Synthesis and characterization of miniaturized aptamer-based monolithic sorbent for selective extraction of β-amyloid peptides from cerebrospinal fluid.

The ratio between beta-amyloid (Aβ) peptides 40 and 42 is recognized as a biomarker for Alzheimer's disease, playing a significant role in early diagnosis and disease progression monitoring. Aβ peptides are present at trace levels in cerebrospinal fluid, therefore, developing a new selective extraction procedure is essential for isolating targeted biomarkers from the matrix interferents, ensuring accurate identification and quantification. In this study, a hybrid organic-silica monolith was synthesized in a 530 µm inner diameter-capillary and used for the covalent grafting of beta amyloid peptide aptamers.

A novel restricted access-anion exchange organic monolithic phase for determining homocysteine and homocysteic acid in cerebrospinal fluid samples obtained from Alzheimer's disease patients by in-tube SPME-LC-MS/MS.

Background: High circulating concentrations of homocysteine (Hcy), a sulfur-containing amino acid, and homocysteic acid (HCA), an Hcy oxidized derivative, are an independent risk factor for developing Alzheimer's disease (AD), a neurodegenerative disorder that causes progressive cognitive decline. Therefore, these two endogenous compounds might be potential AD biomarkers. Nevertheless, few studies have attempted to quantify Hcy and HCA in the cerebrospinal fluid (CSF), the best validated fluid for evaluating neurodegenerative disorders.

Novel materials as capillary coatings for in-tube solid-phase microextraction for bioanalysis.

In-tube solid-phase microextraction with a capillary column as extraction device can be directly coupled with high-performance liquid chromatography systems (HPLC). The in-tube solid-phase microextraction technique has been continuously developed since it was introduced in 1997. New couplings have also been evaluated on the basis of state-of-the-art HPLC instruments.

Recent development of chromatographic methods to determine parabens in breast milk samples: A review.

Parabens have been widely used as antimicrobial preservatives in food, drugs, and cosmetics for over 60 years. These endocrine disruptors can alter both the wildlife and the human hormone function. Determining these compounds in human milk is important because breast milk plays an important role in infant growth and in neurocognitive development.

A column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry method to determine anandamide and 2-arachidonoylglycerol in plasma samples.

This study reports a fast, sensitive, and selective column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine the endocannabinoids (eCBs), anandamide (AEA), and 2-arachidonoylglycerol (2-AG) in plasma samples. This bidimensional system used a restricted access media column (RP-8 ADS, 25 mm × 4 mm × 25 μM) in the first dimension and a core-shell Kinetex C18 (100 mm × 2, 1.7 mm × 1 μM) column in the second dimension, followed by detection in a mass spectrometer triple quadrupole (multiple reactions monitoring mode) operating in the positive mode.