The stability of ascorbate in refrigeration storage was verified by measurement of the signal strength of the ascorbate radical in different samples of the same fragment of skin at different storage in cooling (0.1 to 3 days) as shown in Fig. 2 (d). The average of the intensity of the signal is slightly lower a day after cutting compared with the recorded immediately after cutting, but is largely comparable, reflecting similar levels of ascorbate in the skin. Day 3 after the cutting the signal strength of the ascorbate radical average is significantly lower than being about half that after cutting, and thus ascorbate levels are depleted to day 3. Therefore, whereas every effort was made to use skin samples as soon as it was feasible after cutting, a cutting of 24-hour period was chosen. QUANTIFICATION of the protection offered by filters plots with high FPS: Fig. 3 shows the typical spectrum obtained before and after the solar filter is applied to the skin of the chest.
These data are typical of those used for subsequent quantitative analysis of the protection provided by sunscreens high FPS. Usually there was only a small observable reduction (less than 50%) in the intensity of the signal of the ascorbate radical compared to unprotected skin. This reduction appears to rise approximately to 2 mg per cm2, with very little reduction with higher levels of application. Fig. 4 shows the percentage reduction in the intensity of the signal of the radical ascorbate (taken at the height of the relative field of absorption at the midpoint of the spectrum) to different applications of sunscreens high FPS. The density of the application was calculated as weight measured solar filters applied on the top of the slide of silica plane relative to the extent of the arc of the skin and not deformed of the cellular tissue. The percentage reduction in the intensity of the signal is similar for all 3 brands studied and increases with the application up to approx.