Organic Ion-Associate Phase Microextraction/Back-Microextraction for Preconcentration: Determination of Nickel in Environmental Water Using 2-Thenoyltrifluoroacetone via GF-AAS

An ion-associate phase (IAP) microextraction/ back-microextraction system was applied for the enrichment, separation, and detection of trace amounts of nickel from environmental water samples. Thenoyltrifluoroacetone (HTTA) acted not only as a chelating reagent for nickel, but also as a component of the extraction phase, i.e., IAP. Nickel in a 40 mL sample solution was pH-adjusted with phenolsulfonate (PS−) and tetramethylammonium hydroxide and converted by chelation reaction in the presence of thenoyltrifluoroacetonate (TTA−). When benzyldodecyldimethylammonium ion (C12BzDMA+) was added, a suspension of IAP formed in the solution. The IAP consisted of TTA−, a chelating reagent, the PS−, a component of pH buffer, and C12BzDMA+, which helps extract the chelating complex. When the solution was centrifuged, the IAP separated from the suspension and the nickel-TTA chelate was extracted into the bottom phase of the centrifuge tube. After the aqueous phase was taken away, 100 µL of nitric acid (2 M) solution containing phosphate was used to back-microextract nickel from the IAP. The acid phase was measured via graphite-furnace atomic-absorption spectrometry (GF-AAS). The proposed method facilitated a 400-fold enrichment. The limit of detection was 0.02 µg L−1. The proposed method was applied for the determination of nickel in river water and seawater samples.

Sensing application of novel nanocomposite based on lanthanide functionalized nanoporous material and polymer matrix

Recently, lanthanide hybrid material has aroused great interest because of its wide range application in lighting material, bio-imaging, chemical/biological sensing and so on. Here, a binary lanthanide terbium/mesoporous silica hybrid material (Tb@MCM-41), and a ternary lanthanide terbium/mesoporous silica/polyurethane hybrid material (Tb@MCM-41@PU) are reported. Typically, the lanthanide Tb3+ ions were connected onto the surface of mesoporous MCM-41 via the molecular bridge built by the synergy of silane coupling agent (APTEOS) and chelating reagent (DTPA), and then the resulted Tb@MCM-41 was encapsulated into a commercial polymer matrix (PU) to form Tb@MCM-41@PU composite film. The sensing experiments conducted in solution had proven that Tb@MCM-41 has good selective sensing ability to the dopamine molecular. And further experiments also indicated the Tb@MCM-41@PU composite film can be used as a very convenient sensor tool towards dopamine.

Enhanced recovery of CD9-positive extracellular vesicles from human specimens by chelating reagent

Extracellular vesicles (EVs) have gained attention as potential targets of early diagnostics and prognosis in the field of liquid biopsy. Despite clinical potentials, the best method to isolate EVs from specimens remains controversial due to low purity, low specificity, and lack of reproducibility with current isolation methods. Here we show that a chelating reagent enhances the recovery efficiency of EVs from crude biological samples by immunoprecipitation using an anti-CD9 antibody. Proteomic and western blotting analyses show that the EVs isolated using the chelating reagent contain a wider variety of proteins than those isolated with PBS.

A New Chelating Reagent: Its Synthesis/Characterization and Application for the Determination of Cd(II) and Ni(II) in Various Food and Make-Up Product Samples by FAAS Using Simultaneous Microextraction Sampling

A new and simple dispersive liquid–liquid simultaneous microextraction procedure was developed for the rapid separation and simultaneous extraction/preconcentration of Cd(II) and Ni(II) at ultratrace amounts. Microextraction of the analytes was carried out in the presence of 2-methyl-5-[(Z)-pyridin-4-yldiazenyl]quinolin-8-ol as the chelating reagent. Chloroform and ethanol were used as the extraction and dispersive solvents. Various parameters that influence the microextraction procedure's efficiency—such as pH, centrifugation rate and time, reagent concentration, and sampling volume on the recovery of analytes—were examined. The calibration curves were linear in the range of 0.01–1.25 and 0.075–5 mg/L with LODs of 0.25 and 0.84 μg/L, and with a preconcentration factor of 94, for Cd(II) and Ni(II), respectively. Precision was >1.0%. The accuracy of the method was confirmed by analyzing the Certified Standard Reference Material (CWW-TMD: Certified wastewater-Trace metals, wastewater). The results show that the dispersive liquid–liquid simultaneous microextraction pretreatment is a sensitive, rapid, simple, green, and safe method for the separation/preconcentration of cadmium and nickel.

Application of Chelating Collectors in the Flotation of Copper Minerals

The application of new chelating reagents on the flotation of copper minerals has been paid much attention in recent years. These collectors have successfully extracted the copper minerals from the low-grade refractory ores, and one of the most important collectors is the alkylhydroxamate-based chelating reagent which shows the excellent flotation performance to the copper oxide minerals. Furthermore, the mixture of various chelating reagents can recover the copper sulfides and oxides simultaneously from the complicated copper ores, which is attributed to the synergy among collectors. Thus we conclude that it is an important flotation method by using chelating collectors in conjunction with other traditional collectors, by which the synergy can break through the limitation of single reagent and enhance the flotation efficiency.

Flotation Responce of the Refractory Yangla Copper Oxide Ores with Hydroxamate Collectors

To establish the flotation response and suitability of the collectors, series of bench-scale flotation tests are conducted for the refractory oxide copper ores obtained from Yangla Mine in Yunnan province. A simple xanthate (PAX) is used as the sulphide collector and a chelating reagent of hydroxamate AM28 as the oxide collector. It is found and confirmed by mineralogical examination that AM28 successfully recovered all the discrete copper oxide minerals from the Yangla ore. The flotation tests show that the overall copper recovery is affected due to the minerals copper associated with goethite which is not amenable to flotation. The average copper recovery from the rougher tests is 38.4% with a concentrate grade of 3.19%. The additional cleaning flotation can increase the Cu grade in concentrate further.