Coceth sulfate characterization by electrospray ionization tandem mass spectrometry

Analysis of surfactants by mass spectrometry: Coming to grips with their diversity

Surfactants are surface-active agents widely used in numerous applications in our daily lives as personal care products, domestic, and industrial detergents. To determine complex mixtures of surfactants and their degradation products, unselective and rather insensitive methods, based on colorimetric and complexometric analyses are no longer employable. Analytical methodologies able to determine low concentration levels of surfactants and closely related compounds in complex matrices are required. The recent introduction of robust, sensitive, and selective mass spectrometry (MS) techniques has led to the rapid expansion of the surfactant research field including complex mixtures of isomers, oligomers, and homologues of surfactants as well as their chemically and biodegradation products at trace levels. In this review, emphasis is given to the state-of-the-art MS-based analysis of surfactants and their degradation products with an overview of the current research landscape from traditional methods involving hyphenate techniques (gas chromatography-MS and liquid chromatography-MS) to the most innovative approaches, based on high-resolution MS. Finally, we outline a detailed explanation on the utilization of MS for mechanistic purposes, such as the study of micelle formation in different solvents.

Analytical Methods for Extraction and Identification of Primary and Secondary Metabolites of Apple (Malus domestica) Fruits: A Review

Apples represent a greater proportion of the worldwide fruit supply, due to their availability on the market and to the high number of existing cultivar varieties and apple-based products (fresh fruit, fruit juice, cider and crushed apples). Several studies on apple fruit metabolites are available, with most of them focusing on their healthy properties’ evaluation. In general, the metabolic profile of apple fruits strongly correlates with most of their peculiar characteristics, such as taste, flavor and color. At the same time, many bioactive molecules could be identified as markers of a specific apple variety. Therefore, a complete description of the analytical protocols commonly used for apple metabolites’ characterization and quantification could be useful for researchers involved in the identification of new phytochemical compounds from different apple varieties. This review describes the analytical methods published in the last ten years, in order to analyze the most important primary and secondary metabolites of Malus domestica fruits. In detail, this review gives an account of the spectrophotometric, chromatographic and mass spectrometric methods. A discussion on the quantitative and qualitative analytical shortcomings for the identification of sugars, fatty acids, polyphenols, organic acids, carotenoids and terpenes found in apple fruits is reported.

Characterization of Quercetin Derivatives in Crossing Combination of Habanero White and Capsicum annuum Peppers and of Anti-Inflammatory and Cytotoxic Activity

The overproduction of reactive oxygen species and the exposure of the human body to free radicals contribute to the aetiology of many chronic health problems, such as cardiovascular disease and cancer. Supplementation with natural antioxidants could be helpful, preventing free-radical-induced tissue damage through the inhibition of the radicals’ formation. Quercetin derivatives have recently been shown to inhibit the production of inflammatory mediators and to reduce the proliferation of tumoral cells, thus being valid compounds to be promoted as dietary supplements. In this work, an HPLC-MS/MS investigation on the derivatives of quercetin in a methanolic extract of peppers deriving from an original crossing combination between Habanero white and Capsicum annuum revealed the occurrence of nine glycoconjugates, either monosaccharide, disaccharide or trisaccharide, as well as an acylated disaccharidic derivative (i.e., quercetin rhamnoside-(feruloyl-hexoside)). Due to the great variability in the quercetin derivatives’ profiles, the Habanero white hybrid pepper extract was subjected to in vitro cytotoxicity assays. The pepper extract under study was proved to have anti-inflammatory activity comparable to that shown by a Capsicum annuum pepper extract since it reduced ROS levels compared to activated cells. Due to its beneficial effects, it could be exploited as a natural constituent of nutraceutical formulations.

Untargeted analysis of pure snail slime and snail slime-induced Au nanoparticles metabolome with MALDI FT-ICR MS

Chronic wounds result from the failure of the normal wound healing process. Any delay during the tissue repair process could be defined as chronic wound healing, potentially having a highly detrimental impact on human health. To face this problem, in the last years, the use of different technologies alternative to therapeutic agents is gaining more attention. The Helix aspersa snail slime-based products are increasingly being used for skin injury, thanks to their ability to make tissue repair processes faster. To date, a comprehensive overview of pure snail slime metabolome is not available. Besides, Au nanoparticles (AuNPs) technology is spreading rapidly in the medical environment, and the search for AuNPs "green" synthetic routes that involve natural products as precursor agents is demanded, alongside with a deep comprehension of the kind of species that actively take part in synthesis and product stabilization. The aim of this work is to characterize the metabolic profile of a pure snail slime sample, by an untargeted high-resolution mass spectrometry-based analysis. In addition, insights on AuNPs synthesis and stabilization by the main components of pure snail slime used to induce the synthesis were obtained. The untargeted analysis provided a large list of important classes of metabolites, that is, fatty acid derivatives, amino acids and peptides, carbohydrates and polyphenolic compounds that could be appreciated in both samples of slime, with and without AuNPs. Moreover, a direct comparison of the obtained results suggests that mostly nitrogen and sulfur-bearing metabolites take part in the synthesis and stabilization of AuNPs.

A novel charge derivatization-direct infusion mass spectrometry method for the quantitative analysis of C1-C8 fatty acids in rubber seed oil-based biodiesel

The free fatty acids that contain one to eight carbons (C₁-C₈) in biodiesel would affect the quality of biodiesel. It is still a matter of challenge to simultaneously determine the composition of C₁-C₈ fatty acids in seed oil and seed oil-based biodiesel. Herein, a novel method of charge derivatization coupling with direct infusion mass spectrometry (CD-DIMS) was developed for the determination of the C₁-C₈ fatty acids in biodiesels. A fixed-charge derivatization reagent, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide (CMCT), was used to convert fatty acids into their cationic derivatives, which significantly improved the sensitivity and selectivity of detection. Good linearity was observed with the limits of detection (LODs) in the range of 0.0002-0.001 μg mL^-1 for the investigated fatty acids. The recovery was in the range of 85.1%-101.9% and the matrix effect was within the range of 75.5-93.2%. The developed method was carried out to analyze C₁-C₈ fatty acids in rubber seed oil (RSO) and RSO-based biodiesels produced by different catalysts, including NaOH, TiO₂, and carbodiimide. It was also applied to the dynamic monitoring of C₁-C₈ fatty acids in RSO and produced RSO biodiesels during the oxidation process. As results, formic acid, acetic acid, and propionic acid were detected in aged RSO and biodiesel samples. The contents of formic acid, acetic acid, and propionic acid all increased in aged RSO and biodiesels, but with different growth rates. These results demonstrated that the developed CD-DIMS method can provide a quick, accurate, and sensitive analysis of C₁-C₈ fatty acids in seed oil and biodiesel samples.

Natural Polymeric Materials: A Solution to Plastic Pollution from the Agro-Food Sector

Conventional petroleum-derived plastics represent a serious problem for global pollution because, when discarded in the environment, are believed to remain for hundreds of years. In order to reduce dependence on fossil resources, bioplastic materials are being proposed as safer alternatives. Bioplastics are bio-based and/or biodegradable materials, typically derived from renewable sources. Food waste as feedstock represents one of the recent applications in the research field of bioplastics production. To date, several food wastes have been used as raw materials for the production of bioplastics, including mostly fruit and vegetable wastes. The conversion of fruit and vegetable wastes into biomaterials could occur through simple or more complex processes. In some cases, biopolymers extracted from raw biomass are directly manufactured; on the other hand, the extracted biopolymers could be reinforced or used as reinforcing agents and/or natural fillers in order to obtain biocomposites. The present review covers available results on the application of methods used in the last 10 years for the design of biomaterials obtained from formulations made up with both fruits and vegetables by-products. Particular attention will be addressed to the waste pre-treatment, to the bioplastic formulation and to its processing, as well as to the mechanical and physical properties of the obtained materials.