Development of a flotation-spectrophotometric method for determination of cetylpyridinium chloride in pharmaceutical products

A new simple and sensitive flotation-spectrophotometric method for the determination of cetylpyridinium chloride (CPC) is reported. The method is based on the formation of an ion- associate between CPC and Orange II (OR) which is floated in the interface of aqueous phase and n-hexane by vigorous shaking. The aqueous solution was discarded and the adsorbed ion associate on to the wall of a separating funnel was dissolved in a small volume of methanol solvent and its absorbance was measured at 480 nm. The apparent molar absorptivity (Ε) of the ion associate was determined to be 4.12 x 10(5) L mol-1 cm-1. The calibration graph was linear in the concentration range of 15-800 ng mL-1 of CPC with a correlation coefficient of 0.9988. The limit of detection (LOD) was 10.8 ng mL-1. The relative standard deviation (RSD) for determination of 100 and 800 ng mL-1 of CPC was 3.47 and 2.04% (n=7), respectively. The method was successfully applied to the determination of CPC in a commercial mouth washer product

Simultaneous preconcentration of Cu(II), Cd(II) and Mn(II) on silica-polyethylene glycol and determination by flame atomic absorption spectrometry

A simultaneous solid phase extraction procedure for enrichment of Cu(II), Cd(II) and Mn(II) has been developed. The method is based on adsorption of Cu(II), Cd(II) and Mn(II) ions on polyethylene glycol-silica gel pre-conditioned with acetate buffer (pH 5.5). The adsorbed metal ions are eluted with nitric acid (1 mol L -1) and determined by flame atomic absorption spectrometry. The calibration graph was linear in the range of 2-140 ng mL-1 for Cu(II), 1-40 ng mL-1 for Cd(II) and 4-100 ng mL-1 for Mn(II). The limits of detection were 0.66, 0.33 and 1.20 ng mL-1 for Cu(II), Cd(II) and Mn(II), respectively

Spectrophotometric Determination of Iron(II) after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

A new solid phase extraction procedure was developed for preconcentration of iron(II) using silica gel-polyethylene glycol (silica-PEG) as an adsorbent. e method is based on retention of iron(II) as 2,2 � bipyridine complex on silica-PEG. e retained complex is eluted by 1.0 mol L −1 of sulfuric acid-acetone mixture (1:2) and its absorbance is measured at 518 nm, spectrophotometrically. e effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. e calibration graph was linear in the range of 1-60 ng mL −1 of iron(II). e limit of detection based on 3S b was 0.57 ng mL −1 and relative standard deviations (R.S.D) for ten replicate measurements of 12 and 42 ng mL −1 of iron(II) were 2.4 and 1.7%, respectively. e method was applied to the determination of of iron(II) in water, multivitamin tablet, and spinach samples

Nanopaper as an Optical Sensing Platform

Bacterial cellulose nanopaper (BC) is a multifunctional material known for numerous desirable properties: sustainability, biocompatibility, biodegradability, optical transparency, thermal properties, flexibility, high mechanical strength, hydrophilicity, high porosity, broad chemical-modification capabilities and high surface area. Herein, we report various nanopaper-based optical sensing platforms and describe how they can be tuned, using nanomaterials, to exhibit plasmonic or photoluminescent properties that can be exploited for sensing applications. We also describe several nanopaper configurations, including cuvettes, plates and spots that we printed or punched on BC. The platforms include a colorimetric-based sensor based on nanopaper containing embedded silver and gold nanoparticles; a photoluminescent-based sensor, comprising CdSe@ZnS quantum dots conjugated to nanopaper; and a potential up-conversion sensing platform constructed from nanopaper functionalized with NaYF₄:Yb³⁺@Er³⁺&SiO₂ nanoparticles. We have explored modulation of the plasmonic or photoluminescent properties of these platforms using various model biologically relevant analytes. Moreover, we prove that BC is and advantageous preconcentration platform that facilitates the analysis of small volumes of optically active materials (∼4 μL). We are confident that these platforms will pave the way to optical (bio)sensors or theranostic devices that are simple, transparent, flexible, disposable, lightweight, miniaturized and perhaps wearable

Biofabricated Nanostructures and Their Composites in Regenerative Medicine

Biosynthesis of nanomaterials is gaining attention as a sustainable, environmentally friendly, and reliable method for manufacturing a extensive array of nanostructures, such as metal/metal oxides and organic and hybrid materials. Green synthesis is considered a crucial tool to reduce the harsh effects associated with conventional synthesis. Nanocomposite materials containing biosynthesized nanostructures are highly sought after in regenerative medicine. In the present Review, biosynthesis of metal/metal oxides and carbon-based nanomaterials using microorganisms (e.g., bacteria and fungi) and natural compounds (e.g., polysaccharides, proteins, fruit juices, and plant extracts) is highlighted. The toxicity of biosynthesized nanoparticles for biomedical application is also reviewed in depth. The applications of bionanocomposites prepared from these ecofriendly nanoparticles in tissue engineering are reviewed to provide readers with a background for future studies.<br/