UHPLC-MS Method for the Analysis of the Molecular Adjuvant Sulfavant A

A fast and sensitive method that is based on Ultra High Performance Liquid Chromatography coupled with High Resolution Mass Spectrometry (UHPLC-HRMS) for the measurement of Sulfavant A, a molecular adjuvant with a sulfolipid skeleton, is described. The method has been validated over the linearity range of 2.5–2000 ngmL−1 using a deuterated derivative (d70-Sulfavant A) as internal standard. Chromatographic separation is based on a UHPLC Kinetex® 2.6 µm PS C18 column and a gradient of methanol in 0.32 mM ammonium hydroxide solution buffered at pH 8. The lowest limit of quantification of Sulfavant A was 6.5 ngmL−1. The analytical procedure was tested on an extract of mice lung spiked with 30, 300, and 1500 ng of Sulfavant A. The analysis revealed a precision and accuracy value (as a mean value of all the quality control samples analyzed) of 4.7% and 96% in MeOH and 6.4% and 93.4% in the lung extracts, respectively.

Synthesis of Self-colored Thermal Stabilized Acrylonitrile/Itaconic Copolymers

Acrylonitrile (AN) was copolymerized with itaconic acid metal complexes [Co(II),Ni(II),Cu(II)] aiming to synthetize self-colored acrylonitrile fiber. The copolymerization occurred in water at 60°C using sodium bisulfite and potassium persulfate as redox initiators. The resulting copolymers are colored and exhibited high thermal stability as shown from their TGA curves. The investigated copolymers exhibited comparable thermal stability as that of PAN. The AN/ itaconic acid Co(NO3)2copolymer was considerably the most thermal stable copolymer while that of Ni(II) copolymer was the less stable one. Cu(II) copolymer showed an intermediate stability. The data also revealed that the maximum degradation occurred after 300°C (the cyclization temperature). Thus, neither the copolymerization nor the complexation affected the nitrile oligomerization reaction. The effect of adding ammonium hydroxide solution to acrylonitrile – itaconic acid copper(II) complex copolymer on the thermal stability of copolymer was also studied.

Effect of various amount of ammonium hydroxide on morphology of silica nanoparticles grown by sol-gel

Silica nanoparticles have drawn significant intentions for their potential in solar cell coating applications. These products occupy a noticeable position in a scientific research because of their easy preparation and wide uses for different technological applications. The quality of silica nanoparticles are highly dependent on the size. This study reports the synthesis of monodisperse silica nanoparticles by hydrolysis of tetraethyl orthosilicate (TEOS) in a mixture of ethanol and DI water as a solvent and ammonium hydroxide solution (NH4OH) as a catalyst. The solutions are stirred overnight and dried in a low-pressure furnace under 100 mbar for 3 hours at 60°C. Various-sized silica nanoparticles in the range 80 nm – 250 nm were examined under field emission scanning electron microscopy (FESEM). With the increasing volume of ammonia solution, an increase in the size of silica nanoparticles were observed.

Copper recovery from chalcopyrite flotation plant tailings acid leach using ion exchange resin dowtm XUS 43578.00

This study examined the feasibility of recovering copper from a sulphuric acid leach solution of chalcopyrite flotation plant tailings assaying 0.18 % copper and 0.19 % zinc using DOWTM XUS 43578.00 ion exchange resin. Zn2+cations are counter ionsto Cu2+cations during the ion exchange process. Adsorption and desorption tests were conducted on the resin with a leach solution containing26 mg Cu/L and 225 mg Zn/L,under various conditions of pH, DOWTM XUS 43578.00resin dosage, agitation time and eluant(ammonium hydroxide solution) concentration. The DOWTM XUS 43578.00resindemonstrated a high selectivity for copper over zinc, with a separation factor of 30.26 mg/g. The highcopper distribution coefficient of65L2/g2suggeststhe resin can effectively concentrate copper in leach solutions of these particular tailings.A 4M ammonium hydroxide solution yielded the highest copper recoveryat pH 3and0.6gresin dosageafter3hours of agitation. These results can be improved by a pre-treatment step to remove the zinc before the copper ion exchange process, and modifying the experiments to simulate industrial practice by having multi-stage sorption and desorption phases.