A colorimetric assay for measuring iodide using Au@Ag core-shell nanoparticles coupled with Cu(2+).

Au@Ag core-shell nanoparticles (NPs) were synthesized and coupled with copper ion (Cu(2+)) for the colorimetric sensing of iodide ion (I(-)). This assay relies on the fact that the absorption spectra and the color of metallic core-shell NPs are sensitive to their chemical ingredient and dimensional core-to-shell ratio. When I(-) was added to the Au@Ag core-shell NPs-Cu(2+) system/solution, Cu(2+) can oxidize I(-) into iodine (I2), which can further oxidize silver shells to form silver iodide (AgI).

A simple, rapid and eco-friendly approach for the analysis of aromatic amines in environmental water using single-drop microextraction-gas chromatography.

Single-drop microextraction (SDME) coupled with gas chromatography-flame ionization detector (GC-FID) was developed for the extraction and determination of aromatic amines (AAs) in environmental water samples. A silicon tube was introduced for the SDME procedure by inserting it into the needle of the micro-injector. In this manner, a large volume of extractant is allowed to be suspended for the extraction, leading to the enhancement of method sensitivity and reproducibility.

Beta-MnO2 3D nanostructures: mineralizer-assisted synthesis, characterization, and growth mechanism.

The beta-MnO2 three-dimensional (3D) nanostructures were synthesized in large area by a mineralizer-assisted hydrothermal route. KNO3 was introduced as inorganic mineralizer to direct the growth of beta-MnO2 3D nanostructures from Mn(NO3)2 solutions. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM).

'Green' synthesis of nitro alcohols catalyzed by solid-supported tributylammonium chloride in aqueous medium.

A series of 1-aryl-2-nitroalkan-1-ols (5a-m; Table 2) was prepared in yields of 64-94% by Henry reaction between aromatic aldehydes and nitroalkanes in the presence of a dual catalytic system of KOH and polystyrene-supported tributylammonium chloride (PsTBAC; 2). The reactions were performed either in H2O containing 10% of THF or, in the case of liquid reagents (aldehydes and nitroalkanes), in neat H2O at room temperature. The immobilized phase-transfer catalyst, designed to be used for large-scale industrial processes, could be easily separated from the products, and effectively re-used several times, basically without loss in activity.