Simultaneous Electrochemical Determination of Vitamin K1 and Vitamin D3 by using Poly (Alizarin Red S)/Multi-walled Carbon Nanotubes Modified Glassy Electrode

Background: The goal of this research is to develop a new electroanalytical procedure for the simultaneous electrochemical detection of vitamin K1 (VK1) and vitamin D3 (VD3), in a sodium dodecyl sulfate (SDS) -containing buffer solution, with no detectable interference of other kinds of vitamin A and vitamin E present in the sample solution. Surfactant solutions are well known their capability to dissolve oil-soluble substance such as dyes, hydrocarbons, esters, perfumes, and so on. Micellar solubilization is the powerful alternative for the dissolution of poorly soluble or hydrophobic compounds in aqueous environments. Surfactants micellar media can be successfully applied for the solubilization of lipophilic organic compounds in water media and enhancement of their electrochemical activity. In this research, the anionic surfactant SDS was used as the solubilizing agent

Electrochemical Determination of Dopamine Using a Graphene-Screen-Printed Carbon Electrode with Magnetic Solid-Phase Microextraction

A magnetically separable Fe3O4@Diaion HP-2MG composite was prepared using the coprecipitation method and the resulting magnetic Fe3O4@Diaion HP-2MG composites were used for the separation and preconcentration of trace amounts of dopamine. For the detection stage, square wave voltammetry on a disposable graphene-screen-printed carbon electrode was successfully used for the determination of dopamine. The graphene-screen-printed carbon electrode exhibited excellent electroanalytical performance for dopamine. The linear concentration range was from 0.8 to 80 mu M and a detection limit of 50nM for dopamine was obtained. In combination with the magnetic solid-phase extraction method, the sensor response was linearly proportional to the concentration of dopamine in the range of 0.01-6.0 mu M with a correlation coefficient of approximately 0.9992. The detection limit of the sensor was found to be 5.0nM by square wave voltammetry. The combined methodology was successfully applied to determine dopamine in urine samples with good recoveries ranging from 95 to 98%

Nanotechnology-based Colorimetric Approaches for Pathogenic Virus Sensing: A Review

Fast and inexpensive virus identification protocols are of paramount value to hinder the increase of pandemic diseases, minimize economic and social damages, and expedite proper clinical rehabilitation. Until now, various biosensors have been developed for the identification of pathogenic particles. But, they offer many limitations. Nanotechnology overcomes these difficulties and allows a direct identification of pathogenic species in real-time. Among them, nanomaterial based-colorimetric sensing approach for identifying pathogenic viruses by the naked eye has attracted much awareness because of their simplicity, speed, and low cost. In this review, the latest tendencies and advancements used in detecting pathogenic viruses using colorimetric concepts, are overviewed. We focus on and reconsider the use of distinctive nanomaterials such as metal nanoparticies, carbon nanotubes, graphene oxide, and conducting polymer for the formation of colorimetric pathogenic virus sensors

Ionic Liquid Based Dispersive Liquid-Liquid Microextraction Combined with Magnetic-Based Dispersive Micro-Solid-Phase Extraction for Determination of Trace Cobalt in Water Samples by FAAS

Background: Cobalt is one of the most important essential trace metals of human nutrition. Low doses of cobalt are needed for many humans and animals to stay healthy. Cobalamine (named vitamin B-12) is a cobalt-containing essential vitamin. The direct detection of metal ions in various matrices by AAS may be difficult due to matrix interferences and extremely low levels of metal ions. Thus, a preconcentration and separation step is normally demanded. In this report, a two-step microextraction technique, combining room temperature ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) and dispersive magnetic solid-phase microextraction (MSPME) was prepared for the flame atomic absorption spectrometric determination (FAAS) of trace cobalt ions in water samples

Electrochemical Determination of Bisphenol A Based on Poly(Chromotropic Acid) Modified Glassy Carbon Electrode

Background: A new modified electrode based on the poly(chromotropic acid) (4,5-dihy-droxynaphthalene2,7-disulfonic acid) film was developed by electrochemical polymerization to explore its voltammetric behavior. The electrochemical synthesis of poly(chromotropic acid) was accomplished by applying an aqueous solution of sodium hydroxide as a supporting electrolyte (0.1 M). The electrochemical behaviors of bisphenol A (BPA) on poly(chromotropic acid) modified glassy carbon electrode (poly(CTA)/GCE) were researched by cyclic voltammetry, square wave voltammetry, and chronoam-perometry