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The exposure of humans to microplastics through food is a topic of great interest. Foods of marine origin, such as fish and salt, have been the most extensively studied in this regard. Conversely, foods considered less likely to be contaminated (such as dairy products) have been investigated to a lesser extent. This is the first study addressing the occurrence of microplastics in cheese. In this paper, we report the first analytical approach for cheese preparation, before a chemical analysis of microplastics in cheese was performed. Therefore, the most suitable digestion methods were investigated. Alkaline digestion (i.e., KOH 5 M, 50 °C, 48 h) achieved a digestion efficiency of 97.5 ± 0.8%. To assess the feasibility of the preparative method proposed, a recovery rate of spiked polystyrene microbeads (~10 µm) of 98.5 ± 0.4% was determined. Further, the effects of the digestion agent on the microbeads were also investigated. To confirm whether the preparative method allows for the confirmation of the plastic-nature of microparticles, a qualification of spiked microplastics (polystyrene, 150 µm, and polyethylene terephthalate, 300 µm) was performed using pyrolysis–gas chromatography–mass spectrometry.

The main problem of implementation of technology of rutin extraction from grass buckwheat Fagopyrum sagittatum Gilib. lies in purification of rutin raw. In this connection the following research object is determined: consideration of the possibility to use for rutin raw purification different commercial carbon brands as adsorbents by the method of preparative chromatography and assessment of their effectiveness to achieve the maximum degree of purification with minimum duration of the elution process. The article presents experimental data on purification of rutin raw sample, extracted from grass buckweat green material by the preparative chromatography method using wood- and coconut-based activated carbons of different brands as sorbents; besides, the following items are presented in the article: dependence of rutin sample melting temperature, qualitative and quantitative flavonoid content, authenticity on chlorophyll and red pigments content depending on sorbent layer height and elution duration in comparison with the GSO [State Standard Samples] control sample. To confirm the reliability of the obtained results, statistical processing of experimental data is conducted using the methods of correlation and regression analysis, as well as using the two-parameter normal distribution of values. It is demonstrated that the use of the following carbon brands, indicated in decreasing effectiveness order, can provide the best purity and stability of parameters values, characterizing the product: NWС-P, NWM-P, OU-A, OU-B; the conducted calculations indicate that the best correlation between the sorbent layer height in a column and the rutin samples quality parameter was achieved when the carbons of the brands NWM-P, ОY-А and ОY-В were used. Depending on the tasks, rutin purification degree may be regulated by sequential use of NWC-P and NWM-P carbons. When rutin is purified from proximate admixtures, chlorophyll and red pigments, NWC-P adsorbent allows to get a comparable result even when the layer height is from 50 to 70 mm respectively.

This chapter contains sections titled: Photophysical processes Energy transfer, quenching and sensitization A classification of photochemical reaction pathways Problems

This chapter contains sections titled: References Problems

RNA is becoming more important as an increasing number of functions, both regulatory and enzymatic, are being discovered on a daily basis. As the RNA boom has just begun, most techniques are still in development and changes occur frequently. To understand RNA functions, revealing the structure of RNA is of utmost importance, which requires sample preparation. We review the latest methods to produce and purify a variation of RNA molecules for different purposes with the main focus on structural biology and biophysics. We present a guide aimed at identifying the most suitable method for your RNA and your biological question and highlighting the advantages of different methods.

Enantiomeric separation is a key step in the development of a new chiral drug. Preparative liquid chromatography (LC) continues to be the technique of choice either during the drug discovery process, to achieve a few milligrams, or to a scale-up during the clinical trial, needing kilograms of material. However, in the last few years, instrumental and technical developments allowed an exponential increase of preparative enantioseparation using other techniques. Besides LC, supercritical fluid chromatography (SFC) and counter-current chromatography (CCC) have aroused interest for preparative chiral separation. This overview will highlight the importance to scale-up chiral separations in Medicinal Chemistry, especially in the early stages of the pipeline of drugs discovery and development. Few examples within different methodologies will be selected, emphasizing the trends in chiral preparative separation. The advantages and drawbacks will be critically discussed.

The analysis of pomegranate phenolic compounds belonging to different classes in different fruit parts was performed by high-performance liquid chromatography coupled with photodiode array and mass spectrometry detection. Two different separation methods were optimized for the analysis of anthocyanins and hydrolyzable tannins along with phenolic acids and flavonoids. Two C18 columns, core–shell and fully porous particle stationary phases, were used. The parameters for separation of phenolic compounds were optimized considering chromatographic resolution and analysis time. Thirty-five phenolic compounds were found, and 28 of them were tentatively identified as belonging to four different phenolic compound classes; namely, anthocyanins, phenolic acids, hydrolyzable tannins, and flavonoids. Quantitative analysis was performed with a mixture of nine phenolic compounds belonging to phenolic compound classes representative of pomegranate. The method was then fully validated in terms of retention time precision, expressed as the relative standard deviation, limit of detection, limit of quantification, and linearity range. Phenolic compounds were analyzed directly in pomegranate juice, and after solvent extraction with a mixture of water and methanol with a small percentage of acid in peel and pulp samples. The accuracy of the extraction method was also assessed, and satisfactory values were obtained. Finally, the method was used to study identified analytes in pomegranate juice, peel, and pulp of six different Italian varieties and one international variety. Differences in phenolic compound profiles among the different pomegranate parts were observed. Pomegranate peel samples showed a high concentration of phenolic compounds, ellagitannins being the most abundant ones, with respect to pulp and juice samples for each variety. With the same samples, total phenols and antioxidant activity were evaluated through colorimetric assays, and the results were correlated among them.

Imaging single proteins has been a long-standing ambition for advancing various fields in natural science, as for instance structural biology, biophysics, and molecular nanotechnology. In particular, revealing the distinct conformations of an individual protein is of utmost importance. Here, we show the imaging of individual proteins and protein complexes by low-energy electron holography. Samples of individual proteins and protein complexes on ultraclean freestanding graphene were prepared by soft-landing electrospray ion beam deposition, which allows chemical- and conformational-specific selection and gentle deposition. Low-energy electrons do not induce radiation damage, which enables acquiring subnanometer resolution images of individual proteins (cytochrome C and BSA) as well as of protein complexes (hemoglobin), which are not the result of an averaging process.

Lavender essential oil from the aerial parts of Lavandula angustifolia Mill. was analyzed by GC-MS equipped with three capillary columns of different polarities, which were HP-1, HP-5 ms and HP-INNOWax. A total of 40 compounds were identified by GC-MS, accounting for 92.03% of the total essential oil compositions. Nineteen monomers were separated by column chromatography and improved preparative gas chromatography (pGC), six of which could not be retrieved from the NIST 14 (National Institute of Standards and Technology, USA; 14th edition) library database. Fifteen compounds were identified for the first time in lavender essential oil. The improved pGC not only doubled the efficiency but also greatly reduced the cost.