Simultaneous identification and quantification of three water-soluble polymers (PVP, PNVCL and PEI) in wastewater samples by continuous-flow off-line pyrolysis GC/MS.

In environmental analysis, the detection of water-soluble synthetic polymers (WSSP) presents considerable challenges. Thus, a precise and reproducible analytical method was developed using continuous-flow off-line pyrolysis with gas chromatography/mass spectrometry (GC/MS) to simultaneously identify multiple water-soluble polymers from a single environmental sample. WSSP are widely used in multiple industries as hydrogels due to their hydrophilic character and potential biocompatibility. This adaptability of hydrogels is reflected in their ability to provide customized formulations for specific needs, such as in the development of personal care products, medicine, and pharmaceuticals. Specifically, polyvinylpyrrolidone (PVP), poly(N-vinylcaprolactam) (PNVCL), and polyethyleneimine (PEI) were targeted for analysis in wastewater, employing unique pyrolysis products for identification. These polymers require careful assessment in wastewater to evaluate potential environmental risks associated with their release. PVP and PNVCL were identified through two pyrolysis products, while six pyrolysis products were utilized for the identification of PEI. The validated method demonstrated very good linearity and reproducibility, with correlation coefficients ranging from 0.94 to 0.99 and relative standard deviation (RSD) values between 3 % and 36 % for the targeted compounds. The limit of quantification (LOQ) for the three polymers ranged from 1 to 10 µg L-1. Moreover, the average recovery rates for these polymers, determined from artificial water samples, were approx. 85 %. Utilizing the validated method, water samples from seven wastewater treatment plants in Germany were successfully analyzed, confirming the presence of these polymers at elevated concentrations in the µg L-1 range. Notably, untreated influent waters exhibited higher polymer levels compared to treated influents and effluents, underscoring their significant contribution to overall polymer content. The developed analytical method provides an efficient tool for the simultaneous identification and quantification of PVP, PNVCL, and PEI in wastewater samples. The results highlighted the prevalent presence of PVP, PNVCL, and PEI in the tested wastewater samples, indicating their significant abundance.

Effect of Beetroot Powder Incorporation on Functional Properties and Shelf Life of Biscuits.

The demand for ready-to-use functional foods is high, which encourages manufacturers to develop new, nutritionally valuable products. As an excellent source of biologically active compounds, beetroot (Beta vulgaris L.) is considered to have highly beneficial effects on health. This research aimed to evaluate the impact of replacing spelt flour (SF) with 15%, 20% and 25% beetroot powder (BP). The physicochemical and functional properties of biscuits baked at different temperatures (150 and 170 °C) were followed at the beginning, and after 3 and 6 months of storage as standard conditions. Moisture content and water activity (aw) gave insight into the biscuits' shelf life. The value of aw from 0.35 to 0.56 indicated appropriate storability. Dietary fiber content in fresh biscuits ranged from 6.1% to 7.6%, protein from 9.2% to 8.9% and sugar from 30.6% to 35.9%. The content of betalain, total polyphenols and flavonoids, and antioxidant activity (DPPH, FRAP) increased with beetroot powder content incorporated. A slight decrease of all the mentioned parameters during the storage indicated satisfied retention of bioactive molecules. The content of prevalent phenolic compounds gallic and protocatechuic acid, identified by HPLC, decreased from 22.2-32.0 and 21.1-24.9 in fresh biscuits to 18.3-23.4 and 17.3-20.3 mg/100 g upon six months of storage, respectively. An increase of the L* and a* and a decrease of the b* coordinate values, compared with the control sample without beetroot values, was noticed as well as the expected level of their change during the storage. The obtained results indicated that biscuits enriched with beetroot powder showed a significantly improved functional, nutritional and antioxidant potential during storage.

Determination of toxic elements in meat products from Serbia packaged in tinplate cans.

This work aimed to examine the influence of the storage period on the content of toxic elements (As, Cd, Hg, and Pb) in five types of canned meat products regularly used in the Serbian Armed Forces. Cans of beef goulash (BG), pork ragout (PR), spam (SP), liver pate (LP), and meatballs in tomato sauce (MB), produced according to military standards and stored under regular conditions, were analyzed. Meat products were packed in tin cans made according to special requirements in terms of tin and varnish application and stored for up to 6 years. The content of toxic elements varied depending on the analyzed product. The highest average content of arsenic was in BG (10.00 µg/kg), cadmium in LP (35.91 µg/kg), and mercury and lead in PR (15.04 and 8.00 µg/kg, respectively). The average concentrations of As, Cd, Hg, and Pb in all types of canned meat products were significantly lower than the maximum permitted levels in food currently in force by local and EU legislation. The storage period did not significantly affect the level of toxic elements, although higher concentrations were found in samples stored for more than 2 years. Examination of raw materials, spices, and additives showed that the highest Cd and Pb concentrations, which can affect the total level of these elements in meat products, were found in red ground pepper (Cd above 150 µg/kg) and dish supplement (Pb of 250 µg/kg). The assessment of the weekly intake of toxic elements through canned meat showed that it is significantly lower than the values that affect adversely to human health, as determined by the FAO/WHO and EFSA. However, as there is a constant possibility of contamination of raw materials and food additives, primarily due to environmental pollution, it is recommended to monitor the content of heavy metals in food permanently and assess their risk to human health.

Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells.

Polyurethane copolymers based on α,ω-dihydroxypropyl poly(dimethylsiloxane) (PDMS) with a range of soft segment contents were prepared by two-stage polymerization, and their microstructures, thermal, thermomechanical, and surface properties, as well as in vitro hemo- and cytocompatibility were evaluated. All utilized characterization methods confirmed the existence of moderately microphase separated structures with the appearance of some microphase mixing between segments as the PDMS (i.e., soft segment) content increased. Copolymers showed higher crystallinity, storage moduli, surface roughness, and surface free energy, but less hydrophobicity with decreasing PDMS content. Biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact, an extraction method and after pretreatment of copolymers with multicomponent protein mixture, as well as by a competitive protein adsorption assay. Copolymers showed no toxic effect to endothelial cells and all copolymers, except that with the lowest PDMS content, exhibited resistance to endothelial cell adhesion, suggesting their unsuitability for long-term biomedical devices which particularly require re-endothelialization. All copolymers exhibited excellent resistance to fibrinogen adsorption and adsorbed more albumin than fibrinogen in the competitive adsorption assay, suggesting their good hemocompatibility. The noncytotoxic chemistry of these synthesized materials, combined with their nonadherent properties which are inhospitable to cell attachment and growth, underlie the need for further investigations to clarify their potential for use in short-term biomedical devices.

In vitro biocompatibility evaluation of novel urethane-siloxane co-polymers based on poly(ϵ-caprolactone)-block-poly(dimethylsiloxane)-block-poly(ϵ-caprolactone).

Novel polyurethane co-polymers (TPUs), based on poly(ϵ-caprolactone)-block-poly(dimethylsiloxane)-block-poly(ϵ-caprolactone) (PCL-PDMS-PCL) as soft segment and 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) as hard segment, were synthesized and evaluated for biomedical applications. The content of hard segments (HS) in the polymer chains was varied from 9 to 63 wt%. The influence of the content and length of the HS on the thermal, surface, mechanical properties and biocompatibility was investigated. The structure, composition and HS length were examined using (1)H- and quantitative (13)C-NMR spectroscopy. DSC results implied that the synthesized TPUs were semicrystalline polymers in which both the hard MDI/BD and soft PCL-PDMS-PCL segments participated. It was found that an increase in the average HS length (from 1.2 to 14.4 MDI/BD units) was accompanied by an increase in the crystallinity of the hard segments, storage moduli, hydrophilicity and degree of microphase separation of the co-polymers. Depending on the HS content, a gradual variation in surface properties of co-polymers was revealed by FT-IR, AFM and static water contact angle measurements. The in vitro biocompatibility of co-polymers was evaluated using the endothelial EA.hy926 cell line and protein adsorption on the polyurethane films. All synthesized TPUs adsorbed more albumin than fibrinogen from multicomponent protein mixture, which may indicate biocompatibility. The polyurethane films with high HS content and/or high roughness coefficient exhibit good surface properties and biocompatible behavior, which was confirmed by non-toxic effects to cells and good cell adhesion. Therefore, the non-cytotoxic chemistry of the co-polymers makes them good candidates for further development as biomedical implants.