防晒霜紫外线透光率的测定及防晒效果分析

Measure of Sunscreen Cream Transmittance in UV Wave Range and Analysis of Sun Protection Effect

SPF(sun protection factor)和PA(protection UVA)指数分别反映了防晒用品对太阳光的中波紫外线UVB(ultraviolet B)和长波紫外线UVA(ultraviolet A)的抵抗能力,研究了防晒霜的防晒参数和透光率之间的关系,得到了一个简单并有意义的结果,并用光谱分析实验验证了这个结果的可靠性。利用紫外可见光分光光度计,通过乙醇—乙醚混合溶剂法测量了市面上常见品牌不同SPF和PA指数的69份防晒霜膏体样本中长波紫外线的透光率。测量结果表明光谱分析方法可以有效地区分不同SPF和PA标值的防晒霜,并可以鉴别防晒霜上所标示的指标是否准确,从而为检测防晒用品的防晒指数提供了一种行之有效的方法。如果防晒霜添加了不同类型的紫外线吸收剂或者紫外线散射剂,也可以通过透光率曲线的形状进行简单区分。也对进口品牌和国产防晒霜的防晒效果进行了实验比较,结果显示只要是正规厂家的产品,国产防晒霜和进口防晒霜在防晒效果上并没有多大的差别。

SPF and PA index present the resistance ability of sunscreen to UVA （Ultraviolet A） and UVB （Ultraviolet B） re spectively. The present article focuses on the research on the relationship between ultraviolet transmittance and sunsereen ability based on definition of sunscreen efficiency and a simple and significant result was obtained by deducing. The technique we applied is spectral analysis dealing with ethanol-ethyl ether mixed solvent by ultraviolet and visible light speetrophotometer. We meas ured the UVA and UVB transmittance of 69 common sunscreen samples. The measurement result shows that spectral analysis method could differentiate sunscreens with different SPF and PA and identify whether the parameter value marked is accurate. So, an effective method is provided for the measurement of SPF and PA value. If different types of ultraviolet absorbent or UV scattering dose is added in sunscreen, the authors can distinguish them easily through the shape of the transmittance curve. In our sunscreen samples measured, domestic brands and imported brands are classified into two categories. By comparing the ex perimental results, the authors found that the domestic sunsereen and import sunscreen have no significant difference in sun block efficiency as long as the authors adopt the product of qualified manufacturer.