LC–MS/MS analysis of lipidized analogs of prolactin-releasing peptide utilizing a monolithic column and simple sample preparation

Bioanalysis ◽  
2017 ◽  
Vol 9 (17) ◽  
pp. 1319-1328
Author(s):  
Jana Zemenová ◽  
David Sýkora ◽  
Anna Freislebenová ◽  
Lenka Maletínská
2019 ◽  
Vol 6 (1) ◽  
pp. 30-41
Author(s):  
Ranjith Arimboor ◽  
Karunkara Ramakrishna Menon ◽  
Natarajan Ramesh Babu ◽  
Haneesh Chandran

Background:Increased consumer demand for curry leaves free from pesticides demands fast and reliable analytical methods for the analysis of pesticide residues.Objective:The optimization of a QuEChERS based sample preparation technique with improved analytical accuracy by removing interfering matrix components for LC-MS/MS analysis of pesticide residues from curry leaves.Methods:A modified QuEChERS solid phase extraction method was developed and validated for the analysis of 26 pesticides in fresh and dried curry leaves. The effects of the sample preparation steps and column retention time on the matrix suppression of analyte ions were also evaluated.Results:Validation parameters were found within an acceptable range. The matrix effect evaluation studies showed that the QuEChERS sample preparation was able to minimize the ion suppression of analytes due to co-eluting matrix of components and that a d-SPE clean up step had major role in reducing matrix effect. The gradient mobile phase with longer retention time for analytes resulted in comparatively lesser matrix effects than the isocratic mobile phase of non-polar nature. Even after the clean up, a considerable number of compounds had more than 20% reduction in their MS response in the gradient mobile phase.Conclusion:This study emphasized the need of proper sample clean up before a LC-MS/MS analysis and the usage of matrix matched standards and mobile phase that ultimately results in an appropriate analyte separation in reasonable retention times.


2019 ◽  
Vol 85 (4) ◽  
pp. 110-113
Author(s):  
Olexandr Ponomarenko ◽  
Anatolyi Samchuk ◽  
Kateryna Vovk ◽  
Igor Shvaika ◽  
Ganna Grodzinskaya

The analytical technologies of sample preparation of rocks and mushrooms using the microwave field for the determination of germanium by the method of mass spectrometry with inductively coupled plasma (ICP-MS analysis) have been developed. Germanium is a rare element. Germanium is homology of silicon and carbon. To date, the definition of low content of germanium in geological objects is a rather complex analytical task, which requires its concentration - extraction, co-precipitation, ion exchange. At present, the harmonious combination of the method of natural objects decomposition in the microwave field and germanium determination using ICP-MS analysis is particularly promising. Sample preparation of silicate rocks for ICP-MS determination of germanium was carried out by decomposition in a mixture of hydrofluoric, phosphate and nitric acids (5: 5: 2) in a microwave oven program at 240°C for 30 min. Sample preparation of mushrooms for ICP-MS germanium determination was carried out according to the following scheme. Initially, the dried sample was sealed in the presence of CaO, after dissolving it in a mixture of HNO3+HF+H3PO4 (6:6:1). Ge solution was extracted by Nazarenko V.A. extraction method. The developed analytical schemes have made it possible to significantly reduce the duration and labor intensity of sample preparation. The obtained solutions were analyzed using an inductively coupled plasma mass spectrometer. The developed method for determining germanium by ICP-MS analysis has been successfully tested on standard rock samples. The obtained results are in accordance with the accepted attribute, the relative standard deviation Sr ranges from 0.7-0.9. The data on the content and distribution of germanium in the Boletales fungi are obtained. They indicate wild mushrooms contain high levels of germanium, especially Boletus and Mushroom biospores. These studies are necessary because the essential properties of germanium and its compounds attract special attention of scientists today. Complementary Ge compounds which have hypotensive, bactericidal, antiviral and antitumor effects have already been synthesized.


2021 ◽  
Author(s):  
Hankum Park ◽  
Frances V Hundley ◽  
J. Wade Harper

We present a protocol for sample preparation for LC-MS analysis of whole cell lysates and for lysosomal and endosomal fractions purified by Lyso-IP and Endo-IP. Protocols for purification of lysosomes and endosomes is provided in protocol dx.doi.org/10.17504/protocols.io.byi9puh6 using cells that express endogenously tagged TMEM192-HA and stably expressing FLAG-EEA1 as descrbed in dx.doi.org/10.17504/protocols.io.byi7puhn.


Author(s):  
L. Calamai ◽  
F. Villanelli ◽  
G. Bartolucci ◽  
G. Pieraccini ◽  
G. Moneti

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