Liu Zhang,Yue Hou,Congcong Lv,Wei Liu,Zixuan Zhang,Xing Peng
In this work, copper(II)-containing metal–organic xerogels (Cu-MOXs), which were composed of copper as the central ion and 2,2′-bipyridine-6,6′-dicarboxylic acid as the ligand, were quickly synthesized by a mild facile strategy. The Cu-MOXs exhibited superior catalytic performance for the luminol–H2O2 chemiluminescence (CL) system. The possible mechanism was studied via CL spectra, UV-Vis absorption and electron paramagnetic resonance (ESR). Since dopamine (DA) can inhibit the reaction of this system, a sensitive paper-based CL device for the detection of DA was established. Under the optimal experimental conditions, the linear range of this method was 40–200 nM with a detection limit of 10 nM. The proposed method was used for the determination of DA in urine samples.
Herein, a multi-use strategy was initiated for visual point-of-care tests, adulteration identification, removal and recycling of dyes in both environmental and food samples using hydrophobic deep-eutectic solvent (HDES)-coated paper as an all-in-one device. HDES, which composed by decylic acid and tetraoctylammonium bromide, was prepared as a sorbent for dyes, then paper devices were facilely fabricated by coating HDES onto printing papers. Due to the coexistence of carbon chains, carboxyl and quaternary ammonium groups, HDES-mediated dyes extraction was of fine versatility through electrostatic interaction and hydrophobic effect, by which the recycling rate of dyes reached 96.5 % at only 5 min of extraction time. Colorimetry of dyes in simulated dye effluents and drinks could be ended as fast as 10 s with LODs at 10 −3 mg/mL level, and the colorimetric results were highly agreed with those generated by instrumental techniques and smartphone-based image analysis. Identifications of fruit/vegetable juices and chili oil adulterated with the same-color artificial dyes were also realized in a single paper strip, giving an identification capacity low as to 1.5 × 10 −3 mg/mL. The success of these cases enlightens a new direction for HDES-based multi-purpose application.
Excess exposure to a high environmental level of nickel can cause serious harm to human health. Therefore, it is particularly necessary to develop a low-cost, fast and sensitive method for nickel assay. In this paper, novel counting-based microfluidic paper-based devices (μPADs) were prepared by hand drawing and yellow oily double-sided adhesive tape. The dissolved adhesive tape was used for the first time to make the hydrophobic “ink”. The marker filled with the “ink” drew the desirable layout on paper followed by a drying process. The μPADs were constituted of one circular sample introduction zone (diameter 4.5 mm) and four circular detection zones (diameter 3 mm). The adjoining detection zones were connected by a strip channel (1.2 mm × 2 mm). The fabrication conditions were optimized and the barriers created with the marker revealed good reproducibility. The analytical performance of the developed devices was investigated for nickel assay. The Ni2+ standard was added to the sample introduction zone, and subsequently moved into the detection zones containing dimethylglyoxime (DMG), where it reacted with Ni2+ and formed a reddish pink Ni–DMG complex. Through counting the number of colored dots, the developed μPADs realized the semi-quantitative analysis of nickel. More importantly, the fabrication of the developed counting-based μPADs only used a marker and adhesive tape, possessing the advantages of instrument-free simplicity and low cost. Our method has great potential for enabling μPADs to be easily implemented in laboratories or research centers with limited resources.
危险品化学品经营许可证（带存储）