In this paper, carboxylated carbon nitride nanoparticles (carboxylated-g-C3N4NPs) were prepared through a one-step molten salts method. The synthesized material was characterized by transmission electron microscope (TEM), Fourier transform-infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS), etc. An electrochemical sensor based on single-stranded oligonucleotide/carboxylated-g-C3N4/chitosan/glassy carbon electrode (ssDNA/carboxylated-g-C3N4/chitosan/GCE) was constructed for determination of the hydroxyl radical (•OH), and methylene blue (MB) was used as a signal molecule. The sensor showed a suitable electrochemical response toward•OH from 4.06 to 122.79 fM with a detection limit of 1.35 fM. The selectivity, reproducibility, and stability were also presented. Application of the sensor to real meat samples (i.e., pork, chicken, shrimp, and sausage) was performed, and the results indicated the proposed method could be used to detect•OH in practical samples. The proposed sensor holds a great promise to be applied in the fields of food safety.Keywords:carboxylated-g-C3N4NPs;hydroxyl radical;electrochemical sensor;food safety
Haiyan Wang,Chunling Qi,Wenhuan He,Minghui Wang,Wenjing Jiang,Huanshun Yin,Shiyun Ai
A novel, simple and sensitive photoelectrochemical (PEC) immunosensing platform was constructed for detecting N 6 -methyladenosine (m 6 A) based on the carboxylated CN and avidin functionalized [email protected] 2 (ARS) nanocomposite . Herein, the N 6 -methyladenosine-5′-triphosphate (m 6 ATP) was selected as the detection target molecule, m 6 A antibody was used as recognition unit for m 6 A, the carboxylated g-C 3 N 4 (CN) was not only used as the photoactive substance, but the substrate for the m 6 A antibody immobilization , ARS was synthesized and used as signal amplification unit to improve the photocurrent of CN, Phos-tag-biotin was employed as bridge of m 6 ATP and [email protected] 2 through the specific interaction between phosphate group of m 6 ATP and Phos-tag, biotin and avidin, respectively. Under the optimal condition, the fabricated PEC biosensor showed a linear range of 0.01–10 nM and high detection sensitivity with low detection limit of 3.23 pM for m 6 ATP. Besides, the developed strategy was also successfully applied to evaluate the content of m 6 A in human serum samples.