Spectroscopic Analysis Of A Sunscreen Product
Abstract:
In this lab, our concept is to find the extinction coefficient “ε” for a specific sunscreen with a sun protection factor (SPF), we are using brand: NO-AD SPF 15 for this experiment, our extension coefficient “ε” value is to be 482.04 cm2/g.
Objective:
Our objective with this experiment is to find the relation of sun block with the extension coefficient by measuring the absorbent rate of UV rays the sunscreen can absorb. And how it can absorb harmful waves that emit from the sun. Ultra Violet (UV) rays are harmful for the skin if person stays for too long in the sun. It can cause damage to the skin and may lead to cancer.
Also, to relate other sunscreens products to another, as band name price and how well do they do once exposed to the suns UV rays.
Theory:
As Beer’s Law indicates:
A= (ε) (l) (C)
Where is A is the Absorbance, is proportional to C, the concentration of solution, the higher the concentration the higher the absorbent. ‘A” is also proportional to (l), the length of tube used, the longer the tube, the more molecules in the solution can absorb rays , as they are subjected to more rays. The extinction coefficient (ε), used to calculate the efficiency of absorption, it differs from every compound.
A α C α l α ε
We will be using a 1 cm sample length, and as a sunscreen will be using grams per ml (g/ml)
Procedure:
Please refer to CH221 Laboratory Manual pages 30 – 34
Data:
We are using NO-AD SPF 15 sunscreen
Weight= 0.0237 g
And 50 ml of 95% Ethanol
Sunscreen per ml=0.0237/50 = 4.7 x 10-4 g/ml
Making the dilution
Tube mL Stock Sol mL 95% EtOCH Dilution Factor (g) sunscreen/mL
1 3.00 0.00 1 4.7 x 10-4
2 2.50 0.50 0.833 3.9 x 10-4
3 2.00 1.00 0.666 3.2 x 10-4
4...
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