Detecting Quinolone Antibiotics in Urine

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In a new study published in the Journal of Chromatography A, scientists from the Huazhong University of Science and Technology in Wuhan, China have created a new method for analyzing quinolones in urine using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) (1). This was accomplished by synthesizing molecularly imprinted polymers (MIPs) using reflux precipitation polymerization (RPP) with a real template, which is the first time such an approach has been used.

A woman holding a urine sample in his hand | Image Credit: © Mediteraneo - stock.adobe.com

A woman holding a urine sample in his hand | Image Credit: © Mediteraneo - stock.adobe.com

Quinolones are a class of antibiotics typically used in anti-infectives and veterinary antimicrobials. These medications help fight against health issues including urinary tract infections, sexually transmitted infections, certain types of pneumonia, and more (2). However, prolonged exposure to quinolone antibiotics can have negative consequences; they can harm a fetus during pregnancy, negatively affecting human intestinal microbiota, and increase susceptibility to bacterial resistance. To better analyze quinolones in human cells, scientists are looking to urine collection, since they are usually excreted through the kidneys and are broadly present and stable in urine (1).

Various methods are used for quinolone detection, such as high-performance liquid chromatography with ultraviolet detection (HPLC-UV), gas chromatography-tandem mass spectrometry (GC-MS/MS), and, most notably, liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS/MS has been viewed as most effective due to its high sensitivity and specificity. Additionally, solid-phase extraction (SPE) based on molecularly imprinted polymers (MIPs) is widely used for selective extraction in this field. MIPs are known for having high selectivity, stability, and reusability, and are used as SPE adsorbents to extract quinolones from food, environmental, and biological samples. SPE performance usually relies on the MIP sorbents’ shapes and distribution, which can make rapid synthesis of MIPs with uniform particles an issue.

In previous studies, the scientists used reflux precipitation polymerization (RPP) to synthesize MIPs that selectively adsorb propranolol and methamphetamine. According to the scientists, “Compared with bulk polymerization, RPP is a simple approach for the synthesis of MIPs in a short synthesis time and with high synthesis efficiency” (1). This led to synthesizing MIPs for a group of quinolone antibiotics using RPP for the first time, specifically using ofloxacin as a template. The synthesized MIPs were evaluated for binding capacity and selectivity, which were then used as SPE adsorbents. Finally, LC-MS/MS was used to establish a method for the determination of five quinolones in urine.

The synthesized MIPs showed promising adsorption performance and selectivity towards the quinolones, which led to their use as SPE adsorbents. Following the experiment, the MIPs-SPEC-LC-MS/MS process showed good correlation (R2 ≥ 0.9961) in the linear range of 1–500 μg L−1. Additionally, the quinolones had a limit of detection (LOD) range of 0.10–0.14 μg L−1 and a limit of quantification (LOQ) range of 0.32–0.48 μg L−1. Notably, the method also displayed promising reproducibility (≤ 13 %) and high accuracy (92%–113%). These results bolstered the scientists’ belief in this method. “We are confident that this method holds significant promise for the analysis of quinolones within the contexts of forensic medicine, epidemiology, and environmental chemistry,” the scientists concluded (1).

References

(1) Wu, Y.; Xiong, J.; Wei, S.; Tian, L.; Shen, X.; Huang, C. Molecularly imprinted polymers by reflux precipitation polymerization for selective solid-phase extraction of quinolone antibiotics from urine. J. Chromatogr. A. 2024, 1714, 464550. DOI: https://doi.org/10.1016/j.chroma.2023.464550

(2) Yan, A.; Bryant, E. E. Quinolones. National Library of Medicine 2023. https://www.ncbi.nlm.nih.gov/books/NBK557777/ (accessed 2023-12-18)

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