Abstract:
Rationale. Certain antibiotics have been repurposed for the management of infected COVID-19
cases, because of their possible effect against the virus, and treatment of co-existing bacterial
infection. The consumption of these antibiotics leads to their access to sewage, industrial and
hospital effluents, then to environmental waters. This creates a need for the routine analysis and
treatment of water resources. Methodology. Detection and quantitation of three repurposed
antibiotics: levofloxacin (LEVO), azithromycin (AZI) and ceftriaxone (CEF) were studied in different
water samples using LC-MS/MS methods employing a C18 column and a mobile phase consisting of
80% acetonitrile/20% (0.1% formic acid in water) after solid phase extraction on Oasis HLB Prime
cartridges. Real water samples were treated with synthesised graphitic carbon nitride (g-C3N4) to
remove the three types of antibiotics from contaminated water under experimental conditions
optimised by response surface methodology, using Box–Behnken experimental design. Results. The
analytical method was validated in the concentration range of 10–5000 ng mL–1 for the three drugs.
The removal percentages were found to be 92.55, 98.48 and 99.10% for LEVO, AZI and CEF,
respectively, using synthesised g-C3N4. Discussion. The analytical method was used for the
estimation of the three cited drugs before and after their removal. The method was assessed
using ComplexGAPI as a greenness tool and the RGB 12 algorithm as a whiteness model. The
method was applied for the analysis and treatment of real water samples before and after their
treatment. It proved to be simple, low-cost and environmentally sustainable.
