Rapid Evaluation of Suitable Substrates with High Affinity to Artificial Caffeine Receptors by MS Based Techniques

2005 ◽  
Vol 60 (10) ◽  
pp. 1077-1082 ◽  
Author(s):  
Daniela Mirk ◽  
Heinrich Luftmann ◽  
Siegfried R. Waldvogel

A modification of our triphenylene ketal based receptor facilitates electrospray tandem mass spectrometry investigations. Binding affinities of eleven potential substrates, e.g. caffeine and other xanthine alkaloids, are probed in the gas phase with collision induced dissociation. The relative stabilities of the substrate-receptor complexes are rapidly determined and the findings are correlated with the corresponding results in solution.

2018 ◽  
Vol 24 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Magdalena Frańska ◽  
Anna Michalak

The gas-phase stabilities of Tl+-crown ether complexes and Rb+-crown ether complexes were studied using the electrospray ionization-collision-induced dissociation-tandem mass spectrometry. Tl+ and Rb+ have identical ionic radii, thus a comparison of the properties of the crown ether complexes with these two cations seems to be justified. The selected crown ethers were 12C4 (it has a cavity smaller than the cation radius), 18C6 (it has a cavity of size similar to the cation radius), 24C8 (it has a cavity greater than the cation radius) and their conjugates. It has been found that the crown ether complexes of stoichiometry 1:1 with Tl+ are more or equally stable in the gas phase than the crown ether complexes with Rb+. However, 2:1 complexes with Tl+ are less stable than the complexes with Rb+.


2017 ◽  
Vol 10 (1) ◽  
pp. 100-109
Author(s):  
Hongxia Li ◽  
Natasha Trzaskalski ◽  
R.J. Neil Emery

Objective:A simple and fast high performance liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) method has been developed for the analysis of brassinosteroids (BRs) in plants without derivatization.Materials:The BRs (including castasterone, 24-epicastasterone, brassinolide and 24-epibrassinolide) have been extracted with ice cold 80% aqueous methanol solution.Method:Five different purification strategies have been tested for the purification and enrichment of BRs.Conclusion:This analytical method was sensitive, reliable, rapid and applicable to trace analysis in complex plant samples.


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