Matija Sambol, K. Ester, A. Husak, Đ. Škalamera, I. Piantanida, N. Basarić
New bifunctional quinone methide (QM) precursors, bisphenols 2a–2e, and monofunctional QM precursor 7 were synthesized. Upon treatment with fluoride, desilylation triggers formation of reactive intermediates, QMs, which was demonstrated by trapping QM with azide or methanol. The ability of QMs to alkylate and cross-link DNA was assayed by investigation of the effects of QMs to DNA denaturing, but without conclusive evidence. Furthermore, treatment of a plasmid DNA with compounds 2a–2e and KF, followed by the analysis by alkaline denaturing gel electrophoresis, did not provide evidence for the DNA cross-linking. MTT test performed on two human cancer cell lines (MCF7 breast adenocarcinoma and SUM159 pleomorphic breast carcinoma), with and without fluoride, indicated that 2a–2e or the corresponding QMs did not exhibit cytotoxic activity, in line with the lack of ability to cross-link DNA. The lack of reactivity with DNA and biological activity were explained by sequential formation of QMs where bifunctional cytotoxic reagent is probably never produced. Instead, the sequential generation of monofunctional QM followed by a faster hydrolysis leads to the destruction of biologically active reagent. The findings described here are particularly important for the rational design of new generation of QM precursor molecules that will attain desirable DNA reactivity and cytotoxicity.
{"title":"Bifunctional Phenol Quinone Methide Precursors: Synthesis and Biological Activity","authors":"Matija Sambol, K. Ester, A. Husak, Đ. Škalamera, I. Piantanida, N. Basarić","doi":"10.5562/CCA3455","DOIUrl":"https://doi.org/10.5562/CCA3455","url":null,"abstract":"New bifunctional quinone methide (QM) precursors, bisphenols 2a–2e, and monofunctional QM precursor 7 were synthesized. Upon treatment with fluoride, desilylation triggers formation of reactive intermediates, QMs, which was demonstrated by trapping QM with azide or methanol. The ability of QMs to alkylate and cross-link DNA was assayed by investigation of the effects of QMs to DNA denaturing, but without conclusive evidence. Furthermore, treatment of a plasmid DNA with compounds 2a–2e and KF, followed by the analysis by alkaline denaturing gel electrophoresis, did not provide evidence for the DNA cross-linking. MTT test performed on two human cancer cell lines (MCF7 breast adenocarcinoma and SUM159 pleomorphic breast carcinoma), with and without fluoride, indicated that 2a–2e or the corresponding QMs did not exhibit cytotoxic activity, in line with the lack of ability to cross-link DNA. The lack of reactivity with DNA and biological activity were explained by sequential formation of QMs where bifunctional cytotoxic reagent is probably never produced. Instead, the sequential generation of monofunctional QM followed by a faster hydrolysis leads to the destruction of biologically active reagent. The findings described here are particularly important for the rational design of new generation of QM precursor molecules that will attain desirable DNA reactivity and cytotoxicity.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3455","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46510267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon steel corrodes severely in presence of sodium chloride and it needs additional protection to be used in marine environments. This work investigates the possibility of using a layer of stearic acid as protection for carbon steel. Stearic acid was applied on the steel by two types of treatments: chemical preparation - by immersion of a steel sample in the SA solution and electrochemical preparation – by imposing a corresponding potential to the system. The results have shown that although both treatments result in obtaining an ordered aliphatic monolayer and both treatments increase the hydrophobicity of the surface, protection that the electrochemical preparation offers is stable in time, while the protection the chemical preparation offers is not.
{"title":"Self-Assembling Monolayers of Stearic Acid in Protection of Steel","authors":"Katarina Marušić, H. O. Ćurković","doi":"10.5562/CCA3436","DOIUrl":"https://doi.org/10.5562/CCA3436","url":null,"abstract":"Carbon steel corrodes severely in presence of sodium chloride and it needs additional protection to be used in marine environments. This work investigates the possibility of using a layer of stearic acid as protection for carbon steel. Stearic acid was applied on the steel by two types of treatments: chemical preparation - by immersion of a steel sample in the SA solution and electrochemical preparation – by imposing a corresponding potential to the system. The results have shown that although both treatments result in obtaining an ordered aliphatic monolayer and both treatments increase the hydrophobicity of the surface, protection that the electrochemical preparation offers is stable in time, while the protection the chemical preparation offers is not.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"427-433"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48403495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The accurate and precise characterization of eight chlorogenic acids (CGAs) isomers, caffeoylquinic acids (5-CQA, 4-CQA, 3-CQA), dicaffeoylquinic acids (3, 5-diCQA, 4, 5-diCQA, 3, 4-diCQA), and feruloylquinic acids (5-FQA, 4- FQA), was carried out using different brands of coffee. High-performance liquid chromatography (HPLC), differential pulse (DPV) and square- wave voltammetry (SWV) were applied for the investigation. HPLC proved to be an accurate and precise method for separation, identification and quantification of CGAs isomers in coffee extracts. DPV and SWV have shown that electrochemical behaviour of coffee extracts was very similar to that of CGAs isomers and DPV and SWV can be used for the correct characterization of CGAs in coffee. All three techniques have shown a very high correlation of CGAs content in all investigated coffee samples. Therefore, HPLC, DPV and SWV methods can be used in combination as very selective, sensitive and precise methods for characterization of CGAs isomers in coffee extracts.
{"title":"Chromatographic and voltammetric characterization of chlorogenic acids in coffee samples","authors":"I. Tomac, L. Jakobek, M. Šeruga","doi":"10.5562/CCA3439","DOIUrl":"https://doi.org/10.5562/CCA3439","url":null,"abstract":"The accurate and precise characterization of eight chlorogenic acids (CGAs) isomers, caffeoylquinic acids (5-CQA, 4-CQA, 3-CQA), dicaffeoylquinic acids (3, 5-diCQA, 4, 5-diCQA, 3, 4-diCQA), and feruloylquinic acids (5-FQA, 4- FQA), was carried out using different brands of coffee. High-performance liquid chromatography (HPLC), differential pulse (DPV) and square- wave voltammetry (SWV) were applied for the investigation. HPLC proved to be an accurate and precise method for separation, identification and quantification of CGAs isomers in coffee extracts. DPV and SWV have shown that electrochemical behaviour of coffee extracts was very similar to that of CGAs isomers and DPV and SWV can be used for the correct characterization of CGAs in coffee. All three techniques have shown a very high correlation of CGAs content in all investigated coffee samples. Therefore, HPLC, DPV and SWV methods can be used in combination as very selective, sensitive and precise methods for characterization of CGAs isomers in coffee extracts.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"501-511"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43923758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Slađana Strmečki, I. Ciglenečki, M. G. Udovič, M. Marguš, E. bura-Nakić, J. Dautović, M. Plavšić
The increased amount of organic matter (OM) accompanied with the development of hypoxia/anoxia and appearance of the sulphur species are indicators of eutrophication in natural waters. To predict biogeochemical and ecological changes, specific OM components in the Lake Brljan (the karst Krka River, Croatia ; station B and station B2 downstream) were studied during 2011 and in January 2012 using voltammetry. Surface‒active substances (eq. 0.018 to 0.150 mg dm-3 Triton‒X‒100) and Cu complexing capacity (54‒680 nmol dm-3) showed the highest values in surface water layer in May 2011 (B) and in November 2011 (B2), associated with the highest dissolved (0.505‒ 1.530 mg C dm-3) and particulate (0.051‒0.725 mg C dm-3) organic carbon and phytoplankton biomass. Autochthonously produced OM did not cause hypoxia/anoxia during the investigated period. Brljan's lake water could be characterised as oligotrophic with occasionally elevated OM concentration depending on season and Krka River water regime.
有机质（OM）含量的增加伴随着缺氧/缺氧的发展和硫物种的出现是天然水体富营养化的指标。为了预测生物地球化学和生态变化，在2011年和2012年1月使用伏安法研究了布尔詹湖（克罗地亚喀斯特Krka河；B站和B2站下游）的特定OM成分。2011年5月（B）和11月（B2）地表水层中的表面活性物质（当量0.018至0.150 mg dm-3 Triton-X-100）和Cu络合容量（54至680 nmol dm-3）显示出最高值，与最高的溶解（0.505至1.530 mg C dm-3）和颗粒（0.051至0.725 mg C dm3）有机碳和浮游植物生物量有关。在研究期间，本地产生的OM不会引起缺氧/缺氧。Brljan的湖水可以被描述为贫营养的，根据季节和Krka河的水情，OM浓度偶尔会升高。
{"title":"Voltammetric study of organic matter components in the upper reach of the Krka River, Croatia","authors":"Slađana Strmečki, I. Ciglenečki, M. G. Udovič, M. Marguš, E. bura-Nakić, J. Dautović, M. Plavšić","doi":"10.5562/CCA3443","DOIUrl":"https://doi.org/10.5562/CCA3443","url":null,"abstract":"The increased amount of organic matter (OM) accompanied with the development of hypoxia/anoxia and appearance of the sulphur species are indicators of eutrophication in natural waters. To predict biogeochemical and ecological changes, specific OM components in the Lake Brljan (the karst Krka River, Croatia ; station B and station B2 downstream) were studied during 2011 and in January 2012 using voltammetry. Surface‒active substances (eq. 0.018 to 0.150 mg dm-3 Triton‒X‒100) and Cu complexing capacity (54‒680 nmol dm-3) showed the highest values in surface water layer in May 2011 (B) and in November 2011 (B2), associated with the highest dissolved (0.505‒ 1.530 mg C dm-3) and particulate (0.051‒0.725 mg C dm-3) organic carbon and phytoplankton biomass. Autochthonously produced OM did not cause hypoxia/anoxia during the investigated period. Brljan's lake water could be characterised as oligotrophic with occasionally elevated OM concentration depending on season and Krka River water regime.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"447-454"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48941026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The first reception of Mendeleev's periodic table of elements and its first mention and publication in Croatian chemistry textbooks is explored. First
对门捷列夫元素周期表的首次接受及其在克罗地亚化学教科书中的首次提及和出版进行了探索。第一
{"title":"First appearance of Mendeleev's periodic system of elements in Croatian chemistry textbooks","authors":"V. Flegar, S. Inić","doi":"10.5562/CCA3437","DOIUrl":"https://doi.org/10.5562/CCA3437","url":null,"abstract":"The first reception of Mendeleev's periodic table of elements and its first mention and publication in Croatian chemistry textbooks is explored. First","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"543-549"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43563267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tatjana Mijošek, M. Erk, V. Marijić, N. Krasnići, Zrinka Dragun, D. Ivanković
Present study aims to improve the modified Brdicka procedure of metallothionein (MT) quantification in a way to reduce the analysis duration. Therefore, scan rate of the voltammetric sweep was increased from 0.0052 V s–1 to 0.013 V s–1 by lowering the duration of one step potential from 0.5 s to 0.2 s, which resulted in 2.5 times faster voltammetric sweep. Research confirmed high accuracy and reliability of MT measurements, in both standard sample and samples of heat-treated cytosols of liver, gills and the intestine of European chub and liver of brown trout. The method was confirmed as fast and reliable electrochemical technique for quantification of MTs and this time- saving improvement is especially useful and applicable in different biomonitoring studies which require the analyses of numerous biological samples and high sample throughput.
本研究旨在改进金属硫蛋白（MT）定量的改良Brdicka方法，以缩短分析时间。因此，通过将一步电位的持续时间从0.5 s降低到0.2 s，伏安扫描的扫描速率从0.0052 V s–1增加到0.013 V s–2，从而使伏安扫描速度快2.5倍。研究证实了MT测量的高准确性和可靠性，无论是在标准样品还是热处理的欧洲胖鱼肝脏、鳃和肠道的细胞溶质样品中，还是在褐鳟的肝脏中。该方法被证实是一种快速可靠的MT定量电化学技术，这种节省时间的改进在需要分析大量生物样品和高样品通量的不同生物监测研究中尤其有用和适用。
{"title":"Electrochemical Determination of Metallothioneins by the Modified Brdička Procedure as an Analytical Tool in Biomonitoring Studies","authors":"Tatjana Mijošek, M. Erk, V. Marijić, N. Krasnići, Zrinka Dragun, D. Ivanković","doi":"10.5562/CCA3444","DOIUrl":"https://doi.org/10.5562/CCA3444","url":null,"abstract":"Present study aims to improve the modified Brdicka procedure of metallothionein (MT) quantification in a way to reduce the analysis duration. Therefore, scan rate of the voltammetric sweep was increased from 0.0052 V s–1 to 0.013 V s–1 by lowering the duration of one step potential from 0.5 s to 0.2 s, which resulted in 2.5 times faster voltammetric sweep. Research confirmed high accuracy and reliability of MT measurements, in both standard sample and samples of heat-treated cytosols of liver, gills and the intestine of European chub and liver of brown trout. The method was confirmed as fast and reliable electrochemical technique for quantification of MTs and this time- saving improvement is especially useful and applicable in different biomonitoring studies which require the analyses of numerous biological samples and high sample throughput.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"475-480"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48908309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martina Mumelaš, H. O. Ćurković, D. Mikić, M. Hranjec, M. Cindrić
Seawater is a corrosive medium that adversely affects on the metallic structures. For that reason, it is often desirable to use some type of corrosion protection to extend the life of structures. The aim of this work was to examine the possibility of CuNi alloy protection in artificial seawater by four benzimidazole derivatives: 2-amino-5(6)nitrobenzimidazole, 2-amino-5-(6)-cyanobenzimidazole, 2-aminobenzimidazole, 2-amino-5(6)-(2-imidazolinyl)benzimidazole hydrochloride. The corrosion studies conducted by polarization measurements after 1 h of immersion in inhibitor solution showed that the most effective inhibitor is 2-amino-5(6)-nitrobenzimidazole. The electrochemical tests were also performed in time by the means of electrochemical impedance spectroscopy for the two most effective inhibitors. The surface of samples was analyzed by scanning electron microscopy and ATR-FTIR spectroscopy. It was concluded that the efficiency of studied inhibitors increases with prolonged exposure of the CuNi alloy to inhibitor solutions as well as with the increase of inhibitor concentration.
{"title":"Benzimidazole Derivatives as Copper Alloy Corrosion Inhibitors","authors":"Martina Mumelaš, H. O. Ćurković, D. Mikić, M. Hranjec, M. Cindrić","doi":"10.5562/cca3450","DOIUrl":"https://doi.org/10.5562/cca3450","url":null,"abstract":"Seawater is a corrosive medium that adversely affects on the metallic structures. For that reason, it is often desirable to use some type of corrosion protection to extend the life of structures. The aim of this work was to examine the possibility of CuNi alloy protection in artificial seawater by four benzimidazole derivatives: 2-amino-5(6)nitrobenzimidazole, 2-amino-5-(6)-cyanobenzimidazole, 2-aminobenzimidazole, 2-amino-5(6)-(2-imidazolinyl)benzimidazole hydrochloride. The corrosion studies conducted by polarization measurements after 1 h of immersion in inhibitor solution showed that the most effective inhibitor is 2-amino-5(6)-nitrobenzimidazole. The electrochemical tests were also performed in time by the means of electrochemical impedance spectroscopy for the two most effective inhibitors. The surface of samples was analyzed by scanning electron microscopy and ATR-FTIR spectroscopy. It was concluded that the efficiency of studied inhibitors increases with prolonged exposure of the CuNi alloy to inhibitor solutions as well as with the increase of inhibitor concentration.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"513-523"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45786792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martina Medvidović‐Kosanović, A. Stanković, Marija Jozanović, M. Drulak, Marina Ilić
In this work oxido-reduction properties of L-histidine were studied by cyclic and differential pulse voltammetry in a pH range from pH 4–10. The results have shown that L-histidine is not electroactive in a pH range from pH 4 to pH 9, while oxidation peak of L-histidine’s imidazole ring at pH 10 was detected with differential pulse voltammetry. It has been found that the oxidation peak current of L-histidine increased with the increase of its concentration in a solution. Adsorption of oxidation product of L-histidine on a glassy carbon electrode surface was also detected. Voltammetric techniques (cyclic and differential pulse voltammetry) and UV/VIS spectroscopy were used to study formation of L-histidine complexes with transition metals. It has been found that L-histidine formed octahedral complex with metal ion (Co2+ and Ni2+) in a 1 : 1 ratio.
{"title":"Electrochemical and UV/VIS Study of L-Histidine and Its Complexes with Cobalt and Nickel","authors":"Martina Medvidović‐Kosanović, A. Stanković, Marija Jozanović, M. Drulak, Marina Ilić","doi":"10.5562/CCA3423","DOIUrl":"https://doi.org/10.5562/CCA3423","url":null,"abstract":"In this work oxido-reduction properties of L-histidine were studied by cyclic and differential pulse voltammetry in a pH range from pH 4–10. The results have shown that L-histidine is not electroactive in a pH range from pH 4 to pH 9, while oxidation peak of L-histidine’s imidazole ring at pH 10 was detected with differential pulse voltammetry. It has been found that the oxidation peak current of L-histidine increased with the increase of its concentration in a solution. Adsorption of oxidation product of L-histidine on a glassy carbon electrode surface was also detected. Voltammetric techniques (cyclic and differential pulse voltammetry) and UV/VIS spectroscopy were used to study formation of L-histidine complexes with transition metals. It has been found that L-histidine formed octahedral complex with metal ion (Co2+ and Ni2+) in a 1 : 1 ratio.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"421-426"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45424273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gabrijela Radić, Ivan Šajnović, Željka Petrović, M. K. Roković
The composite hydrogel, composed of reduced graphene oxide and α-Fe2O3 fibres (rGO/α-Fe2O3), was successfully prepared by the hydrothermal procedure starting from GO and α-Fe2O3 nanofibres. According to the SEM and XRD results, α-Fe2O3 fibres are distributed between rGO sheets increasing the inter-sheet space. The rGO/α-Fe2O3 composite was tested as an active material in supercapacitor by means of cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscopy in 0.5 mol dm–3 Na2SO4. The obtained results confirmed a positive effect of the α-Fe2O3 addition on capacitive properties. Improved capacitive properties of the composite make this material suitable for supercapacitor application.
{"title":"Reduced Graphene Oxide/α-Fe2O3 Fibres as Active Material for Supercapacitor Application","authors":"Gabrijela Radić, Ivan Šajnović, Željka Petrović, M. K. Roković","doi":"10.5562/CCA3452","DOIUrl":"https://doi.org/10.5562/CCA3452","url":null,"abstract":"The composite hydrogel, composed of reduced graphene oxide and α-Fe2O3 fibres (rGO/α-Fe2O3), was successfully prepared by the hydrothermal procedure starting from GO and α-Fe2O3 nanofibres. According to the SEM and XRD results, α-Fe2O3 fibres are distributed between rGO sheets increasing the inter-sheet space. The rGO/α-Fe2O3 composite was tested as an active material in supercapacitor by means of cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscopy in 0.5 mol dm–3 Na2SO4. The obtained results confirmed a positive effect of the α-Fe2O3 addition on capacitive properties. Improved capacitive properties of the composite make this material suitable for supercapacitor application.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"481-490"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45163575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Ciglenečki, J. Dautović, Ana Cvitešić, G. Pletikapić
Electrochemical methods at the mercury electrode were used for monitoring production of surface active substances (SAS) and reduced sulfur species (RSS) during growth of marine diatom Cylindrotheca closterium isolated from the Adriatic Sea in the laboratory conditions. In the same culture samples, production of particulate and dissolved organic carbon (POC, DOC) was followed by high temperature catalytic oxidation method (HTCO). The culture growth curve obtained by microscopically counted phytoplankton cells showed an exponential growth phase that lasted 10 days, transition phase until 14 days and stationary phase until 21 days. In these time periods twofold increase of SAS and DOC was followed, while POC increased 41 times. Detail analyses of a.c. out of phase voltammetric curves recorded in original and in acidified phytoplankton culture samples indicate transformation of organic material during growth, from more anionic (negatively charged) to less anionic polymeric surface active material. In culture samples presence of non-volatile RSS were confirmed.
{"title":"Production of Surface Active Organic Material and Reduced Sulfur Species During the Growth of Marine Diatom Cylindrotheca closterium","authors":"I. Ciglenečki, J. Dautović, Ana Cvitešić, G. Pletikapić","doi":"10.5562/CCA3433","DOIUrl":"https://doi.org/10.5562/CCA3433","url":null,"abstract":"Electrochemical methods at the mercury electrode were used for monitoring production of surface active substances (SAS) and reduced sulfur species (RSS) during growth of marine diatom Cylindrotheca closterium isolated from the Adriatic Sea in the laboratory conditions. In the same culture samples, production of particulate and dissolved organic carbon (POC, DOC) was followed by high temperature catalytic oxidation method (HTCO). The culture growth curve obtained by microscopically counted phytoplankton cells showed an exponential growth phase that lasted 10 days, transition phase until 14 days and stationary phase until 21 days. In these time periods twofold increase of SAS and DOC was followed, while POC increased 41 times. Detail analyses of a.c. out of phase voltammetric curves recorded in original and in acidified phytoplankton culture samples indicate transformation of organic material during growth, from more anionic (negatively charged) to less anionic polymeric surface active material. In culture samples presence of non-volatile RSS were confirmed.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"455-461"},"PeriodicalIF":0.3,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43071507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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