Solvothermal synthesis of nitrogen-doped carbon quantum dots for the sensitive detection of azithromycin.

Carbon quantum dots are widely used in various drug detection applications because of their excellent photoluminescence properties. However, there are few reports about the detection of macrolide antibiotics. In this work, blue emitting nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by using a hydrothermal method, which exhibit the most prominent emission band at 464 nm at an excitation wavelength of 414 nm. And it was found that Cu2+alone or the macrolide antibiotic azithromycin had no significant effect on the fluorescence intensity of N-CQDs. Still, when the two were mixed, they quenched the fluorescence of N-CQDs. Based on this, a fluorescence assay for azithromycin were developed. The fluorescence of the mixture of N-CQDs and Cu2+showed good linearity with azithromycin (0.52-42.2µM) with a low detection limit of 0.52µM.

[The IR spectra of complexes of fiber containing amidoxime groups with Fe(III), Co(II), Ni(II), Cd(II) and Hg(II)].

By the reaction Fe3+, Co2+, Ni2+, Cd2+ and Hg2+ with fiber containing amidoxime groups modified polyacrylonitrile fiber (AOCF), a series of coordinate complexes-AOCF-Fe(III), AOCF-Co(II), AOCF-Ni(II), AOCF-Cd(II) and AOCF-Hg(II) were prepared in acid medium. The fibers containing amidoxime groups with and without metal ions were taken for FTIR in the range of 4000-400 cm(-1). Their major bonds were assigned and compared. The results showed that in all complexes some bands (vC-N, vC=N and vN-O) were strengthened and a certain shift to higher wave number took place in the FTIR spectra with 4-21 cm(-1) shifts observed. The amidoxime groups and metal ions were bonding with coordinated bond.