Advanced search
Start date
Betweenand

Development of an organic monolithic phase for the determination of b-amyloid peptides AB40 and AB42 in plasma samples from patients with Alzheimer's Disease by UHPLC-MS/MS in column switching mode

Grant number: 19/04386-7
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): July 01, 2019
Effective date (End): June 30, 2022
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Maria Eugênia Queiroz Nassur
Grantee:Caroline Fernandes Grecco
Home Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Associated research grant:17/02147-0 - Single drop chromatography and its coupling to mass spectrometry: instrumental strategies, development of materials, automation and analytical applications, AP.TEM

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative dementia that affects about 5% of the world's population over 65 years old. It can also occur in individuals under 40 years of age (AD). AD is pathologically characterized by the presence of neuritic plaques and neurofibrillary tangles. The formation of neuritic plaques is due to the extracellular accumulation of the ²-amyloid peptides, whereas the neurofibrillary cells originate through the accumulation of the tau protein. Most drugs developed for the treatment of AD seek to reduce production, prevent aggregation and / or promote the elimination of ²-amyloid peptides. Considering the negative impacts of AD on the life of patients, causing them to lose autonomy in routine activities and making them dependent on the help of third parties, it is essential to have a disease-modifying or preventive treatment. In this sense, the studies have been directed to the determination of ²-amyloid peptides as possible biomarkers of Alzheimer's disease in biological fluids. Liquid chromatography coupled to tandem mass spectrometry (LC-MS / MS) has been used in the determination of endogenous compounds in biological fluids. The sample preparation step has been required in the development of LC-MS / MS methods, to eliminate the interferents and to preconcentrate the analytes, almost always present at trace levels in the biological samples. LC-MS / MS in column switching mode allows automation of the analyzes by hyphenation of the preparation step of biological samples (pre-concentration of the analytes and removal of a large part of the interfering components) with the chromatographic system. Organic monolithic biocompatible materials can be prepared by in situ polymerization, directly inside the fused silica capillary and have some advantages such as high stability in wide pH range, easy and fast preparation, low pressure in the analytical system and high permeability. In this project, the LC-MS / MS method in column switching mode will be developed and validated for the determination of ²-amyloid A²40 and A²42 peptides in plasma samples from patients with Alzheimer's disease. An organic monolith with sulphonic groups will be synthesized inside fused silica capillaries and used in the first dimension (1D) of the column switching system. The coating of the monolithic material with restricted access materials (RAM) will also be evaluated. In the second dimension (2D) of the column switching system two analytical columns will be evaluated, one in reversed phase (RP) and the other using hydrophilic interaction liquid chromatography (HILIC).