Liquid chromatographic strategies for separation of bioactive compounds in food matrices

Nowadays, there is an increasing attention for nutraceuticals and, in general, bioactive compounds naturally present in food. Indeed, the possibility of preserving human health and preventing disease (e.g., cardiovascular diseases, cancer etc.) by the intake of healthy food is attractive for both consumers and food industries. In turn, research in this field was also prompted significantly, with the aim of characterizing these bioactive compounds and ascribe to them a specific activity. The bioactive compounds can belong to several chemical classes. However, their chemical diversity and presence in complex matrices, such as food, make it challenging both their isolation and characterization. To tackle this issue, efficient separation systems are needed, which are mainly based on chromatography. In this context, this mini-review aims to provide the reader with an overview of the most relevant and recent approaches for the separation of the most common bioactive compounds in food, in particular polyphenols, phenols, carotenoids, and peptides, by liquid chromatography approaches. © 2018 by the authors

Development of a rapid LC-MS/MS Method for the determination of emerging fusarium mycotoxins enniatins and beauvericin in human biological fluids

A novel method for the simultaneous determination of enniatins A, A1, B and B1 and beauvericin, both in human urine and plasma samples, was developed and validated. The method consisted of a simple and easy pretreatment, specific for each matrix, followed by solid phase extraction (SPE) and detection by high performance liquid chromatography-tandem mass spectrometry with an electrospray ion source. The optimized SPE method was performed on graphitized carbon black cartridges after suitable dilution of the extracts, which allowed high mycotoxin absolute recoveries (76%-103%) and the removal of the major interferences from the matrix. The method was extensively evaluated for plasma and urine samples separately, providing satisfactory results in terms of linearity (R² of 0.991-0.999), process efficiency (>81%), trueness (recoveries between 85% and 120%), intra-day precision (relative standard deviation, RSD < 18%), inter-day precision (RSD < 21%) and method quantification limits (ranging between 20 ng·L(-)¹ and 40 ng·L(-)¹ in plasma and between 5 ng·L(-)¹ and 20 ng·L(-)¹ in urine). Finally, the highly sensitive validated method was applied to some urine and plasma samples from different donors

New Magnetic Graphitized Carbon Black TiO2 Composite for Phosphopeptide Selective Enrichment in Shotgun Phosphoproteomics

Graphitized carbon black (GCB) has been employed for extraction of several classes of analytes, due to the large surface area and the unique chemistry of its surface groups that allows for extracting a wide range of analytes, including polar, acidic compounds. Despite the fact that structurally related materials, such as graphene, found application as hybrid-components in phosphoproteomics, surprisingly, GCB has never been used for the selective enrichment of phosphopeptides. For this purpose, in the present work we used GCB to prepare a magnetic composite with TiO2 (mGCB@TiO2) that was then applied to yeast total extracts. We exploited the high surface area provided by nanostructures, the presence of nano-TiO2 for selective binding of phosphopeptides, and the magnetic responsiveness of magnetite for solid-phase separation. The material was extensively characterized at each modification step by transmission electron microscopy, Fourier-transformed infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, and porosimetry. Next, the new system was applied for the enrichment of casein phosphopeptides from a simulated tryptic digest with bovine serum albumin (BSA:casein, 100:1). Finally, after assessing the potential applicability, the composite was employed for enriching phosphopeptides from yeast protein digests. This allowed us not only to optimize the enrichment protocol but also to fully compare its performance to commercial TiO2 spin columns. To achieve this aim, the optimized enrichment protocol was included in a typical shotgun proteomics analytical workflow based on nanoHPLC-MS/MS analysis

Comprehensive identification of native medium-sized and short bioactive peptides in sea bass muscle

Native peptides from sea bass muscle were analyzed by two different approaches: medium-sized peptides by peptidomics analysis, whereas short peptides by suspect screening analysis employing an inclusion list of exact m/z values of all possible amino acid combinations (from 2 up to 4). The method was also extended to common post-translational modifications potentially interesting in food analysis, as well as non-proteolytic aminoacyl derivatives, which are well-known taste-active building blocks in pseudo-peptides. The medium-sized peptides were identified by de novo and combination of de novo and spectra matching to a protein sequence database, with up to 4077 peptides (2725 modified) identified by database search and 2665 peptides (223 modified) identified by de novo only; 102 short peptide sequences were identified (with 12 modified ones), and most of them had multiple reported bioactivities. The method can be extended to any peptide mixture, either endogenous or by protein hydrolysis, from other food matrices. © 2020 Elsevier Lt

Polydopamine-coated magnetic nanoparticles for isolation and enrichment of estrogenic compounds from surface water samples followed by liquid chromatography-tandem mass spectrometry determination

Estrogens, phytoestrogens, and mycoestrogens may enter into the surface waters from different sources, such as effluents of municipal wastewater treatment plants, industrial plants, and animal farms and runoff from agricultural areas. In this work, a multiresidue analytical method for the determination of 17 natural estrogenic compounds, including four steroid estrogens, six mycoestrogens, and seven phytoestrogens, in river water samples has been developed. (Fe3O4)-based magnetic nanoparticles coated by polydopamine (Fe3O4@pDA) were used for dispersive solid-phase extraction, and the final extract was analyzed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The Fe3O4 magnetic nanoparticles were prepared by a co-precipitation procedure, coated by pDA, and characterized by scanning electron microscopy, infrared spectroscopy, and elemental analysis. The sample preparation method was optimized in terms of extraction recovery, matrix effect, selectivity, trueness, precision, method limits of detection, and method limits of quantification (MLOQs). For all the 17 analytes, recoveries were >70 % and matrix effects were below 30 % when 25 mL of river water sample was treated with 90 mg of Fe3O4@pDA nanoparticles. Selectivity was tested by spiking river water samples with 50 other compounds (mycotoxins, antibacterials, conjugated hormones, UV filters, alkylphenols, etc.), and only aflatoxins and some benzophenones showed recoveries >60 %. This method proved to be simple and robust and allowed the determination of natural estrogenic compounds belonging to different classes in surface waters with MLOQs ranging between 0.003 and 0.1 μg L(-1). Graphical Abstract Determination of natural estrogenic compounds in water by magnetic solid phase extraction followed by liquid chromatography-tandem mass spectrometry analysis

Magnetic materials for the selective analysis of peptide and protein biomarkers

This mini-review article provides an overview on the use of magnetic materials for the analysis of protein biomarkers. In particular, the advantage provided by magnetic solid phase extraction will be discussed with selected examples, considering untargeted analysis for screening new biomarker proteins and targeted investigation on known and suggested new biomarkers. Aspects, such as enrichment efficiency over conventional techniques, ease of use, functionalization versatility and automation will be considered, together with quantification and deeper structure elucidation provided by coupling selective or specific enrichment to powerful characterization techniques, such as mass spectrometr

Determination of Enantioselectivity and Enantiomeric Excess by Mass Spectrometry in the Absence of Chiral Chromatographic Separation: An Overview

This review describes the principles and instrumentation for the screening of asymmetric reactions by mass spectrometry. These techniques witnessed a significant advancement in the last few years. Although some of them are still at the proof-of-concept development stage, several applications might be foreseen in the field of combinatorial, high-throughput parallel catalyst screening