Environmental behavior of 12 UV filters and photocatalytic profile of ethyl-4-aminobenzoate

Adela Jing Li, Ziye Sang, Chi Hang Chow, Japhet Cheuk Fung Law, Ying Guo, Kelvin S Y Leung*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

32 Citations (Scopus)


Ethyl-4-aminobenzoate (Et-PABA) is currently used as a substitute for 4-aminobenzoate (PABA) in sunscreens and anesthetic ointments. Despite its widespread use and hydrophilicity, Et-PABA has never been found in environmental waters. This study, probed the occurrence of Et-PABA in both seawater and drinking water sources in Hong Kong, and evaluated its transformation products (TPs) and environmental fate via cumulative potency and photocatalytic profile analyses. Another 11 UV filters used in skin-care products were also studied. Et-PABA was not detected in any water sample. Four other UV filters were dominant at ng/L level in both seawater and drinking water sources. UHPLC-QTOF-MS was used to elucidate the structure of TPs. With high resolution accurate mass data and fragment rationalization, 11 Et-PABA TPs were characterized, including seven intermediates firstly proposed as TPs; two compounds were reported for the first time. It is proposed that photocatalysis induces transformation pathways of (de)hydroxylation, demethylation and molecular rearrangement. Luminescent bacteria tests showed decreasing toxicity with increasing irradiation of Et-PABA, suggesting that irradiation TPs are less toxic than the parent compound. Transformation of Et-PABA appears to explain why Et-PABA has not been detected in the natural environment.

Original languageEnglish
Pages (from-to)115-125
Number of pages11
JournalJournal of Hazardous Materials
Publication statusPublished - 5 Sept 2017

Scopus Subject Areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Environmental occurrence
  • Ethyl-4-aminobenzoate
  • Photocatalysis
  • Transformation products
  • Triolein-SPMD


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