A method for evaluating the ultraviolet protection ability of granular physical sunscreens
A technology of physical sunscreen agent and evaluation method, which can be applied in the field of UV absorbance measurement of particle-type physical sunscreen agent, can solve the problems of unclear comparison, difference in results, difficulty in accurate quantification, etc. Easy to quantify effect
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Embodiment 1
[0023] Embodiment one: prepare 1% TiO 2 Suspension, after stirring evenly, take 0.1g and disperse in 9.9g of 1% Na 2 CO 3 Dilute solution, then add 10g of 0.3% carbomer 980 solution that has been swollen while stirring to obtain TiO with a concentration of 0.005%. 2 Solution, measure its absorbance in the 200-400nm wavelength range, the result is as follows figure 1 shown.
[0024] figure 1 Among them, curve 1 is the ultraviolet absorbance measurement result taking distilled water as contrast; Curve 2 is the ultraviolet absorbance taking distilled water as contrast dispersion medium; absorbance); the dotted line 4 is the result of subtracting curve 2 from curve 1, indicating that the absorption after eliminating the absorption of the dispersion medium should be TiO 2 own UV absorbance. Curve 3 and dotted line 4 almost overlap, indicating that the absorbance of the solution is the sum of the absorbance of each substance in the solution, and the absorbance measured with th...
Embodiment 2
[0025] Embodiment two: prepare the ZnO suspension of 5%, after stirring evenly, get the 2% Na that 0.1g is dispersed in 9.9g 2 CO 3 Dilute solution, then add 10g of swelled 0.3% Carbomer 980 solution while stirring to obtain a ZnO solution with a concentration of 0.025%, measure its absorbance in the 200-400nm wavelength range, the results are as follows figure 2 shown.
[0026] figure 2 The measuring method of each line in the above is the same as that in Example 1, and the curve 3 and the dotted line 4 also almost overlap, indicating that the absorbance of the solution is the sum of the absorbance of each substance in the solution, and the absorbance measured with the dispersion medium as a contrast is the ZnO itself. Absorbance.
Embodiment 3
[0027] Example 3: According to the method of Example 1, a series of TiO with concentrations of 0.005%, 0.010%, 0.015%, 0.020%, and 0.025% were prepared 2 Solution, concentration of 0.015%, 0.020%, 0.025%, 0.030% series ZnO solution, respectively measure their absorbance. The result is as image 3 , 4 As shown, it can be seen that the shape of each line in each figure is the same, and only the absorbance value increases with the change of concentration. Because of TiO 2 There is little difference in the absorbance values of ZnO and ZnO in the entire ultraviolet region, so the average absorbance at different wavelengths is taken, and the TiO 2 and the relationship between ZnO concentration and absorbance, such as Figure 5 shown. TiO 2 The multiple correlation coefficient of r 2 0.961 for ZnO and 0.998 for ZnO, indicating a good linear correlation between concentration and absorbance.
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