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Ashutosh Srivastava Renuka Abbi Anita Gupta Susmeet Bindra Sunil K. Singh 《Mikrochimica acta》1989,99(1-2):81-89
New spectrophotometric and titrimetric methods for the determination of sulphonamides withN-chlorosuccinimide (NCS) were developed. The spectrophotometric measurements can be made at 324–395 nm at pH 7.4 at room temperature, the stoichiometry being 1: 2, (p-H2N-C6H4-SO2NHR): (NCS) forming a dibromination product in presence of acidified potassium bromide. Potentiometrically or visually using methyl red as indicator, sulphonamides are titrated in pharmaceutical preparations by NCS always in presence of acidified potassium bromide. Ascorbic acid is determined alone and also in combinations, by first titrating it using potassium iodide and starch or 2,6-dichlorophenolindophenol as indicator. Acylation or diazotization of the aromatic amino groups that prevents substitution at the two ortho positions, is used as additional prereaction to analyze various binary and ternary mixtures of certain sulphonamides. These methods are accurate, simple, rapid, reproducible, useful at higher concentrations, do not involve any preseparation, and can tolerate several compounds that cause interference in other methods.Paper presented at the Eastern Analytical Symposium, New York, USA, 1985, No. 168 相似文献
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Summary This report describes a modified method for the separation and analysis of polyunsaturated fatty acids such as 20:4, 20:5,
and 22:6, using HPLC. The results show that these fatty acids are well separated from the saturated acids. Since the unsaturated
fatty acids elute earlier than saturated acids, and this method does not require the fractionation of free fatty acids using
thin layer chromatography, a necessary step for the gas chromatographic analysis, the recoveries of polyunsaturated fatty
acids were significantly higher as compared to those from gas chromatography. Furthermore, HPLC and gas chromatographic methods
gave identical results for the acyl chain composition of phosphatidylserine. The advantages of using HPLC over gas chromatography
in determining the acyl chain composition of free fatty acids and phospholipids are also discussed. 相似文献
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Krishna C. Joshi Renuka Jain Anshu Dandia Saroj Garg Nidhal Ahmed 《Journal of heterocyclic chemistry》1989,26(6):1799-1802
A new spiroheterocyclic system spiro[9H-acridine-9,3′-[3H]indol]-2′(1′H)-one and related compounds have been prepared by the reaction of spiro[3H-indole-3,9′-[9H]xanthen]-2(1H)-ones with aromatic amine or ammonium acetate. The latter were prepared by heating fluorinated indole-2,3-diones with m-/p-cresols or α-naphthol in the presence of sulphuric acid at 230-240°. The synthesized compounds have been characterized on the basis of their elemental analyses, ir, nmr (1H, 13C, 19F) and mass spectral data. 相似文献
100.
Graphene Quantum Dots: Simple and Cost‐Effective Synthesis of Fluorescent Graphene Quantum Dots from Honey: Application as Stable Security Ink and White‐Light Emission (Part. Part. Syst. Charact. 2/2016)
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