Separation of urea adducts in the analysis of complex mineral fertilisers

2016 ◽  
Vol 70 (3) ◽  
Author(s):  
Marcin Sadłowski ◽  
Barbara U. Grzmil ◽  
Krzysztof Lubkowski ◽  
Kinga Łuczka
Keyword(s):  
Analytical Separation ◽  
Urea Adducts

AbstractAn investigation of the analytical separation of free urea from its additive compounds with H

scholarly journals Ion Mobility–Mass Spectrometry for Bioanalysis

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 33
Author(s):  
Xavier Garcia ◽  
Maria del Mar Sabaté ◽  
Jorge Aubets ◽  
Josep Maria Jansat ◽  
Sonia Sentellas
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Biological Samples ◽  
Ion Mobility Mass Spectrometry ◽  
Exogenous Compounds ◽  
Analytical Separation

This paper aims to cover the main strategies based on ion mobility spectrometry (IMS) for the analysis of biological samples. The determination of endogenous and exogenous compounds in such samples is important for the understanding of the health status of individuals. For this reason, the development of new approaches that can be complementary to the ones already established (mainly based on liquid chromatography coupled to mass spectrometry) is welcomed. In this regard, ion mobility spectrometry has appeared in the analytical scenario as a powerful technique for the separation and characterization of compounds based on their mobility. IMS has been used in several areas taking advantage of its orthogonality with other analytical separation techniques, such as liquid chromatography, gas chromatography, capillary electrophoresis, or supercritical fluid chromatography. Bioanalysis is not one of the areas where IMS has been more extensively applied. However, over the last years, the interest in using this approach for the analysis of biological samples has clearly increased. This paper introduces the reader to the principles controlling the separation in IMS and reviews recent applications using this technique in the field of bioanalysis.

Phase Transitions of Urea Adducts with n-Paraffins under High Pressure

1990 ◽  
Vol 180 (2) ◽  
pp. 405-416 ◽  
Author(s):  
K. Fukao ◽  
T. Horiuchi ◽  
S. Taki ◽  
K. Matsushige
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Urea Adducts

Pyridine 1:1 adducts of urea (Z′ = 1) and thiourea (Z′ = 8)

2018 ◽  
Vol 74 (4) ◽  
pp. 406-410 ◽  
Author(s):  
Mark Strey ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Layer Structure ◽  
Urea Adduct ◽  
Standard Type ◽  
Space Group ◽  
Hydrogen Bond System ◽  
Bond System ◽  
Bifurcated Hydrogen Bond ◽  
Urea Adducts

During our studies of urea and thiourea adducts, we noticed that no adducts with unsubstituted pyridine had been structurally investigated. The 1:1 adduct of pyridine and urea, C5H5N·CH4N2O, crystallizes in the P21/c space group with Z = 4. The structure is of a standard type for urea adducts, whereby the urea molecules form a ribbon, parallel to the a axis, consisting of linked R 2 2(8) rings, and the pyridine molecules are attached to the periphery of the ribbon by bifurcated (N—H...)2N hydrogen bonds. The 1:1 adduct of pyridine and thiourea, C5H5N·CH4N2S, crystallizes in the P21/n space group, with Z = 32 (Z′ = 8). The structure displays similar ribbons to those of the urea adduct. There are two independent ribbons parallel to the b axis at z ≃ 0 and 1 \over 2, and three at z ≃ 1 \over 4 and 3 \over 4; the latter are crosslinked to form a layer structure by additional long N—H...S interactions, which each formally replace one branch of a bifurcated hydrogen-bond system.

Ionic Liquids Applied to Extraction of Xenobiotics from Food, Environmental, and Biological Samples and for Analysis by Liquid Chromatography

2019 ◽  
Vol 102 (1) ◽  
pp. 3-22
Author(s):  
Tomasz Tuzimski ◽  
Anna Petruczynik
Keyword(s):  
Ionic Liquids ◽  
Biological Samples ◽  
Solid Phase ◽  
Stationary Phases ◽  
Extraction Methods ◽  
Mobile Phase Additives ◽  
Environmental And Biological Samples ◽  
High System ◽  
Number Of Publications ◽  
Analytical Separation

Abstract Ionic liquids (ILs) are a class of unique substances composed purely by cation and anions. Because of the unique properties of ILs (e.g., electric conductivity, low volatility, thermostability, and tenability), their use has attracted considerable interest, including an increasing number of publications on their use in analytical separation techniques. ILs applied as extraction solvents in liquid–liquid extraction methods and promote interactions between the analyte and solvent because of their unique chemical functional groups. In solid-phase extraction, ILs are usually used for the modification of stationary phases. ILs in LC are applied as mobile phase additives to obtain a better peak shape and high system efficiency for the analysis of ionic, especially basic, compounds. This review highlights some of the applications of ILs to extraction and analysis by LC of xenobiotics in food, environmental, and biological samples.

Supermacroporous polyHIPE and cryogel monolithic materials as stationary phases in separation science: a review

2015 ◽  
Vol 7 (17) ◽  
pp. 6967-6982 ◽  
Author(s):  
Sidratul Choudhury ◽  
Damian Connolly ◽  
Blánaid White
Keyword(s):  
Stationary Phases ◽  
Separation Science ◽  
Internal Phase ◽  
Analytical Separation

With their unique supermacroporous architecture, polyHIPEs (high internal phase emulsions) and cryogels have huge potential as analytical separation stationary phases.

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