ）的线性范围内选取合适的浓度, 分别在7.00, 7.30, 7.50和7.80四种pH值下配制校正样、 验证样和化妆品样, 这样就得到了激发-发射-pH-样本（EX-EM-pH-Sample）四维数据阵。 其次, 为验证pH值对荧光强度的影响, 选取320 nm作为激发波长, 得到咖啡酸在四种pH值下的发射波长, 发现咖啡酸的荧光强度随着pH值的增加而升高, 表明引入pH值作为第四维的合理性。 最后, 选择合适的组分数将四维数据阵用交替惩罚四线性分解算法（alternating penalty quadrilinear decomposition, APQLD）进行分解和预测, 将分解的光谱与实际光谱比较, 将预测的浓度与实际浓度比较。 实验结果显示无论是验证样还是化妆品样, 分解光谱均能与实际光谱相吻合, 验证样的平均回收率（AR）为100.4%~103.5%, 预测均方根误差（RMSEP）低于0.06； 化妆品样平均回收率（AR）为100.0%~102.2%, 预测均方根误差（RMSEP）低于0.08。 与色谱法研究相比回收率高出大约4%, 且操作简便省时省力, 灵敏度高； 与二阶校正方法相比, 都可以实现在未知干扰下对复杂化妆水体系中多个组分的同时分析, 以“数学分离”代替“物理化学分离”, 快速、 高效、 经济、 环保； 且三阶校正可以克服一定的数据共线性问题, 在一定程度上提高了灵敏度。

For phenolic acids in cosmetics, some are added as active ingredients, such as caffeic acid with skin-repairing effects, gallic acid capable of anti-inflammatory and anti-allergic, etc.; some are added as preservatives, such as p-hydroxybenzoic acid, sorbic acid, etc.; some are prohibited substances illegally added by bad businesses, such as hydroquinone, resorcinol and so on. In order to monitor the quality of cosmetics, the detection of phenolic substances in cosmetics is particularly important. Many researchers have done related work for this purpose. The method of separation and analysis based on chromatography has achieved certain success, but the disadvantages such as being time-consuming and costly and complicated operation are also obvious. Three-dimensional fluorescence spectroscopy has a high sensitivity, but fluorescence interference and spectral overlap have a large impact on detection, and complex cosmetic samples often fail to achieve the desired results. In order to realize simultaneous qualitative and quantitative detection of phenolic acids in cosmetics, the paper combines three-dimensional fluorescence spectroscopy with four-dimensional calibration of chemometrics (also called third-order correction) to overcome unknown interference and the effect of collinearity with the data while ensuring high sensitivity. First, select in the linear range of caffeic acid (CA), p-hydroxybenzoic acid (p-HA), hydroquinone (HQ). At the appropriate concentration, calibration samples, verification samples and cosmetic samples were prepared at the four pH values of 7.00, 7.30, 7.50, 7.80, respectively, so that the excitation-emission-pH-sample (EX-EM-pH-Sample) four-dimensional data were obtained. Secondly, in order to verify the effect of pH on the fluorescence intensity, 320 nm was chosen as the excitation wavelength to obtain the emission wavelength of caffeic acid at four pH values. It was found that the fluorescence intensity of caffeic acid increased with the increase of pH value, indicating the introduction of pH. The value was reasonable as the fourth dimension. Finally, the appropriate component number was selected to decompose and predict the four-dimensional data matrix by alternating penalty quadrilinear decomposition (APQLD). The decomposed spectrum was compared with the actual spectrum, and the predicted concentration was compared with the actual concentration. The experimental results showed that the decomposition spectrum can be consistent with the actual spectrum whether it is a validation sample or a cosmetic sample. The average recovery (AR) of the validation sample was 100.4% to 103.5%, and the predicted root mean square error (RMSEP) was less than 0.06. The average recovery (AR) of cosmetics sample was 100.0%~102.2%, and the predicted root mean square error (RMSEP) was less than 0.08. Compared with chromatographic studies, the recovery rate increased by about 4%, and the operation was simple, time-saving and labor-saving, and has high sensitivity. Compared with the second-order correction method, multiple components in the complex cosmetic system can be realized under unknown interference. Replacing “physical and chemical separation” with “mathematical separation” is fast, efficient, economical and environmentally friendly; and third-order correction can overcome certain data collinearity problems and improve sensitivity to some extent.