Chronopotentiometric Stripping Analysis of Mercury Using Glassy Carbon

U radu su definisani najznačajniji ekspirementalni faktori hronopotenciometrijske striping analize žive na staklastom ugljeniku. Poređeni su različiti elektrohemijski sistemi. Ispitani sistemi su obuhvatili klasičnu elektrohemijsku ćeliju sa stacionarnom disk elektrodom, sistem sa rotirajućom disk elektrodom, procesnu posudu od staklastog ugljenika kao radnuelektrodu i protočne sisteme uz tankoslojnu i tubularnu ćeliju. Tačnost definisanih metoda je potvrđena analizom standardnog referentnog materijala - lista paradajza. Najveća osetljivost određivanja žive je postignuta primenom procesne čaše od staklastog ugljenika kao radne elektrode. Granica detekcije je iznosila 0,10ng/dm3 žive(II). Razvijene metode su primenjene za određivanje žive u vodama. Uzorci voda su obuhvatili vode za piće, morske, rečne, bunarske, jezerske i otpadne vode.In this work optimal experimental conditions of chronopotentiometric stripping analysis of mercury using glassy carbon were investigated. Critical review of different electrochemical systems is given. Conventional electrochemical cell with stationary disc electrode, cell with rotating disc elektrode, system with process vessel as a working electrode and flow systems with thin-layer and tubular cell were encompassed by the investigation. Accuracy of the particular techniques was confirmed by analysing standard reference material - tomato leaves. Best sensitivity was achieved using process vessel of glassy carbon as a working electrode - 0,1 ng/d3. The developed methods were used for water analysis. Mercury was determined in samples of tap, well, seawater, river, lake, rain waters and in one sample of waste water

Subcritical water extraction of antioxidants from mountain germander (Teucrium montanum L.)

In the present work, antioxidant compounds from Teucrium montanum were extracted by subcritical water. The influence of extraction temperature and pressure on antioxidant activity of extracts has been investigated in terms of extraction yield (EY), total phenolic content (TPC), and DPPH-radical scavenging activity (DPPH-RSA) and ferric reducing antioxidant power (FRAP). Additionally, the compounds responsible for the antioxidant activity were identified and quantified by high performance liquid chromatography (HPLC). The highest EY (42.63%), TPC (174.61 ± 4.09 mg GAE/g DE) and antioxidant activity by DPPH-RSA (176.23 ± 8.76 mg TE/g DE) and FRAP (141.71 ± 5.21 mg AAE/g DE) were seen in extracts obtained at temperature of 160 °C and pressure of 10 bar. HPLC analysis revealed that naringin and gallic acid were the principle antioxidant compounds in subcritical extracts. According to the results, SWE has a great potential in exploitation of natural sources of bioactive compounds and production of pharmacologically-active fractions.The project 6818 – Transnational Cooperation, Agreement between Portugal (FCT) and Serbia (MSTD) is acknowledged. This work was also funded by project TR 31014 financially supported by the Serbian Ministry of Education, Science and Technological Development. Authors are also grateful for financial support from project NORTE-01-0145-FEDER-000011-311 Qualidade e Segurança Alimentar-uma abordagem (nano) tecnológica. The financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/QUI/50006/2013-POCI/01/0145/FEDER/007265, is also acknowledged. M.F. Barroso (SFRH/BPD/78845/2011) and Manuela M. Moreira (SFRH/BPD/97049/2013) are grateful to Fundação para a Ciência e Tecnologia for their postdoctoral fellowships.info:eu-repo/semantics/publishedVersio

Ispitivanje kvaliteta podzemnih, izvorskih i rečnih voda sa područja jugoistočne Srbije

The study deals with mineral characterisation of natural waters from South-East Serbia. The contents of aluminium, arsenic, calcium, cadmium, cobalt, chromium, cooper, iron, potassium, magnesium, manganese, sodium, nickel, lead and zinc were analysed in spring, ground and river waters by inductively coupled plasma-atomic emission spectrometry (ICPAES) technique. The study area was in the Southern Serbia, and included slopes of Rtanj, Ozren, Bukovik, Vrdenik and Čemernik mountains, and the valley of South Morava. Obtained contents were compared with Serbian regulations on the quality of water for human use, and directive of World Health Organization (WHO) for maximum allowed concentrations of chemical substances. High contents of macro-elements, namely calcium, magnesium and potassium, were detected in several spring and ground water samples which are believed to be due to direct influence of rock minerals. Some water samples contained iron, manganese and copper in concentration up to 168.3, 8.10 and 14.9 μg dm-3, respectively, but within the permissible limits. Other heavy metals were not detected in analysed samples. Based on the derived results, tested ground and spring water samples have significant potential to be used as sources for the production of bottled water, but further investigations are necessary. Additional investigations have to be focused on complete physical, chemical and microbiological assessments of water resources. Systematic hydrogeological assessment also should be performed in all seasons. In the meantime, precautionary measures should be immediately taken to protect and preserve these water resources.Ovaj rad predstavlja analizu kvaliteta prirodnih voda iz jugoistočne Srbije. Sadržaj arsena, aluminijuma, kalcijuma, kadmijuma, kobalta, hroma, bakra, gvožđa, kalijuma, magnezijuma, mangana, natrijuma, nikla, olova i cinka je određivan u izvorskim i podzemnim vodama, kao i u rečnoj vodi. Analiza navedenih elemenata je izvedena ICP-AES tehnikom. Analizirani su uzorci voda iz oblasti jugoistočne Srbije, uključujući područja planine Rtnja, Ozrena, Bukovika, Vrdenika i Čemernika, kao i područje doline reke Južne Morave. Određeni sadržaji analiziranih elemenata su poređeni sa važećim pravilnicima Republike Srbije i preporukama Svetske zdravstvene organizacije (SZO). Visoki sadržaj makro-elemenata, odnosno kalcijuma, magnezijuma i kalijuma uočeni su u izvorskim i nekoliko uzoraka podzemnih voda, što može biti posledica direktnog uticaja magmatskih stena. Pojedini uzorci voda su sadržali nešto više sadržaje gvožđa, mangana i bakra u koncentraciji do 168,3, 8,10 i 14,9 μg dm-3, redom, ali u granicama propisanim Pravilnikom i u skladu da preporukama SZO. Ostali teški metali nisu detektovani u ispitivanim uzorcima. Na osnovu dobijenih rezultata se može zaključiti da testirani uzorci podzemnih i izvorskih voda imaju značajan potencijal u smislu proizvodnje flaširane vode, uz neophodna dodatna istraživanja. Dodatna istraživanja bi trebalo usmeriti na kompletnu hemijsku analizu i ispitivanje fizičkih i mikrobioloških karakteristika uzoraka voda. Pored toga, neophodno je sprovesti sistematsko hidrogeološko ispitivanje izdašnosti podzemnih i izvorskih voda tokom svih godišnjih doba. U međuvremenu treba preduzeti mere predostrožnosti kako bi se ovi vodeni resursi zaštitili i očuvali

Vine-Canes as a Source of Value-Added Compounds for Cosmetic Formulations

The majority of works about vine-canes are focused on the evaluation of their chemical composition and antioxidant potential. To the best of our knowledge, the possible applications of produced extracts in cosmetic formulations have never been explored. The aim of the present study was to evaluate the antioxidant properties of vine-canes subcritical water extracts for use as active ingredients in the cosmetic industry. For that, the phenolic content and antioxidant activity of six vine-cane varieties, namely Alvarinho and Loureiro from the Minho region and Touriga Nacional and Tinta Roriz (TR) from both the Douro and Dão regions, were evaluated through spectrophotometric and chromatographic methods. All extracts presented similar antioxidant activity and the highest phenolic content was reported for TR variety from the Douro region (33.7 ± 1.9 mg GAE/g dw). The capacity of vine-cane extracts to capture reactive oxygen species superoxide (O2∙−) was also studied, with the highest IC50 value being obtained for Loureiro variety (56.68 ± 2.60 µg/mL). Furthermore, no adverse effects on HaCaT and HFF-1 dermal cell lines in concentrations below 100 and 1000 μg/mL, respectively, were determined. Finally, Loureiro vine-cane extract was incorporated into a topical formulation, and physical and microbiological properties were within expected values, demonstrating that vine-canes extracts can be successfully incorporated in cosmetic products.Funding This research was funded by FCT/MCTES through national funds (UIDB/50006/2020) and by the Applied Molecular Biosciences Unit - UCIBIO which is financed by national funds from FCT (UIDB/04378/2020). This work was also financed by the FEDER Funds through the Operational Competitiveness Factors Program - COMPETE and by National Funds through FCT within the scope of the project “PTDC/BII-BIO/30884/2017 - POCI-01-0145-FEDER-030884” and project “PTDC/ASP-AGR/29277/2017- POCI-01-0145-FEDER-029277”. Acknowledgments M.M.M. (project CEECIND/02702/2017) is grateful for the financial support financed by national funds through FCT—Fundação para a Ciência e a Tecnologia, I.P. and to REQUIMTE/LAQV. O.D. is thankful for the research grant from project PTDC/BII-BIO/30884/2017—POCI-01-0145-FEDER-030884. D.P. is thankful for the PhD grant (SFRH/BD/144534/2019) financed by POPH-QREN and subsidised by the European Science Foundation and Ministério da Ciência, Tecnologia e Ensino Superior. The supply of the vineyard pruning is acknowledged to Sogrape Vinhos, S.A.info:eu-repo/semantics/publishedVersio

Bioactive compounds of sweet and sour cherry stems obtained by subcritical water extraction

BACKGROUND Sweet cherries (Prunus avium L.) and sour cherries (Prunus cerasus L.) contain substantial amounts of anthocyanins and polyphenolics, and their stems have been used in traditional medicine for centuries. However, comparative data on the composition of sweet and sour cherry stems using the same analytical methodologies are limited. Moreover, there is no data in terms of biological activity of subcritical water extracts of cherry stems. RESULTS AND DISSCUSION Results obtained by using several assays that focused on different mechanisms showed that subcritical water extracts of sour and sweet cherry stems were powerful antiradicals and antioxidants. Anti‐proliferative properties measured by MTT (3‐[4,5‐ dimethylthiazol‐2‐yl]‐2,5 diphenyl tetrazolium bromide) test showed prominent cytotoxicity against different tumor cell lines. Inhibitory concentrations obtained were in the range 8.38–11.40 µg mL‐1. GC–MS (gas chromatography mass spectrometry) analysis showed the presence of alcohols, fatty acids, organic acids and other organic compounds. However, the chemical compositions of the two samples observed were similar, indicating similar chemical composition of sour and sweet cherry stems. CONCLUSION Subcritical water extracts of cherry stem demonstrated excellent biological activity and the potential to be used for pharmaceuticals or supplements due to confirmed high antioxidant, antiradical and antitumor activity.The authors are grateful to the Serbian Ministry of Education, Science and Technological Development (TR 31014 and bilateral project with Portugal), and Portuguese Ministry of Science (FCT/Servia 2015/2016 proc. 441.00 SERVIA). Financial support from the ‘Ministerio de Economía y Competitividad’ (Spanish Government) through the grant CTQ2016-77155-R is also gratefully acknowledged. R. Suárez thanks the Conselleria d’Educació, Cultura I Universitats from the Government of the Balearic Islands for a PhD stipend co-financed by Fondo Social Europeo (FPI/1444/2012). S. Clavijo acknowledges to Torres Quevedo Program of MINECO co-financed by European Funds, for the financial support through the PTQ 15-08038. A. Carvalho acknowledges program Norte-01-0145-FEDER-000011info:eu-repo/semantics/publishedVersio

Mineral Composition of Subcritical Water Extracts of Saccorhiza Polyschides, a Brown Seaweed Used as Fertilizer in the North of Portugal

The present work aimed at studying Saccorhiza polyschides extracts obtained by subcritical water extraction as a potential source of essential macro and trace elements, aiming for its potential application as a biofertilizer. The mineral composition, as well as sulfate, chlorine and iodine, total organic matter, and total nitrogen content, were determined on the extracts obtained from seaweeds harvested during low tide at the northern Portuguese coast. The selected parameters are important for a biofertilizer. Among the macronutrients, the most abundant was K (15.7 ± 0.2 g/L), followed by Na (5.46 ± 0.11 g/L), S (1.52 ± 0.06 g/L), Ca (1.09 ± 0.11 g/L), and Mg (1.02 ± 0.08 g/L). Several important micronutrients (Zn, B, Cl, P, Mo, V, Se, and I) have also been found in the extracts. The total organic matter was 34.1 ± 0.3 g/L. The extracts present low levels of toxic compounds such as Ni, Cd, and Pb. Considering the composition of the obtained extracts, these can find application in the development of fertilization products. The composition of subcritical water extracts of S. polyschides suggests that they may have important characteristics as a biofertilizer and can be an option in biofortification experiments with essential nutrients. The method can be easily scaled up which makes it attractive for agricultural applications.info:eu-repo/semantics/publishedVersio

Microwave-assisted extraction of phenolic compounds from Morus nigra leaves: optimization and characterization of the antioxidant activity and phenolic composition

BACKGROUND Morus nigra (mulberry) fruit has been reported as a source of bioactive compounds, although information about their leaves is very limited. Usually, they are considered wastes and have been traditionally used only for tea preparation. The main objective of this work was to explore the valorization of mulberry leaves by polyphenols microwave‐assisted extraction (MAE) and characterization of their antioxidant activity and phenolic composition. A 23 factorial design combined with response surface methodology were applied to characterize the effect of main microwave parameters on total phenolic content (TPC). RESULTS The optimized MAE conditions were 20 mL of ethanol:water (1:1; v/v), 120 °C, 28 min, 0.414 g and medium stirring speed. Under these conditions, TPC was 19.7 ± 2.0 mg gallic acid equivalents (GAE) g‐1 dry plant (DP), and antioxidant activity was 15.3 ± 1.0 mg ascorbic acid (AA) g‐1 DP (ferric reduction activity power –FRAP– assay), 18.6 ± 1.3 mg Trolox equivalents (TE) g‐1 DP (2,2‐diphenyl‐1‐picrylhydrazyl –DPPH– assay) and 186 ± 15 mg TE g‐1 DP (oxygen radical absorbance capacity –ORAC– assay). When compared with ultrasound extraction and Pharmacopeia reference method, MAE was more efficient, representing a valuable technology. Of the 13 compounds identified by HPLC, the most abundant were rutin, chlorogenic, β‐resorcylic and caffeic acids. CONCLUSION These results indicate that mulberry leaves are of potential interest for agro‐food industries as a new source of natural antioxidants.This investigation is a part of the postdoctoral research by Marija Radojkovic, and she is grateful for financial support by ´the Serbian Ministry of Education, Science and Technological Development (Project No. TR 31013); the project 6818 - Transnational Cooperation Agreement between Portugal (FCT) and Serbia (MSTD) is also acknowledged. Authors are also grateful for financial support from project NORTE-01-0145-FEDER-000011 –311 Qualidade e Segurança Alimentar – uma abordagem (nano) tecnológica. The financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/ QUI/50006/2013 - POCI/01/0145/FERDER/007265, is also acknowledged. M. F. Barroso (SFRH/BPD/78845/2011) and Manuela M. Moreira (SFRH/BPD/97049/2013) are grateful to Fundação para a Ciência e Tecnologia for their postdoctoral fellowships.info:eu-repo/semantics/publishedVersio

Deaeration method for imidacloprid determination on glassy carbon electrode.

In this work deaeration methods were investigated for chronopotentiometric determination of pesticide imidacloprid [1-(6-chloro-3-pyridyimethyl)-N-nitroimidazolidin-2-ylideneamine] on glassy carbon electrode. As a supporting electrolyte, a Britton-Robinson buffer was used. All investigations were carried out in model systems. Cathodic peak of imidacloprid could not be registered only in BrittonRobinson buffer, due to electrochemical reduction of dissolved oxygen. For this reason, it was necessary to investigate different deaeration methods for removing oxygen from the solution. Within this, deaerations by various reductants and by passing a nitrogen stream were compared. Investigated reductants were sodium sulfite, ascorbic acid, oxalic acid, potassium bromide and sodium bromide. Combinations of a certain reductant and nitrogen were compared as well. Addition of a saturated solution of sodium sulfite directly in the tested solution proved as the best deaeration method. This method provided fast deaeration step as it took less than a minute for completely removing the oxygen. An optimal concentration of the solution of sodium sulfite was also investigated. Concentrations of sodium sulfite were tested in the range of 0.6 g/idm* to 230 gidm?. Considering the height of the analytical signal and its reproducibility, concentration of 8.8 gldm? showed as optimal. This method could be applied for the determination of imidacloprid in commercial formulations and some real samples

Development and Characterization of Functional Cookies Enriched with Chestnut Shells Extract as Source of Bioactive Phenolic Compounds

Chestnut (Castanea sativa) shells (CSs), an undervalued agro-industrial biowaste, have arisen as a source of bioactive compounds with promising health-promoting effects. This study attempted, for the first time, to develop a functional food, namely cookies, using a CS extract obtained by an eco-friendly technology (subcritical water extraction). The cookies were characterized regarding their nutritional composition, total phenolic and flavonoid contents (TPC and TFC, respectively), antioxidant/antiradical activities, phenolic profile, and sensory evaluation. The results demonstrated that the CS-extract-enriched cookies were mainly composed of carbohydrates (53.92% on dry weight (dw)), fat (32.62% dw), and fiber (5.15% dw). The phenolic profile outlined by HPLC-PDA revealed the presence of phenolic acids, flavonoids, and hydrolysable tannins, attesting to the high TPC and TFC. The in vitro antioxidant/antiradical effects proved the bioactivity of the functional cookies, while the sensory evaluation unveiled excellent scores on all attributes (≥6.25). The heatmap diagram corroborated strong correlations between the TPC and antioxidant/antiradical properties, predicting that the appreciated sensory attributes were closely correlated with high carbohydrates and phenolic compounds. This study encourages the sustainable recovery of antioxidants from CSs and their further employment as an active nutraceutical ingredient in functional cookies.This work received financial support from national funds (UIDB/50006/2020), project PTDC/ASP-AGR/29277/2017-Castanea sativa shells as a new source of active ingredients for Functional Food and Cosmetic applications: a sustainable approach, and project 5537 DRI, Sérvia 2020/21 from the Portuguese-Serbia Bilateral Cooperation-Development of functional foods, incorporating a chestnut shell extract obtained by subcritical water, supported by national funds by FCT/MCTES and co-supported by Fundo Europeu de Desenvolvimento Regional (FEDER) throughout COMPETE 2020-Programa Operacional Competitividade e Internacionalização (POCI-01-0145-FEDER-029277). Authors also thanks the project SYSTEMIC “an integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition“. The Knowledge hub on Nutrition and Food Security, has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI launched in 2019 under the ERA-NET ERA- HDHL (n◦ 696295). Jaroslava Švarc-Gajić and Tanja Brezo-Borjan are grateful to the Science Fund of the Republic of Serbia (Grant No. 7747845, In situ pollutants removal from waters by sustainable green nanotechnologies—CleanNanoCatalyze), and to the Ministry of education, science and technological development of the Republic of Serbia (Grant No 451-03-68/2020–14/200134).The authors kindly thank Sortegel (Sortes, Portugal) for the samples. Diana Pinto (SFRH/BD/144534/2019) is thankful for her Ph.D. grant financed by FCT/MCTES and POPH-QREN and supported by funds from European Union (EU) and Fundo Social Europeu (FSE) through Programa Operacional Regional Norte. Francisca Rodrigues (CEECIND/01886/2020), Elsa F. Vieira (CEECIND/03988/2018), and Manuela M. Moreira (CEECIND/02702/2017) are thankful for their contracts financed by FCT/MCTES—CEEC Individual 2020 Program Contract. Anna Vallverdú-Queralt thanks the Spanish Ministerio de Ciencia, Innovación y Universidades for the Ramon y Cajal contract (RYC-2016-19355). The authors kindly thank Sortegel (Sortes, Portugal) for the samples. Diana Pinto (SFRH/BD/144534/2019) is thankful for her Ph.D. grant financed by FCT/MCTES and POPHQREN and supported by funds from European Union (EU) and Fundo Social Europeu (FSE) through Programa Operacional Regional Norte. Francisca Rodrigues (CEECIND/01886/2020), Elsa F. Vieira (CEECIND/03988/2018), and Manuela M. Moreira (CEECIND/02702/2017) are thankful for their contracts financed by FCT/MCTES—CEEC Individual 2020 Program Contract. Anna VallverdúQueralt thanks the Spanish Ministerio de Ciencia, Innovación y Universidades for the Ramon y Cajal contract (RYC-2016-19355).info:eu-repo/semantics/publishedVersio

Potential of Portuguese vine shoot wastes as natural resources of bioactive compounds

Since annually a high amount of wastes is produced in vine pruning, the aim of this study was to evaluate the potential of vine shoots from two Portuguese grape varieties (Touriga Nacional - TN and Tinta Roriz - TR) to be used as a natural source of phenolic compounds. To reach this goal, three techniques were explored, namely microwave-assisted extraction (MAE), subcritical water extraction (SWE) and conventional extraction (CE). The phenolic composition of the extracts, antioxidant and biological activities were evaluated by spectrophotometry and chromatography. MAE and SWE produced the highest concentrated extracts. TR vine shoot variety had the highest antioxidant activity and total phenolic (32.1±0.9mggallicacidequivalents/g dry sample), as well as flavonoid content (18.7±1.2mgepicatechinequivalents/g dry sample). For the first time, the biological activity of the vine shoot extracts was tested. Results demonstrated that all of them had antimicrobial potential against different bacteria and yeasts, and the ability of inhibiting α-amylase and acetylcholinesterase enzymes, with MAE TR extracts being the most efficient. HPLC analysis enabled the identification of different phenolic compounds, with gallic acid, catechin, myricetin and kaempferol-3-O-rutinoside being the main contributors to the phenolic composition. Portuguese vine shoot wastes could serve as easily accessible source of natural antioxidants for the food or pharmaceutical industries.Manuela M. Moreira (SFRH/BPD/97049/2013) and M. F. Barroso (SFRH/BPD/78845/2011) are grateful for the postdoctoral fellowships financed by POPH-QREN – Tipologia 4.1 – Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior. The authors are also grateful for the financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265; the project 6818 - Transnational Cooperation, Agreement between Portugal (FCT) and Serbia (MSTD) is also acknowledged. This work was also supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI). The supply of the vine shoots is acknowledged to Sogrape Vinhos, S.A.info:eu-repo/semantics/publishedVersio