Amoxicillin is one of the most important semi-synthetic penicillin broad-spectrum β-lactam antibiotics and has achieved many applications. There are few reports on its application for synthesizing carbon dots (CDs). Present work explored the possibility of amoxicillin converted into CDs with sodium carbonate used as the co-reactant employing facile hydrothermal method. The obtained CDs exhibited good selectivity and sensitivity to benzidine and could be explored as an effective fluorescence probe for monitoring benzidine. The fluorescence intensity of CDs was quenched based on the principle of static quenching due to the formation of a non-fluorescent complex between CD and benzidine. Within the range of 0.2–2 μM and 2–16 μM, CDs possessed good linear characteristics, high sensitivity, and a low detection limit of 0.08 μM. The results demonstrated that the fluorescence probe possessed the merits of simplicity, rapidity, low cost, short analytical time, high selectivity and sensitivity, and good stability. According to the verification results from the real water samples, the fluorescence probe had high reliability and feasibility, and could be employed for monitoring benzidine in waters.
Butachlor is an effective herbicide to deal with undesired weeds selectively and is used at high levels in Asian countries. However, its interaction and impairment effect on BSA was still not clear. In this study, we investigated the interaction between butachlor and bovine serum albumin (BSA) by multi-spectroscopic methods including UV absorption , circular dichroism (CD) spectra, Fourier transform infrared (FTIR) spectra and fluorescence spectra under physiological conditions (pH = 7.4). The results revealed that there was a static quenching of BSA induced by butachlor stemmed from the formation of complex. Based on thermodynamic data, the interaction of butachlor with BSA was due to happen, and van der Waals force as well as hydrogen bond were the major forces contributed to the interaction. The binding constant K b and number of binding site of butachlor with BSA were 5.158 × 10 5 and 1.372 at 303 K, respectively. The distance r between donor (BSA) and acceptor (butachlor) was 0.113 nm, obtained according to the Förster theory. The results revealed that butachlor induced conformational changes in BSA but the secondary structure of BSA was still retained. In addition, the microenvironment around chromophore residues of BSA, for example, tryptophan , changed as well, resulting from the formation of more hydrogen bonds.
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