Organic Spot Test Analysis
About: This article is published in Analytical Chemistry.The article was published on 1955-08-01. It has received 30 citations till now. The article focuses on the topics: Spot analysis.
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TL;DR: In this paper, practical considerations concerning the various techniques that may be applicable to the separation of individual steroids by thin-layer chromatography (TLC) have been discussed, including the adsorbent, the preparation of the layer, and the type of solvent system to be employed for development of the chromatoplates.
Abstract: Publisher Summary The simple apparatus and techniques required for the development of thin-layer chromatograms, the high-power of resolution of thin-layer chromatography (TLC), and the possibility of employing a large number of reactions of great specificity and high sensitivity for the visualization of the analyzed compounds are major reasons for the acceptance that TLC has found as a separation procedure. Although TLC is employed in quantification procedures, it is even more widely used for preliminary separations and for purposes of identification. For preliminary separations, TLC is often used in conjunction with other methods of fractionation, such as column-partition chromatography and gas–liquid chromatography. This chapter deals with practical considerations concerning the various techniques that may be applicable to the separation of individual steroids by TLC. Factors that are taken into consideration when TLC is chosen as the method of fractionating mixtures of steroids include the adsorbent, the preparation of the layer, and the type of solvent system to be employed for development of the chromatoplates, and the technique to be used.
73 citations
TL;DR: Protein diazotization followed by alkaline coupling with a naphthol has been successfully applied for the histochemical localization of the protein bound tyrosine in tissues, with greater color intensities and superior histologic definition.
Abstract: Protein diazotization followed by alkaline coupling with a naphthol has been successfully applied for the histochemical localization of the protein bound tyrosine in tissues. Prolonged nitrous acid treatment in the cold is required (18-24 hours at 3°C). The best coupling reagent so far tried is 1-amimio-8-naphthol-4-sulfonic acid (S acid) and coupling succeeds best in a 1 % potassium hydroxide in 70 % alcohol, allowing 1 to 4 hours at 3°C. Topochemical results parallel those of the Millon reactions, with greater color intensities and superior histologic definition.
70 citations
TL;DR: The wax printing technology continues to overcome the current limitations and to be one of the promising fabrication techniques for microfluidic paper-based analytical devices (μPADs) and is expected to take place especially in the healthcare industry.
Abstract: Paper-based microfluidics has attracted attention for the last ten years due to its advantages such as low sample volume requirement, ease of use, portability, high sensitivity, and no necessity to well-equipped laboratory equipment and well-trained manpower. These characteristics have made paper platforms a promising alternative for a variety of applications such as clinical diagnosis and quantitative analysis of chemical and biological substances. Among the wide range of fabrication methods for microfluidic paper-based analytical devices (μPADs), the wax printing method is suitable for high throughput production and requires only a commercial printer and a heating source to fabricate complex two or three-dimensional structures for multipurpose systems. μPADs can be used by anyone for in situ diagnosis and analysis; therefore, wax printed μPADs are promising especially in resource limited environments where people cannot get sensitive and fast diagnosis of their serious health problems and where food, water, and related products are not able to be screened for toxic elements. This review paper is focused on the applications of paper-based microfluidic devices fabricated by the wax printing technique and used for international health. Besides presenting the current limitations and advantages, the future directions of this technology including the commercial aspects are discussed. As a conclusion, the wax printing technology continues to overcome the current limitations and to be one of the promising fabrication techniques. In the near future, with the increase of the current interest of the industrial companies on the paper-based technology, the wax-printed paper-based platforms are expected to take place especially in the healthcare industry.
68 citations
68 citations
TL;DR: It was of interest to determine the pathway for the biosynthesis of the tetronic acid structure in molds, particularly in view of the known mechanisms for n-ascorbic acid synthesis in mammals and of the apparently different pathway in plants.
24 citations
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01 Jan 1950
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