Metabolic fingerprinting is a powerful analytical technique, giving access to high-throughput identification and relative quantification of multiple metabolites. Because of short analysis times, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is the preferred instrumental platform for fingerprinting, although its power in analysis of free fatty acids (FFAs) is limited. However, these metabolites are the biomarkers of human pathologies and indicators of food quality. Hence, a high-throughput method for their fingerprinting is required. Therefore, here we propose a MALDI-TOF-MS method for identification and relative quantification of FFAs in biological samples of different origins. Our approach relies on formation of monomolecular Langmuir films (LFs) at the interphase of aqueous barium acetate solution, supplemented with low amounts of 2,5-dihydroxybenzoic acid, and hexane extracts of biological samples. This resulted in detection limits of 10 −13 −10 −14 mol and overall method linear dynamic range of at least 4 orders of magnitude with accuracy and precision within 2 and 17%, respectively. The method precision was verified with eight sample series of different taxonomies, which indicates a universal applicability of our approach. Thereby, 31 and 22 FFA signals were annotated by exact mass and identified by tandem MS, respectively. Among 20 FFAs identified in Fucus algae, 14 could be confirmed by gas chromatography-mass spectrometry.
This article presents new possibilities of using thin
films of
lanthanide stearates as sorbent materials. Modification of the Q-sense
device resonator with monolayers of lanthanide stearates by the Langmuir–Schaeffer
method made it possible to study the process of insulin protein adsorption
on the surface of new thin-film sorbents. The resulting films were
also characterized by compression isotherms, chemical analysis, scanning
electron microscopy, and mass spectrometry. The transition of stearic
acid to salt was recorded by IR spectroscopy. Using the LDI MS method,
the main component of thin films, lanthanide distearate, was established.
The presence of Eu
2+
in thin films was revealed. In the
case of europium stearate, the maximum value of insulin adsorption
was obtained, −1.67·10
−10
mole/cm
2
. The findings suggest the possibility of using thin films
of lanthanide stearates as a sorption material for the proteomics
determination of the quantitative protein content in complex fluid
systems by specific adsorption on modified surfaces and isolation
of such proteins from complex mixtures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.