Organic Chemistry By Dr. I. L. Finar. Vol. 2: Stereochemistry and the Chemistry of Natural Products. Pp. xi + 733. (London and New York: Longmans, Green and Co., Ltd., 1956.) 40s. net.

Advanced Organic Chemistry

Paper has been present in the world of analytical chemistry for centuries, but it seems that just a few years back it was rediscovered as a valuable substrate for sensors. We can easily list some of the countless advantages of this simple cellulosic substrate, including mechanical properties, three-dimensional fibrous structure, biocompatibility and biodegradability, easiness of production and modification, reasonable price, and availability all over the world. Those characteristics make paper a first-choice substrate for disposable sensors and integrated sensing platforms. Nowadays, numerous examples of paper-based sensors are being presented in the literature. This review describes some of the most prominent examples classifying them by type of detection: optical (colorimetric, fluorescence, surface-enhanced Raman spectroscopy, and transmittance methods) and electrochemical (voltammetric, potentiometric, and conductivity-based methods). We take a closer look at recent advances in immunoassays fabricated on paper, excluding simple lateral flow tests assembled on nitrocellulose. This review also summarizes the main advantages and disadvantages of the use of paper as a substrate for sensors, as well as its impact on their performance and application, presents a short history of paper in analytical chemistry, and discusses fabrication methods and available sources of paper.

Sensing approaches on paper-based devices: a review

In this work, an Android application for measurement of nitrite concentration and pH determination in combination with a low-cost paper-based microfluidic device is presented. The application uses seven sensing areas, containing the corresponding immobilized reagents, to produce selective color changes when a sample solution is placed in the sampling area. Under controlled conditions of light, using the flash of the smartphone as a light source, the image captured with the built-in camera is processed using a customized algorithm for multidetection of the colored sensing areas. The developed image-processing allows reducing the influence of the light source and the positioning of the microfluidic device in the picture. Then, the H (hue) and S (saturation) coordinates of the HSV color space are extracted and related to pH and nitrite concentration, respectively. A complete characterization of the sensing elements has been carried out as well as a full description of the image analysis for detection. The re...

Smartphone-based simultaneous pH and nitrite colorimetric determination for paper microfluidic devices.

Centro de Quı́mica-Fı́sica Molecular (CQFM) and Institute of Nanosciences and Nanotechnology (IN), Departamento de Engenharia Quı́mica e Biológica, Instituto Superior Técnico, 1049-001 Lisboa, Portugal, REQUIMTE, Departamento de Quı́mica, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal, and iMed.UL, Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal

More sustainable approaches for the synthesis of N-based heterocycles.

Copper(II) ions capturing from water using ligand modified a new type mesoporous adsorbent

A new methodology for construction of a sensor array, to acquire signal patterns, is discussed in this article. This sensor is constructed by immobilizing an ionophore on a piece of paper (or porous material such as thin layer chromatography (TLC) plate) followed by charge coupled device (CCD) camera-based detection. This allows us to use non-transparent porous materials as a support for immobilization of ionophore. Changes in RGB values of color spots on pH paper or TLC strips create a pattern. The obtained pattern was analyzed using Microsoft Excel Solver. Full-range pH monitoring and speciation of ferric and ferrous ions in solution are discussed. A commercial multi-color pH strip was used as a typical prototype for full-range pH monitoring, and 4-methyl-2,6-bis (hydroxymethyl)phenol (or its halo-derivatives) and 1,10-phenanthroline were used as ionophores for determination of Fe(III) and Fe(II), respectively. Results of analyzed patterns showed a good correlation between predicted and true values of pH ( r  = 0.9986), Fe(II) ( r  = 0.9989) and Fe(III) ( r  = 0.9978) with acceptable relative standard error.

Speciation of iron(II), iron(III) and full-range pH monitoring using paptode: A simple colorimetric method as an appropriate alternative for optodes

Efficient method for the direct preparation of amides from carboxylic acids using tosyl chloride under solvent-free conditions

http://www.cs.gordon.edu/~ijl/_lead_papers/Direct%20amidation%20-%20microwave.pdf

Mohammad Navid Soltani Rad

Papers

Speciation of iron(II), iron(III) and full-range pH monitoring using paptode: A simple colorimetric method as an appropriate alternative for optodes

Efficient method for the direct preparation of amides from carboxylic acids using tosyl chloride under solvent-free conditions

Direct preparation of primary amides from carboxylic acids and urea using imidazole under microwave irradiation

Copper-doped silica cuprous sulfate (CDSCS) as a highly efficient and new heterogeneous nano catalyst for [3+2] Huisgen cycloaddition

A simple one-pot procedure for the direct conversion of alcohols into azides using TsIm