Date of Award


Document Type

Union College Only

Degree Name

Bachelor of Science



First Advisor

Laura MacManus-Spencer




sunscreen, ultraviolet, photochemical, degradation, toxicity


Ultraviolet filter chemicals (UVFCs) are used in sunscreen products to protect skin from the sun’s harmful ultraviolet rays. Entering through direct and indirect inputs, UVFCs have been detected in water bodies and biota, raising inquiry into their environmental fate and toxicity. A commonly used UVFC is octyl dimethyl para-aminobenzoic acid (OD-PABA), which attenuates the sun’s rays but has shown susceptibility to photodegradation. Its photochemical instability results in the formation of numerous degradation products. Currently, two de-methylated products and one methylated product have been identified, along with evidence of possible dimerization and the possible formation of para-aminobenzoic acid (PABA). Methods have been developed to separate and isolate the degradation products from a photolysis mixture by high performance liquid chromatography and thin layer chromatography. The structures of these degradation products have been investigated by nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry. The cellular toxicity of OD-PABA and PABA has been investigated. Understanding the environmental fate and toxicity of OD-PABA and its photodegradation products will lead to more informed decisions about its use and regulation in sunscreens.