三维荧光光谱结合四线性分解算法测定化妆品中的酚酸类物质

引用本文

张慧, 王书涛, 张立娟, 商凤凯, 张艳, 李明珊, 王玉田. 三维荧光光谱结合四线性分解算法测定化妆品中的酚酸类物质[J]. 光谱学与光谱分析, 2020, 40(2): 506-511.
ZHANG Hui, WANG Shu-tao, ZHANG Li-juan, SHANG Feng-kai, ZHANG Yan, LI Ming-shan, WANG Yu-tian. Determination of Phenolic Acids in Cosmetics by Three-Dimensional Fluorescence Spectroscopy Combined with Quadratic Decomposition Algorithm[J]. Spectroscopy and Spectral Analysis, 2020, 40(2): 506-511. 复制到剪切板

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三维荧光光谱结合四线性分解算法测定化妆品中的酚酸类物质

张慧, 王书涛, 张立娟, 商凤凯, 张艳, 李明珊, 王玉田

燕山大学河北省测试计量技术及仪器重点实验室, 河北秦皇岛 066004

作者简介: 张慧, 女, 1995年生, 燕山大学电气工程学院硕士研究生 e-mail: zhang_hui@163.com

收稿日期:2018-12-18 接受日期:2019-05-15 网络出版日期:2020-02-12

基金项目:

国家自然科学基金项目(61471312, 61771419)和河北省自然科学基金项目(F2017203220)资助

摘要

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。

关键词: 酚酸类物质; 三维荧光光谱; 交替惩罚四线性分解算法

中图分类号:O657.3 文献标志码:A

Determination of Phenolic Acids in Cosmetics by Three-Dimensional Fluorescence Spectroscopy Combined with Quadratic Decomposition Algorithm

ZHANG Hui, WANG Shu-tao, ZHANG Li-juan, SHANG Feng-kai, ZHANG Yan, LI Ming-shan, WANG Yu-tian

Measurement Technology and Instrument Key Lab of Hebei Provice, Yanshan University, Qinhuangdao 066004, China

Abstract

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.

Keyword: Phenolic acids; Three-dimensional fluorescence spectroscopy; Alternating penalty quadrilinear decomposition

文章图片

引言

随着我国经济的快速增长以及人们生活水平的提高, 化妆品与美容行业得到了蓬勃的发展。近年来, 我国的化妆品监管机制逐渐成熟, 标准制修订工作逐渐加强, 但是仍有一些化妆品添加成分的检测方法存在缺陷^[1], 如何更准确地进行定性定量成为了研究人员关注的热点。

咖啡酸作为一种生物还原剂, 常常添加到化妆品中用来修复皮肤损伤, 更是药物化妆品质量控制的指标之一^[2], 有必要对其检测方法进行深入研究。对羟基苯甲酸作为防腐剂添加到化妆品中, 可以使化妆品免受微生物污染, 但是研究表明它也是导致化妆品过敏性和接触性皮炎的原因之一^[3], 所以必须控制其在化妆品中的用量。对苯二酚可作为一种美白剂, 但研究发现经常使用对苯二酚会产生皮肤炎等副作用, 因此欧盟将对苯二酚列为化妆品中的违禁物质, 由于廉价易得效果好, 常被非法添加于化妆品中, 有效的检测显得尤为重要。

冯亚男等^[2]建立同时测定化妆品中多个生物还原剂的HPLC法, 平均回收率均在98.0%~102.0%范围内。 Wei等^[4]利用分散液相微萃取的方法同时测定化妆品中的六种防腐剂, 得到实际样品回收率为81.0%~103.0%。朱丽^[5]利用二阶校正测定化妆品中的对苯二酚, 加标回收率为99.7%~103.5%。然而对于这些常用的分析方法, 一般需要先分离再分析, 虽然能够成功测定, 但是费时、费料、耗精力^[6]。将荧光分析技术与二阶校正方法相结合虽然省时简单, 但在数据出现散射和重叠时往往得不到理想的效果^[7]。

为避免费时且繁琐的分离手段, 消除光谱干扰带来的影响, 文章通过引入pH值构建四维数据矩阵, 利用交替惩罚四线性分解算法, 以“ 数学分离” 代替“ 化学及物理分离” , 直接、简便、快速地对化妆品中的三种酚酸类物质进行同时测定, 为化妆品成分的准确检测提供了方法, 具有重要的实用价值和应用前景。

1 方法原理

1.1 四线性模型

三线性成分模型也被称之为PARAFAC模型, 将三线性成分模型扩展至四维可以获得四线性成分模型。在四线性成分模型中, 四维数据矩阵X^I^×^J^×^K^×^L中的每一个元素x_ijkl可以表示如式(1)

$\begin{array}{l} x_{ijkl} = \overset{N}{\sum_{n = 1}} a_{in} b_{jn} c_{kn} d_{\ln} + e_{ijkl} \\ i = 1, 2, \dots, I; j = 1, 2, \dots, J; \\ k = 1, 2, \dots, K; l = 1, 2, \dots, L \end{array}$ (1)

其中, a_in, b_jn, c_kn和d_ln分别表示潜在轮廓矩阵A_I_×_N, B_J_×_N, C_K_×_N和D_L_×_N中的元素, e_ijkl表示四维残差数据阵列的元素。 N为四线性模型的总组分数。

1.2 交替惩罚四线性分解(APQLD)算法

APQLD算法可以看作是交替惩罚三线性算法的扩展, 按照交替惩罚三线性分解算法的理论, 将其扩展到四维可以获得以下四个目标函数^[8]

$\begin{array}{l} σ_{1} (A) = \overset{I}{\sum_{i = 1}} ‖ X_{i ...} - B diag (a_{i}) D^{T} ‖^{2} F \\ σ_{2} (B) = \overset{J}{\sum_{j = 1}} ‖ X_{. j ..} - C diag (b_{j}) A^{T} ‖^{2} F \\ σ_{3} (C) = \overset{K}{\sum_{k = 1}} ‖ X_{.. k .} - D diag (c_{k}) B^{T} ‖^{2} F \\ σ_{4} (D) = \overset{L}{\sum_{l = 1}} ‖ X_{... l} - A diag (d_{l}) C^{T} ‖^{2} F \end{array}$ (2)

按照以上目标函数, 基于交替最小二乘原理, 固定A, B和C, 最小化σ (D)求解D; 固定B, C和D, 最小化σ (A)求解A; 固定C, D和A, 最小化σ (B)求解B; 固定D, A和B, 最小化σ (C)求解C; 从而可以得到以下四个等式^[9]

$\begin{array}{l} A = (\overset{K}{\sum_{k = 1}} \overset{L}{\sum_{l = 1}} X_{.. kl} (B + q (B^{+})^{T} W_{B}) diag (c_{(k)}) diag (d_{(l)})) + q \overset{J}{\sum_{j = 1}} \overset{K}{\sum_{k = 1}} X_{. jk .}^{T} (D^{+})^{T} W_{D} diag (b_{(j)} diag (c_{(k)})) \cdot \\ (\overset{K}{\sum_{k = 1}} \overset{L}{\sum_{l = 1}} diag (c_{(k)}) diag (d_{(l)}) (B^{T} B + \\ q W_{B}) diag (c_{(k)}) diag (d_{(l)})) + \\ q \overset{J}{\sum_{j = 1}} \overset{K}{\sum_{k = 1}} W_{D} (diag (b_{(j)} diag (c_{(k)} {))}^{2})^{+} \end{array}$ (3)

$\begin{array}{l} B = (\overset{L}{\sum_{l = 1}} \overset{I}{\sum_{i = 1}} X_{i .. l} (C + r (C^{+})^{T} W_{C}) diag (d_{(l)}) diag (a_{(i)})) + r \overset{K}{\sum_{k = 1}} \overset{L}{\sum_{l = 1}} {X^{T}}_{.. kl} (A^{+})^{T} W_{A} diag (c_{(k)} diag (d_{(l)})) \cdot \\ (\overset{L}{\sum_{l = 1}} \overset{I}{\sum_{i = 1}} diag (d_{(l)}) diag (a_{(i)}) (C^{T} C + \\ r W_{C}) diag (d_{(l)}) diag (a_{(i)})) + \\ r \overset{K}{\sum_{k = 1}} \overset{L}{\sum_{l = 1}} W_{A} (diag (c_{(k)} diag (d_{(l)} {))}^{2})^{+} \end{array}$ (4)

$\begin{array}{l} C = (\overset{I}{\sum_{i = 1}} \overset{J}{\sum_{j = 1}} X_{ij ..} (D + s (D^{+})^{T} W_{D}) diag (a_{(i)}) diag (b_{(j)})) + s \overset{L}{\sum_{l = 1}} \overset{I}{\sum_{i = 1}} X_{i .. l}^{T} (B^{+})^{T} W_{B} diag (d_{(l)} diag (a_{(i)})) \cdot \\ (\overset{I}{\sum_{i = 1}} \overset{J}{\sum_{j = 1}} diag (a_{(i)}) diag (b_{(j)}) (D^{T} D + \\ s W_{D}) diag (a_{(i)}) diag (b_{(j)})) + \\ s \overset{L}{\sum_{l = 1}} \overset{I}{\sum_{i = 1}} W_{B} (diag (d_{(l)} diag (a_{(i)} {))}^{2})^{+} \end{array}$ (5)

$\begin{array}{l} D = (\overset{J}{\sum_{j = 1}} \overset{K}{\sum_{k = 1}} X_{. jk .} (A + p (A^{+})^{T} W_{A}) diag (b_{(j)}) diag (c_{(k)})) + p \overset{I}{\sum_{i = 1}} \overset{J}{\sum_{j = 1}} {X^{T}}_{ij ..} (C^{+})^{T} W_{C} diag (a_{(i)} diag (b_{(j)})) \cdot \\ (\overset{J}{\sum_{j = 1}} \overset{K}{\sum_{k = 1}} diag (b_{(j)}) diag (c_{(k)}) (A^{T} A + \\ p W_{A}) diag (b_{(j)}) diag (c_{(k)})) + \\ p \overset{I}{\sum_{i = 1}} \overset{J}{\sum_{j = 1}} W_{C} (diag (a_{(i)} diag (b_{(j)} {))}^{2})^{+} \end{array}$ (6)

其中, p, q, r和s为惩罚因子, 使用算法时应选择合适的值, 当p=q=r=s=0时, APQLD算法将等同于4-PARAFAC算法。

2 实验部分

2.1 试剂与仪器

咖啡酸标准品(CA)、对羟基苯甲酸(p-HA, 99.5%)、对苯二酚(HQ, 99%)、色谱级甲醇、色谱级乙醇购于上海阿拉丁生化科技股份有限公司。某品牌液态化妆品(cosmetic)购于广州贝途贸易有限公司。通过混合0.02 mol· L^-1的Na₂HPO₄和0.02 mol· L^-1的NaH₂PO₄溶液得到pH值分别为7.00, 7.30, 7.50和7.80的磷酸盐缓冲溶液。实验用水均为二次蒸馏水。

实验药品的准确称取用FA1004精密电子秤实现。实验样本的三维荧光光谱数据由Edinburgh Instruments公司生产的FS920稳态荧光光谱仪测得, 该仪器的光谱荧光响应范围为200~900 nm, 液氮制冷范围为77~320 K, 激发光源为功率450 W的脉冲氙灯, 信噪比为6 000:1, 检测样本时均使用1 cm石英比色皿进行激发发射扫描。

2.2 仪器参数

仪器参数设置如下: 激发波长范围为210~330 nm, 间隔为4 nm; 发射波长范围为280~480 nm, 间隔为2 nm; 为避免一级瑞利散射, 起始发射波长始终滞后起始激发波长10 nm。扫描速度为12 000 nm· min^-1; 电压为550 V; 狭缝宽度为5.0/5.0 nm。

2.3 样本配制

储备液和工作液的配制: 分别精确称取对羟基苯甲酸(p-HA)10.00 mg、咖啡酸(CA)5.00 mg、对苯二酚(HQ)10.00 mg, 用甲醇溶解并定容至50 mL棕色容量瓶中, 作为储备液, 储存于4 ℃冰箱中。实验时用50 mL混合溶液(甲醇-水, 1:1, V/V)稀释储备液, 得到对羟基苯甲酸(p-HA)、咖啡酸(CA)、对苯二酚(HQ)工作液的浓度分别为40, 10和10 μ g· mL^-1。

校正样的配制: 取8个10 mL棕色容量瓶, 编号为1— 8号, 分别加入不同体积各物质的工作液(使各物质浓度在其线性范围内), 并用混合溶液(甲醇-磷酸盐缓冲液, 1:1, V/V)定容。

验证样的配制: 取4个10mL棕色容量瓶, 编号为9— 12号, 分别加入不同体积各物质的工作液(使各物质浓度在校正样浓度范围内), 并用混合溶液(甲醇-磷酸盐缓冲液, 1:1, V/V)定容。

化妆品样的配制: 取4个10 mL棕色容量瓶, 编号为13— 16号, 分别加入50 μ L液态化妆品以及不同体积各物质的工作液(使各物质浓度在校正样浓度范围内), 并用混合溶液(甲醇-磷酸盐缓冲液, 1:1, V/V)定容。

2.4 数据

16个样本分析物浓度如表1所示, 通过引入pH值构建四维数据, 16个样本在4个pH值下重复设计, 得到一个大小为31× 101× 4× 16的四维EX-EM-pH-sample数据阵, 对此数据阵进行后续处理。

表1 样本配制浓度(μ g· mL^-1) Table 1 Sample concentrations (μ g· mL^-1)

3 结果与讨论

3.1 pH值对荧光强度的影响

以单组分的咖啡酸(CA)为例, 其三维荧光光谱如图1所示, 可见它的荧光峰位置在320 nm/420 nm(EX/EM)。

	Figure Option View Download New Window
	图1 咖啡酸三维荧光光谱Fig.1 Three-dimensional spectrum of CA

为观察不同pH值对荧光强度的影响, 固定激发波长为320 nm, 得到咖啡酸在不同pH值下的发射波长如图2所示, 可见在实验设置的四种pH值下, 咖啡酸的荧光强度随着pH值的增加而升高。这表明pH值的变化可以影响荧光强度, 实验选用pH值构建四维数据比较合理。

	Figure Option View Download New Window
	图2 不同pH值咖啡酸的发射光谱Fig.2 Emission spectrum of CA in different pH

3.2 定性分解

取8个校正样和4个验证样, 在四种pH值下构成31× 101× 4× 12(EX-EM-pH-sample)的四维数据阵, 取组分数为3进行APQLD分解, 结果如图3所示, 在分析物光谱严重重叠的情况下, 利用算法分解的光谱与四种分析物的真实光谱基本吻合, 分解效果较好。

	Figure Option View Download New Window
	图3 定性分解图Fig.3 Qualitative decomposition spectrum

取8个校正样和4个化妆品样, 在四种pH值下构成31× 101× 4× 12(EX-EM-pH-sample)的四维数据阵, 取组分数为4进行APQLD分解, 结果如图4所示, 在含有化妆品的情况下, 该算法仍然可以较好地分解出四种分析物以及复杂背景体系中的干扰成分。

	Figure Option View Download New Window
	图4 定性分解图Fig.4 Qualitative decomposition spectrum

3.3 定量预测

根据分解算法定性分析后得到的浓度矩阵, 对相对荧光强度和各组分浓度进行回归分析, 得到4个验证样和4个化妆品样的各组分浓度预测结果如表2所示。无论验证样还是化妆品样, 均得到了较好的预测效果, 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。

表2 浓度预测结果 Table 2 Concentration prediction results

4 结论

验证了pH值对待测物质荧光强度的影响, 说明根据pH值构建四维数据的合理性。 APQLD算法能够实现化妆水复杂体系中四种酚酸类物质的同时定性定量分析, 定性分解光谱与实际光谱基本吻合, 定量预测平均回收率优于引言中提到的色谱法、萃取法以及二阶校正方法。

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[1]	LIN Xiao-jia, HE Min-heng, CHEN Xiao-zhen, et al(林晓佳, 何敏恒, 陈晓珍, 等). Contemporary Chemical Industry(当代化工), 2017, (6): 1256. [本文引用:1]
[2]	FENG Ya-nan, WANG Meng-li, XIE Hong-ying, et al(冯亚男, 王梦丽, 谢红英, 等). China Measurement & Test(中国测试), 2015, (6): 52. [本文引用:2]
[3]	ZHENG Rong, RU Ge, WANG Ke(郑荣, 茹歌, 王柯). Chin. J. Health Lab. Technol. (中国卫生检验杂志), 2016, (19): 2758. [本文引用:1]
[4]	Wei H Y, J Z. University Chemistry Research: English Edition(高等学校化学研究: 英文版), 2014, 30(3): 368. [本文引用:1]
[5]	ZHU Li(朱丽). High Order Analytical Instruments Combined with Second Order Correction are Used for Cosmetics and Food Safety Detection( 高阶分析仪器结合二阶校正用于化妆品食品安全检测). Hunan University(湖南大学), 2017. 73. [本文引用:1]
[6]	WU Hai-long, LI Yong, KANG Chao, et al(吴海龙, 李勇, 康超, 等). Chinese Journal of Analytical Chemistry(分析化学), 2015, (11): 1629. [本文引用:1]
[7]	Pagani A P, Ibañez G A. Microchemical Journal, 2017, 132: 211. [本文引用:1]
[8]	WANG Shu-tao, LIU Ting-ting, GAO Feng-kai, et al(王书涛, 刘婷婷, 高凤凯, 等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2018, 38(8): 2441. [本文引用:1]
[9]	YIN Xiao-li(尹小丽). Multidimensional Chemical Correction is Used to Study the Dynamic Process of Food Quality Safety and Drug Hydrolysis( 化学多维校正用于食品质量安全及药物水解动态过程研究). Hunan University(湖南大学), 2016. 161. [本文引用:1]

2017

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... 近年来, 我国的化妆品监管机制逐渐成熟, 标准制修订工作逐渐加强, 但是仍有一些化妆品添加成分的检测方法存在缺陷^[1], 如何更准确地进行定性定量成为了研究人员关注的热点 ...

2015

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... 咖啡酸作为一种生物还原剂, 常常添加到化妆品中用来修复皮肤损伤, 更是药物化妆品质量控制的指标之一^[2], 有必要对其检测方法进行深入研究 ...

... 冯亚男等^[2]建立同时测定化妆品中多个生物还原剂的HPLC法, 平均回收率均在98 ...

2016

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... 对羟基苯甲酸作为防腐剂添加到化妆品中, 可以使化妆品免受微生物污染, 但是研究表明它也是导致化妆品过敏性和接触性皮炎的原因之一^[3], 所以必须控制其在化妆品中的用量 ...

2014

0.0

Wei H

, J

. University Chemistry Research: English Edition(高等学校化学研究: 英文版), 2014, 30(3): 368.

A simple and rapid sample preparation method of dispersive liquid-liquid microextraction(DLLME) was applied in the simultaneous determination of six parabens in the aqueous cosmetics. The analysis was performed on gas chromatography coupled with a flame ionization detection(GC-FID). The mixed solution containing 30 mu L of chloroform(extraction solvent) and 300 mu L of tetrahydrofuran(dispersive solvent) was rapidly injected into the sample solution for the purpose of microextraction. After that, the solution mentioned above was centrifuged at 4000 r/min for 10 min, and then the organic sediment phase was detected by GC-FID. The effects of experimental parameters, such as the extraction solvent and the volume of it, and the dispersive solvent and the volume of it, on the yield of the extraction were studied in detail. Under the optimum conditions, the enrichment factors of the target analytes range from 87 to 214. Linearity ranges are 0.05-10.0 mu g/mL for methylparaben and 0.025-5.0 mu g/mL for the other five parabens. The relative standard deviations(RSDs) are lower than 8.2%(n=6). The proposed method was applied to the analysis of six parabens in eleven aqueous cosmetics. The recoveries of the target analytes in the spiked real samples are in the range of 81.0%-103%.

[Wei Hongmin; Yang Jinjuan; Zhang Hanqi; Shi Yuhua] Jilin Univ, Coll Chem, Changchun 130012, Peoples R China.

A simple and rapid sample preparation method of dispersive liquid-liquid microextraction(DLLME) was applied in the simultaneous determination of six parabens in the aqueous cosmetics. The analysis was performed on gas chromatography coupled with a flame ionization detection(GC-FID). The mixed solution containing 30 μL of chloroform(extraction solvent) and 300 μL of tetrahydrofuran(dispersive solvent) was rapidly injected into the sample solution for the purpose of microextraction. After that, the solution mentioned above was centrifuged at 4000 r/min for 10 min, and then the organic sediment phase was detected by GC-FID. The effects of experimental parameters, such as the extraction solvent and the volume of it, and the dispersive solvent and the volume of it, on the yield of the extraction were studied in detail. Under the optimum conditions, the enrichment factors of the target analytes range from 87 to 214. Linearity ranges are 0.05―10.0 μg/mL for methylparaben and 0.025―5.0 μg/mL for the other five parabens. The relative standard deviations(RSDs) are lower than 8.2%( n =6). The proposed method was applied to the analysis of six parabens in eleven aqueous cosmetics. The recoveries of the target analytes in the spiked real samples are in the range of 81.0%―103%.

... Wei等^[4]利用分散液相微萃取的方法同时测定化妆品中的六种防腐剂, 得到实际样品回收率为81 ...

2017

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ZHU

(朱丽). High Order Analytical Instruments Combined with Second Order Correction are Used for Cosmetics and Food Safety Detection( 高阶分析仪器结合二阶校正用于化妆品食品安全检测). Hunan University(湖南大学), 2017. 73.

... 朱丽^[5]利用二阶校正测定化妆品中的对苯二酚, 加标回收率为99 ...

2015

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... 然而对于这些常用的分析方法, 一般需要先分离再分析, 虽然能够成功测定, 但是费时、费料、耗精力^[6] ...

2017

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... 将荧光分析技术与二阶校正方法相结合虽然省时简单, 但在数据出现散射和重叠时往往得不到理想的效果^[7] ...

2018

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... 2 交替惩罚四线性分解(APQLD)算法APQLD算法可以看作是交替惩罚三线性算法的扩展, 按照交替惩罚三线性分解算法的理论, 将其扩展到四维可以获得以下四个目标函数^[8] ...

2016

0.0

YIN

Xiao-li

(尹小丽). Multidimensional Chemical Correction is Used to Study the Dynamic Process of Food Quality Safety and Drug Hydrolysis( 化学多维校正用于食品质量安全及药物水解动态过程研究). Hunan University(湖南大学), 2016. 161.

... 从而可以得到以下四个等式^[9] ...