Carbon quantum dots (CQDs) co-doped with N, P and S derived from expired milk was prepared by a simple hydrothermal method. By dipping pure cotton face towel (PCFT) into CQDs ink, a flexible all-biomass CQDs/PCFT sensor was prepared for the first time. Due to the heteroatom doping, extremely small particle size of CQDs and excellent permeability of CQDs/PCFT film, the flexible CQDs/PCFT sensor showed the high sensitivity and bending stability. In the range of 0–60° bending states, the responses of CQDs/PCFT sensor to four target analytes changed by less 5.0%. After 3000 bending of 60°, the maximum change of the response to the target analytes was only 6.4%. Interestingly, due to the abundant functional groups and defects of CQDs, the flexible CQDs/PCFT sensor displayed sensing curves of different shapes for different target analytes. In this way, by establishing a database of sensing curves of target analytes, multiple analytes can be detected discriminatively by relying only on single sensor with the help of image recognition. This work provided a reference for the development of cotton fiber based all biomass flexible gas sensor.
Two new triterpenoid glycosides, 3α,19α,23α‐trihydroxy‐2‐oxo‐12‐ursen‐28‐O‐β‐d ‐glucopyranoside ( 1 ) and 3α,19α,23α‐trihydroxy‐2‐oxoolean‐12‐en‐28‐O‐β‐d ‐glucopyranoside ( 2 ) as well as three known compounds, 2α,3α,19α‐trihydroxyolean‐12‐en‐28‐O‐β‐d ‐glucopyranoside ( 3 ), 2α,3α,19α,23‐tetrahydroxy‐12‐ursen‐28‐O‐β‐d ‐glucopyranoside ( 4 ), and 2α,3β,19α,23‐tetrahydroxyurs‐12‐en‐28‐oic acid ( 5 ) were isolated from 75% EtOH extract of Rosa cymosa. Their structures were elucidated by extensive spectroscopic methods. All the isolated compounds displayed moderate inhibitory activity against LPS‐induced NO production in macrophages. 相似文献
