Trace determination of parabens in cosmetics and personal care products using fabric‐phase sorptive extraction and high‐performance liquid chromatography with UV detection

A simple, fast, and sensitive analytical protocol using fabric‐phase sorptive extraction followed by high performance liquid chromatography with ultraviolet detection has been developed and validated for the extraction of five parabens including methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben. In the present work, sol‐gel polyethylene glycol coated fabric‐phase sorptive extraction membrane is used for the preconcentration of parabens (polar) from complex matrices. The use of fabric‐phase sorptive extraction membrane provides a high surface area which offers high sorbent loading, shortened equilibrium time, and overall decrease in the sample preparation time. Various factors affecting the performance of fabric‐phase sorptive extraction, including extraction time, eluting solvent, elution time, and pH of the sample matrix, were optimized. Separation was performed using a mobile phase consisting of water:acetonitrile (63:37; v/v) at an isocratic elution mode at a flow rate of 0.9 mL/min with wavelength at 254 nm. The calibration curves of the target analytes were prepared with good correlation coefficient values (r² > 0.9955). The limit of detection values range from 0.252 to 0.580 ng/mL. Finally, the method was successfully applied to various cosmetics and personal care product samples such as rose water, deodorant, hair serum, and cream with extraction recoveries ranged between 88 and 122% with relative standard deviation <5%.     

ZIF‐8‐Nanocrystalline Zirconosilicate Integrated Porous Material for the Activation and Utilization of CO2 in Insertion Reactions

The conversion of CO₂ to useful chemicals, especially to atom economical products, is the best approach to utilize an excess of CO₂ present in the atmosphere. In this study, a metal‐organic framework (ZIF‐8) is integrated with nanocrystalline zirconosilicate zeolite to develop an integrated porous catalyst for CO₂ insertion reactions. The catalyst exhibits excellent activity for the CO₂ insertion reaction of epoxide to produce cyclic carbonate in neat condition without the addition of any co‐catalyst. The catalyst is stable and recyclable during the cyclic carbonate synthesis. Further, the catalyst also exhibits very good activity in another CO₂ insertion reaction to produce quinazoline‐2,4(1H, 3H)‐dione.     

Electrical Conductivity and Thermoelectric Power of Silver Iododichromate Fast Ion Conducting Electrolytes

Fast ion conducting solid electrolytes are becoming increasingly important owing to their application in solid state ionic devices. The present work deals with the silver ion conducting x AgI – (1–x)Ag₂Cr₂O₇ electrolyte system. These electrolytes have been characterised by X-ray diffraction, electrical conductivity, electronic conductivity and thermoelectric power techniques. A high ionic conductivity of the order of 10⁻³ S/cm has been observed for the composition mol% 80 AgI–20 Ag₂Cr₂O₇, at room temperature. The electronic conductivity of this electrolyte is three orders of magnitude lower than the ionic conductivity.     

Restoration optimization strategy for multifiber optical networks

Resource optimization is a very important issue related with restoration in optical networks. In the proactive restoration, backup lightpaths are established along with the primary light paths. In this paper, we have proposed a strategy for resource optimization, which works with proactive restoration. The performance of the proposed strategy is evaluated by applying on the sample network.     

Photoluminescence properties of Gd:ZnO nano phosphor

Journal of Sol-Gel Science and Technology - Gd (0.1, 0.5, 1.0?mol%) doped ZnO nano phosphor, prepared by wet chemical method followed by sintering in air at 700?°C, was...     

Michael reaction of ketones and β-nitrostyrenes catalyzed by camphor-10-sulfonamide-based prolinamide

Novel camphor sulfonamide based organocatalysts were evaluated for their catalytic activity in the Michael reaction of ketones with nitroolefins. Reaction of ketones with β-nitrostyrenes in the presence of 20 mol % organocatalyst 1a and benzoic acid under solvent-free conditions at 0 °C provided the desired Michael adducts with high chemical yields (up to 97%) and excellent stereoselectivities (>99:1).     

Reduction of CO2 by nickel (II) macrocycle catalyst at HMDE

With the aim of finding a suitable electrocatalyst for the efficient reduction of carbon dioxide, the electrochemistry of nickel (II) complex of 1,3,6,9,11,14-hexaazatricyclo [12·2·1·1] octadecane was studied using cyclic voltammetry (CV) and controlled-potential electrolysis (CPE) techniques in the presence and absence of CO₂ in 100% H₂O, CH₃CN-H₂O mixtures (20–100%) and DMF-H₂O (70–100%) mixtures. The efficiency of this process is determined using the coulometry technique. CO is the major product in the gaseous phase and HCOOH the sole product formed in the solution phase.     

Multiple scattering of gamma rays in water,concrete and sand

The transmitted photon spectra of¹³³Ba,²²Na,¹³⁷Cs,⁵⁴Mn and⁶⁰Co point sources are measured through different thicknesses of water, concrete and sand. The multiple-scatter peaks observed in these materials at 60, 90 and 100 keV energies respectively are found to be independent of incident photon energy and thickness of the medium.