# A prompt technique to identify fluoroquinolone antibiotics (FQs) residue in the environments

## TL;DR

This paper introduces a new fluorescence-based method to detect and quantify fluoroquinolone antibiotics in the environment, even when mixed with other substances.

## Contribution

A novel spectral technique is developed to distinguish and quantify fluoroquinolones in environmental samples using fluorescence spectroscopy.

## Key findings

- Fluoroquinolones can be identified using fluorophores at 225–230/285–295 nm in EEM and PARAFAC models.
- Fluoroquinolones show distinct spectral signatures at 275 nm excitation with <350 nm emission, differentiating them from humic substances.
- Combining fluorophore intensity at specific wavelengths allows quantification of minimal fluoroquinolone residues in environmental samples.

## Abstract

The widely used fluoroquinolone (FQ) antibiotics have become emerging contaminants due to their unconstrained usage. A prompt, straightforward, précised, and advanced technique named fluorescence spectroscopy was applied to characterize and semi-quantify FQs. However, excitation wavelengths on the comparable ranges of FQs and ubiquitous humic substance (HS) complicate their identification in the mixture. This study develops a simple spectral technique that affirms the individual identification of FQs and HS in the natural environment. The following characteristics and methods can demonstrate the traces of FQs in the environment-•Presence of fluorophore at Excitation/Emission = 225–230/285–295 nm wavelength in excitation-emission matrix (EEM) and parallel factor analysis (PARAFAC) models.•FQs and HS have fluorophores at excitation wavelengths of 275 nm and 325 nm in PARAFAC analysis. Unlike HS, the notable spectral presence in <350 nm emission during 275 nm excitation in FQs ensures their distinct identification in the mixture.•FQ affirming component intensity at Excitation/Emission = 225–230/285–295 nm and the intensity <350 nm emission during 275 nm excitation are considered in conjunction to quantify the amount of least FQ in any environmental sample.

Presence of fluorophore at Excitation/Emission = 225–230/285–295 nm wavelength in excitation-emission matrix (EEM) and parallel factor analysis (PARAFAC) models.

FQs and HS have fluorophores at excitation wavelengths of 275 nm and 325 nm in PARAFAC analysis. Unlike HS, the notable spectral presence in <350 nm emission during 275 nm excitation in FQs ensures their distinct identification in the mixture.

FQ affirming component intensity at Excitation/Emission = 225–230/285–295 nm and the intensity <350 nm emission during 275 nm excitation are considered in conjunction to quantify the amount of least FQ in any environmental sample.

Image, graphical abstract