Cephalexin hydrochloride

The effective removal of antibiotics and their combined pollutants is critical for both aquatic environment and human health.In this study, a lignin-based organic flocculant, PRL-VAc-DMC, was synthesized from the paper pulp reject, using vinyl acetate (VAc) and methacryloxyethyltrimethyl ammonium chloride (DMC) as the grafting monomers.Its effectiveness for multiple antibiotics (including amoxicillin, cefalexin, norfloxacin, ofloxacin, oxytetracycline, and chlortetracycline hydrochloride) and their combined pollutants were evaluated.The results revealed that PRL-VAc-DMC was most effective in removing tetracyclines, while exhibiting lower efficacy for β-lactams and quinolones.The high removal efficiency for tetracyclines was likely due to their strong hydrophobicity, together with that functional groups such as hydroxyl, carbonyl, and amide groups effectively promoted H-bonding and n-π* interactions with PRL-VAc-DMC.The coexistence of humic acid and Kaolin enhanced the removal of amoxicillin and oxytetracycline, primarily due to that the hydrogen bond donor-acceptor properties and n-π* interactions of amoxicillin and oxytetracycline facilitated their combination with the co-existing contaminants.For the combined pollutants, the dominant removal mechanisms were charge neutralization and sweeping-bridging interaction, driven by their strong neg. charge and large particle size.Addnl., π-π* interactions and H-bonding provided by the benzene rings and oxygen- and nitrogen-containing functional groups in the pollutants also facilitated their binding with the flocculant.This work provides new insights into the mechanisms involved in the removal of antibiotic combined pollutants from the perspective of the antibiotic structures.

Residual Tetracycline-like analogs antibiotics, including Chlortetracycline (CTC) and Tetracycline (TC), in food pose a significant threat to public health. A 3D Zn(II) coordination polymer, designated as [Zn₄(L)₄(H₂O)]·2(DMF)·4H₂O (CP 1), was successfully synthesized via the solvothermal method, utilizing 4,4'-(quinoxaline-2,3-diyl)dibenzoic acid (H₂L) as the organic ligand. This fluorescent material exhibits remarkable stability in maintaining its structure and fluorescence intensity across various aqueous environments and a broad pH range. Research on aqueous phase sensing indicates that CP 1 exhibits significant quenching efficiency for CTC and TC antibiotics (CTC: K_sv = 1.0478 × 10⁵ M^-1, TC: K_sv = 2.897 × 10⁴ M^-1) and low detection limits (CTC: 0.075 μM, TC: 0.27 μM). Notably, CP 1 exhibits superior anti-interference capabilities and excellent reusability in fluorescence sensing applications. When applied to the practical detection of CTC and TC in food samples (tap water, milk and honey), the recovery rates range from 90.0 % to 107.0 %, with relative standard deviations (RSD) falling within 0.5 % to 1.7 %. To further elucidate the underlying fluorescence quenching mechanism, a comprehensive analysis was conducted, combining experimental data, density functional theory (DFT) calculations, and Hirshfeld surfaces analysis. This comprehensive approach revealed that the fluorescence quenching observed during the sensing process is jointly attributed to fluorescence resonance energy transfer, internal filtration effect, photoinduced electron transfer, and hydrogen bonding interactions.