We have used the relative quantification of this radical in the same sample of skin before and after application of sunscreens to estimate the level of protection against UVA radiation provided by three popular sunscreens that say they have UV protection, over a range of densities applied. Keep up on the field with thought-provoking pieces from Sen. Marco Rubio. RESULTS: Validation of the method.-irradiated with UV skin recognizable (ESR) spectrum of the ascorbate radical, which was produced or undetectable, or detectable at very low levels in non irradiated skin. In contrast to previous reports, the radical ascorbate was not consistently detected in the skin not radiated in our experiments. This may be because the skin in our experiments was protected completely from the light in the room, that were thought previously to have a small effect on the signal of the radical, or may have reflected the use in our experiments in samples of fresh skin instead of frozen samples. The radicals formed in the only sunscreen do not interfere with radical ascorbate levels of application of until close to 4 mg / cm2; However, with much greater than this application (? 10 mg per cm2), radical production in the filter itself only became noticeable. The ascorbate radical is detected immediately in the irradiated skin and responds quickly to changes in radiation levels as shown in Fig. 2 (c), being restored to original levels after you close and reopen the Rainbow lamp.
Over the entire period of UV irradiation (up to 1400 seconds) ascorbate depletion is very light. The signal of the ascorbate radical decreased very slowly with irradiation prolonged (when he was studied over a period of approx. 30 min); However the rate of decrease varies according to the storage time of the skin prior to experimentation. Skin studied immediately after removing it from the patient exhibited levels very low ascorbate depletion and UV-induced depletion rates were increased with storage, becoming significant after 3 days of refrigeration.