The development of quantitative and qualitative analytical methods to assess microplastics (MPLs) and nano-plastics (NPLs) content in the environment is a central issue for realistic risk assessment studies. However, the quantitative analysis continues being a critical issue, in particular for MPLs from 100 µm down to the nano-sized range in complex environmental samples. This paper evaluates the potential of mass spectrometry for the analysis of MPLs and NPLs. The performance of different techniques including matrix-assisted laser desorption ionisation (MALDI) coupled to time-of-flight mass spectrometry (TOF-MS), liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS), and the ambient ionization approaches as desorption electrospray ionisation (DESI) and direct analysis real-time (DART), were assessed for the study of polystyrene (PS) MPLs and NPLs in natural waters.A method based on LC-HRMS, equipped with an atmospheric pressure photoionization source (APPI), operated in negative conditions for the quantitative analysis of PS MPLs and NPLs in natural waters, was developed. The chromatographic separation was achieved using an advanced polymer chromatographic (APC) column using toluene isocratic as the mobile phase. The optimal analytical method showed an instrumental limit of detection (ILOD) of 20 pg and methods limits of detection and quantification around 30 pg L -1 and 100 pg L -1 , respectively. And, recoveries of 60 and 70% in samples from rivers and the marine coast, respectively. The performance of the new method was proved by the analysis of fortified samples and natural seawater samples.

Abstract:High performance liquid chromatography-ultraviolet (HPLC-UV) was applied to the analysis and characterization of olive oils and other vegetable oils. A chromatographic separation on a Zorbax Eclipse XDB-C8 reversed-phase column was proposed under gradient elution, employing 0.1% formic acid aqueous solution and methanol as mobile phase, for the determination of 14 polyphenols and phenolic acids, allowing us to obtain compositional profiles in less than 20 min. Acceptable sensitivity (limit of detection (LOD) values down to 80 µg/L in the best of cases), linearity (r 2 higher than 0.986), good run-to-run and day-to-day precisions (relative standard deviation (RSD) values lower than 11.5%), and method trueness (relative errors lower than 6.8%) were obtained. The proposed HPLC-UV method was then applied to the analysis of 72 oil samples (47 olive oils and 27 vegetable oils including sunflower, soy, corn, and mixtures of them). Analytes were recovered using a liquid-liquid extraction method employing ethanol:water 70:30 (v/v) solution and hexane as extracting and defatting solvents, respectively. HPLC-UV polyphenolic profiles using peak areas were then analysed by principal component analysis (PCA) to extract information from the most significant data contributing to the characterization and classification of olive oils against other vegetable oils, as well as among Arbequina and Picual olive oil varieties. PCA results showed a noticeable difference between olive oils and the other classes. In addition, a reasonable discrimination of olive oils as a function of fruit varieties was also encountered.

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BACKGROUND Rosemary forms an arbuscular mycorrhizal (AM) symbiosis with a group of soilborne fungi belonging to the phylum Glomeromycota, which can modify the plant metabolome responsible for the antioxidant capacity and other health beneficial properties of rosemary. RESULTS The effect of inoculating rosemary plants with an AM fungus on their growth via their polyphenolic fingerprinting was evaluated after analyzing leaf extracts from non‐inoculated and inoculated rosemary plants by ultra‐high performance liquid chromatography‐high resolution mass spectrometry (UHPLC‐HRMS). Plant growth parameters indicated that mycorrhizal inoculation significantly increased plant height and biomass. Chemical modifications in the plant polyphenolic profile distribution were found after a principal components analysis (PCA) loading plots study. Four compounds hosting strong antioxidant properties – ferulic acid, asiatic acid, carnosol, and vanillin – were related to mycorrhizal rosemary plants while caffeic and chlorogenic acids had a higher influence on non‐mycorrhizal plants. CONCLUSION Mycorrhization was found to stimulate growth to obtain a higher biomass of plant leaves in a short time, avoiding chemical fertilization, while analytical results demonstrate that there is an alteration in the distribution of polyphenols in plants colonized by the symbiotic fungus, which can be related to an improvement in nutritional properties with future industrial significance. © 2018 Society of Chemical Industry