- 學位論文
利用高效能液相層析法配合螢光偵測器 開發香粧品中丙二醛之分析方法
Determination of malondialdehyde in cosmetic products by high-performance liquid chromatography with fluorescence detection
摘要
丙二醛(Malondialdehyde, MDA)是多元不飽和脂肪酸過氧化所產生氧化產物之一。丙二醛為量測生物系統中過氧化壓力狀態的重要標記。此外，丙二醛也被認為是評估富含脂質食物的脂質過氧化作用指標。為了解香粧品中丙二醛的含量，本研究旨在利用高效能液相層析儀開發檢測防曬乳霜及防曬乳液內丙二醛的分析方法，並將所開發的分析方法應用於評估經紫外線照射後之香粧品中丙二醛含量的變化情形。本研究利用硫化巴比妥酸與丙二醛進行衍生化反應，以甲醇為萃取溶液，以甲醇:磷酸二氫鉀=50:50 (v/v)為移動相溶媒，經由逆相C18層析管柱分離，以螢光檢測器在激發及散射波長分別為532 nm 和553 nm的條件下偵測MDA-TBA 複合物。線性範圍為0.01-4.86 ?嵱具良好的相關係數 (r>0.995)。在1.2 mL/min流速之下，四分鐘內可完成樣品分析。同日內及異日間分析的相對標準偏差介於0.8-3.2%，添加回收率大於90.9%，顯示所研發分析方法的精密度與準確度。在檢測隨機取得六種防曬乳霜及防曬乳液產品經紫外線(UVA或UVB)照射後之丙二醛含量變化方面，結果顯示其中一種防曬乳霜與兩種防曬乳液在較長時間之UVA或UVB的照射下MDA濃度顯著增加(p< 0.05)。
並列摘要
Malondialdehyde (MDA), one of the major secondary oxidation products of peroxidized polyunsaturated fatty acids, has been shown to be an important marker for the measurement of oxidative stress in biological systems. In addition, MDA has also been shown to be a relevant indicator for the assessment of lipid peroxidation in lipid-rich food. In the present study, to demonstrate the presence of MDA in cosmetics, an HPLC method for the determination of MDA in cosmetic creams and lotions was developed. The proposed method was applied to evaluate the effect of ultraviolet irradiation on MDA level in the cosmetic products. The proposed method is based on derivatization of MDA with thiobarbituric acid (TBA). High-performance liquid chromatographic separation is based on a reversed-phase C18 column and methanol-KH2PO4 (50:50, v/v) as a mobile phase. The MDA–TBA adduct was monitored by fluorescence detection, with excitation at 532 nm and emission at 553 nm. The linearity in the range of 0.01-4.86 ?嵱 presents a good correlation coefficient (r>0.995). The analysis time was less than 4 min, at a flow rate of 1.2 mL/min. The precision demonstrated by the relative standard deviation (RSD) of 0.8-3.2% was observed. The analytical recovery of MDA after supplementing creams and lotions with tetraethoxypropane was over 90.9%, which confirmed the accuracy of the proposed method. The proposed method was applied to measure MDA level in six kinds of cosmetic creams and lotions after ultraviolet A or B irradiation. The results indicate that one of the cosmetic creams and two of the cosmetic lotions show significant elevation in MDA level after ultraviolet A or B irradiation for a longer period.