Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4808
Vytautas Kavaliauskas, V. Olšauskaitė, A. Padarauskas
In this study, eight hydrophobic supramolecular (SUPRA) solvents composed of tetrabutylammonium chloride and tetradecyltrimethylammonium bromide as amphiphiles and four perfluorinated compounds (hexafluoroisopropanol, trifluoroacetic acid, pentafluoropropionic acid and heptafluorobutyric acid) as coacervation-inducing agents were developed. The SUPRA phase volumes were determined as a function of individual concentrations of the system components. The extraction properties of the SUPRA solvents for the extraction of phthalates from the model aqueous solutions were investigated and their applicability as sample diluents for the reversed-phase HPLC separations of phthalates was tested. Finally, the solvent consisting of tetradecyltrimethylammonium bromide and hexafluoroisopropanol was applied for dispersive liquid-liquid microextraction of phthalates from wastewater samples prior to HPLC analysis. Under optimised extraction conditions, the enrichment factors were around 75. The calibration curves were linear (R2 ≥ 0.9965) for the concentration level between 1.00 and 50.0 μg/L and the detection limits were in the range 0.3–0.6 μg/L. The recoveries of the phthalates of the developed method for the spiked wastewater samples were 93.1–104.4%, with the relative standard deviation values less than 7.4%.
{"title":"Supramolecular solvents based on quaternary ammonium salts and perfluorinated compounds for dispersive liquid-liquid microextraction of phthalates","authors":"Vytautas Kavaliauskas, V. Olšauskaitė, A. Padarauskas","doi":"10.6001/chemija.v33i4.4808","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4808","url":null,"abstract":"In this study, eight hydrophobic supramolecular (SUPRA) solvents composed of tetrabutylammonium chloride and tetradecyltrimethylammonium bromide as amphiphiles and four perfluorinated compounds (hexafluoroisopropanol, trifluoroacetic acid, pentafluoropropionic acid and heptafluorobutyric acid) as coacervation-inducing agents were developed. The SUPRA phase volumes were determined as a function of individual concentrations of the system components. The extraction properties of the SUPRA solvents for the extraction of phthalates from the model aqueous solutions were investigated and their applicability as sample diluents for the reversed-phase HPLC separations of phthalates was tested. Finally, the solvent consisting of tetradecyltrimethylammonium bromide and hexafluoroisopropanol was applied for dispersive liquid-liquid microextraction of phthalates from wastewater samples prior to HPLC analysis. Under optimised extraction conditions, the enrichment factors were around 75. The calibration curves were linear (R2 ≥ 0.9965) for the concentration level between 1.00 and 50.0 μg/L and the detection limits were in the range 0.3–0.6 μg/L. The recoveries of the phthalates of the developed method for the spiked wastewater samples were 93.1–104.4%, with the relative standard deviation values less than 7.4%.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41547279","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4806
A. Žalga, Austėja Diktanaitė, Giedrė Gaidamavičienė
Aqueous tartaric acid-assisted sol–gel preparation technique was successfully applied to synthesise lithium aluminium molybdate with the initial composition of LiAl(MoO4)2. From the results of the thermal analysis and Xray diffraction measurement, the effect of tartaric acid as a ligand on the formation of homogeneous gel precursor was discussed. Besides, X-ray diffraction also revealed the crystallisation of the final LiAlMo2O8 ceramic below the temperature of 400°C. It was found that the initial composition of obtained ceramic significantly affected the formation of the impurity phase defined as AlMo2O12. The Rietveld refinement of the crystalline samples showed the tendency of crystallites growing with the increase of heat-treatment temperature. Similar trends of particle growing were also observed in the images of scanning electron microscopy (SEM) for the corresponding samples heat-treated at different temperatures. Finally, the Fourier-transform infrared spectroscopy (FT-IR) revealed the effect of both the surface morphology and the crystallite size on the intensity of characteristic vibration of the corresponding chemical bonds.
{"title":"Aqueous sol–gel synthesis, thermoanalytical, structural and vibrational studies of lithium aluminium molybdate (LiAlMo2O8)","authors":"A. Žalga, Austėja Diktanaitė, Giedrė Gaidamavičienė","doi":"10.6001/chemija.v33i4.4806","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4806","url":null,"abstract":"Aqueous tartaric acid-assisted sol–gel preparation technique was successfully applied to synthesise lithium aluminium molybdate with the initial composition of LiAl(MoO4)2. From the results of the thermal analysis and Xray diffraction measurement, the effect of tartaric acid as a ligand on the formation of homogeneous gel precursor was discussed. Besides, X-ray diffraction also revealed the crystallisation of the final LiAlMo2O8 ceramic below the temperature of 400°C. It was found that the initial composition of obtained ceramic significantly affected the formation of the impurity phase defined as AlMo2O12. The Rietveld refinement of the crystalline samples showed the tendency of crystallites growing with the increase of heat-treatment temperature. Similar trends of particle growing were also observed in the images of scanning electron microscopy (SEM) for the corresponding samples heat-treated at different temperatures. Finally, the Fourier-transform infrared spectroscopy (FT-IR) revealed the effect of both the surface morphology and the crystallite size on the intensity of characteristic vibration of the corresponding chemical bonds.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41829227","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4805
Artur Harnik, M. Misevicius
In this research pristine, Bi-doped and Eu-doped LiAlGeO4 were prepared using a solid-state synthesis method. All samples were analysed by X-ray powder diffraction (XRD) and luminescence measurements. The highest Eu3+ concentration yielding monophasic samples in LiAl1-xGeO4: Eux was x = 0.08, while higher doping concentrations resulted in the formation of additional phases. The luminescence measurements revealed that the highest emission intensity was observed in the 16% Eu sample. Furthermore, the same sample demonstrated the highest quantum yield, while the longest luminescence decay was observed in the LiAlGeO4:Eu 1% sample. The temperature-dependent luminescence measurements revealed that phosphor lost half of its efficiency at 323 K.
{"title":"Solid-state synthesis and luminescence study of Bi or Eu-doped LiAlGeO4","authors":"Artur Harnik, M. Misevicius","doi":"10.6001/chemija.v33i4.4805","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4805","url":null,"abstract":"In this research pristine, Bi-doped and Eu-doped LiAlGeO4 were prepared using a solid-state synthesis method. All samples were analysed by X-ray powder diffraction (XRD) and luminescence measurements. The highest Eu3+ concentration yielding monophasic samples in LiAl1-xGeO4: Eux was x = 0.08, while higher doping concentrations resulted in the formation of additional phases. The luminescence measurements revealed that the highest emission intensity was observed in the 16% Eu sample. Furthermore, the same sample demonstrated the highest quantum yield, while the longest luminescence decay was observed in the LiAlGeO4:Eu 1% sample. The temperature-dependent luminescence measurements revealed that phosphor lost half of its efficiency at 323 K.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43012371","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4811
Ieva Čalkaitė, Algimanta Kundrotaitė, V. Tilvikienė, K. Barčauskaitė
Industrial hemp (Cannabis sativa L.) is a very beneficial plant because it is characterised as easy adaptable and advantageous raw material for many products which are used in daily life. Hempseeds are investigated most of all, but there is no a lot of information about other parts of this plant (stem, leaves and inflorescences). In this study, polyphenolic compounds, flavonoids and the radical scavenging activity of Cannabis sativa L. were investigated. The influence of two different sowing rates (15 and 80 plants per square meter) and two solvents on the recovery of biologically active compounds was determined. Spectrophotometric tests were used for the identification of phenolic compounds and flavonoids content and their radical scavenging activity. It was found that industrial hemp which grew in the sparse area accumulated more biologically active compounds and was a better radical scavenger than the other one, which grew under denser conditions. Moreover, it was determined that polyphenolic compounds dissolved better in methanol and thus showed better radical scavenging properties while flavonoids dissolved better in ethanol.
{"title":"The effect of sowing rate on the bioaccumulation of biologically active compounds and their radical scavenging activity in Cannabis sativa L","authors":"Ieva Čalkaitė, Algimanta Kundrotaitė, V. Tilvikienė, K. Barčauskaitė","doi":"10.6001/chemija.v33i4.4811","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4811","url":null,"abstract":"Industrial hemp (Cannabis sativa L.) is a very beneficial plant because it is characterised as easy adaptable and advantageous raw material for many products which are used in daily life. Hempseeds are investigated most of all, but there is no a lot of information about other parts of this plant (stem, leaves and inflorescences). In this study, polyphenolic compounds, flavonoids and the radical scavenging activity of Cannabis sativa L. were investigated. The influence of two different sowing rates (15 and 80 plants per square meter) and two solvents on the recovery of biologically active compounds was determined. Spectrophotometric tests were used for the identification of phenolic compounds and flavonoids content and their radical scavenging activity. It was found that industrial hemp which grew in the sparse area accumulated more biologically active compounds and was a better radical scavenger than the other one, which grew under denser conditions. Moreover, it was determined that polyphenolic compounds dissolved better in methanol and thus showed better radical scavenging properties while flavonoids dissolved better in ethanol.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44986184","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4810
V. Vickackaite, Sandra Petrokaitė, Vilius Poškus
Hypericum Perforatum L., commonly known as St. John’s wort, is one of the best-known medicinal herbs. St. John’s wort infused oils are mostly used externally, but can be taken orally for stomach ulcers, are used as a food supplement. Therefore, it is important to develop methods that allow a rapid and reliable determination of β-caryophyllene, which is one of the main active components of St. John’s wort. In this work, two gas chromatographic techniques, static headspace gas chromatography (SHS-GC) and solid phase microextraction, combined with gas chromatography-mass spectrometry (SPME-GC-MS), were examined for the determination of β-caryophyllene in St. John’s wort infused oils. A comparison of these two techniques revealed that SPME-GC-MS can be successfully applied for the analysis. The other method, SHS-GC, is simple and fast, but because of its high detection limit, it can only be applied to oil samples with β-caryophyllene concentration higher than 0.1 mg/g.
{"title":"Gas chromatography for β-caryophyllene determination in St. John’s wort infused oil","authors":"V. Vickackaite, Sandra Petrokaitė, Vilius Poškus","doi":"10.6001/chemija.v33i4.4810","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4810","url":null,"abstract":"Hypericum Perforatum L., commonly known as St. John’s wort, is one of the best-known medicinal herbs. St. John’s wort infused oils are mostly used externally, but can be taken orally for stomach ulcers, are used as a food supplement. Therefore, it is important to develop methods that allow a rapid and reliable determination of β-caryophyllene, which is one of the main active components of St. John’s wort. In this work, two gas chromatographic techniques, static headspace gas chromatography (SHS-GC) and solid phase microextraction, combined with gas chromatography-mass spectrometry (SPME-GC-MS), were examined for the determination of β-caryophyllene in St. John’s wort infused oils. A comparison of these two techniques revealed that SPME-GC-MS can be successfully applied for the analysis. The other method, SHS-GC, is simple and fast, but because of its high detection limit, it can only be applied to oil samples with β-caryophyllene concentration higher than 0.1 mg/g.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46289204","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4830
R. Pauliukaitė, J. Juodkazytė, A. Malinauskas
Lithuanian writer and poet Justinas Marcinkevičius said: ‘If there is a vocation at all, then the noblest vocation is work.’ These words well characterise Prof. Rimantas Ramanauskas, whose diligent work and dedication to science had a great impact on electrochemical research in Lithuania and the Center for Physical Sciences and Technology (FTMC).
{"title":"Resistivity to corrosion via corrosionphilia. Professor Rimantas Ramanauskas turned 70","authors":"R. Pauliukaitė, J. Juodkazytė, A. Malinauskas","doi":"10.6001/chemija.v33i4.4830","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4830","url":null,"abstract":"Lithuanian writer and poet Justinas Marcinkevičius said: ‘If there is a vocation at all, then the noblest vocation is work.’ These words well characterise Prof. Rimantas Ramanauskas, whose diligent work and dedication to science had a great impact on electrochemical research in Lithuania and the Center for Physical Sciences and Technology (FTMC).","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46760358","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4804
Emilija Katinaitė, Vytautas Žutautas, Aneta Bytautaitė, R. Pauliukaitė
Determination of pesticides is important for human health. Sensors are one of the best solutions because they do not require a long sample preparation and can be used not only in a laboratory. Electrochemical sensors can be easily minimised and employed for the detection of pesticides in liquid samples such as ground or wastewater. Conducting polymers have a few roles in electrochemical sensors, therefore, they can be good candidates for sensor development. Electrochemically co-polymerised folic acid and riboflavin as well as folic acid and L-lysine were employed for the detection of atrazine using square wave voltammetry. The co-polymer composition was optimised and characterised electrochemically and spectroscopically. The optimal composition of polyfolic acid and poly-L-lysine co-polymer electrosynthesised from the monomer ratio 1:10 was the best in terms of stability and sensitivity to atrazine. The best method was the square wave voltammetry showing the best sensitivity to atrazine 198 ± 1 μA/μM cm2, and the limit of detection was 14.8 nM. However, the sensitivity in tap water was significantly lower but still suitable for atrazine detection by the spike method.
{"title":"A novel strategy to develop electrochemical atrazine sensor","authors":"Emilija Katinaitė, Vytautas Žutautas, Aneta Bytautaitė, R. Pauliukaitė","doi":"10.6001/chemija.v33i4.4804","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4804","url":null,"abstract":"Determination of pesticides is important for human health. Sensors are one of the best solutions because they do not require a long sample preparation and can be used not only in a laboratory. Electrochemical sensors can be easily minimised and employed for the detection of pesticides in liquid samples such as ground or wastewater. Conducting polymers have a few roles in electrochemical sensors, therefore, they can be good candidates for sensor development. Electrochemically co-polymerised folic acid and riboflavin as well as folic acid and L-lysine were employed for the detection of atrazine using square wave voltammetry. The co-polymer composition was optimised and characterised electrochemically and spectroscopically. The optimal composition of polyfolic acid and poly-L-lysine co-polymer electrosynthesised from the monomer ratio 1:10 was the best in terms of stability and sensitivity to atrazine. The best method was the square wave voltammetry showing the best sensitivity to atrazine 198 ± 1 μA/μM cm2, and the limit of detection was 14.8 nM. However, the sensitivity in tap water was significantly lower but still suitable for atrazine detection by the spike method.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41938873","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}
Pub Date : 2022-12-09DOI: 10.6001/chemija.v33i4.4807
Monika Baublytė, J. Kupčiūnaitė, Milda Liubinienė, A. Beganskiene
Water immersion is a common practice for treating paper media. However, this treatment could irreversibly damage paper and the information written on it – such procedures are advised if the documents do not contain water-resistant components such as inks or paints and the form is mechanically stable. Thus, polymeric materials are an attractive alternative to water immersion cleaning. Various polymers are used to produce hydrogels, but there is not much information on cleaning effects before and after aging. Due to their highly rigid properties, Kelcogel, TopVision Agarose and PhytagelTM hydrogels could be applied to clean fragile paper media instead of water immersion. The hydrogel could safely clean without any residue or change of paper properties. Selected polymers were analysed for composition, water discharge and acidity according to the corresponding requirements for restoration processes: to establish changes in chemical and physical paper properties after hydrogel cleaning, filter paper samples were analysed with SEM, TGA, FTIR and pH-meter and compared to the benchmarks of filter paper cleaned with distilled water.
{"title":"Hydrogels – a desirable alternative to water paper restoring procedures: impacting paper properties","authors":"Monika Baublytė, J. Kupčiūnaitė, Milda Liubinienė, A. Beganskiene","doi":"10.6001/chemija.v33i4.4807","DOIUrl":"https://doi.org/10.6001/chemija.v33i4.4807","url":null,"abstract":"Water immersion is a common practice for treating paper media. However, this treatment could irreversibly damage paper and the information written on it – such procedures are advised if the documents do not contain water-resistant components such as inks or paints and the form is mechanically stable. Thus, polymeric materials are an attractive alternative to water immersion cleaning. Various polymers are used to produce hydrogels, but there is not much information on cleaning effects before and after aging. Due to their highly rigid properties, Kelcogel, TopVision Agarose and PhytagelTM hydrogels could be applied to clean fragile paper media instead of water immersion. The hydrogel could safely clean without any residue or change of paper properties. Selected polymers were analysed for composition, water discharge and acidity according to the corresponding requirements for restoration processes: to establish changes in chemical and physical paper properties after hydrogel cleaning, filter paper samples were analysed with SEM, TGA, FTIR and pH-meter and compared to the benchmarks of filter paper cleaned with distilled water.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42088998","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}
Pub Date : 2022-08-07DOI: 10.6001/chemija.v33i3.4749
U. Griškevičienė, M. Marksa, A. Ževžikovienė, A. Ževžikovas, L. Ivanauskas
Amino acids are one of the main particles in a living organism. They perform many different functions, such as structural, receptor, energetic and enzymatic functions [1]. The aim of the investigation was to identify and evaluate the qualitative composition of free amino acids in samples of Cirsium vulgare material using gas chromatography–mass spectrometry (GC-MS). Our objectives were to apply the gas chromatography– mass spectrometry (GC-MS) method for free amino acids from Cirsium vulgare raw materials grown in Lithuania and determine the qualitative composition of free amino acids from extracts of Cirsium vulgare raw materials: roots, leaves, flowers and seeds. MTBSTFA (N-methyl-N-(tertbutyldimethylsilyl) trifluoroacetamide) was selected for derivatisation in free amino acid analysis. Applying gas chromatography–mass spectrometry with compound derivatisation and based on the mass spectral database free amino acids were identified in bull thistle raw material: L-alanine, glycine, L-valine, L-leucine, L-isoleucine, L-proline, L-serine, L-threonine, L-phenylalanine, L-lysine, L-tyrosine, L-aspartic acid and L-glutamic acid. Studies have shown that the qualitative composition of free amino acids depends on the plant vegetation phase and plant parts.
{"title":"Evaluation of free amino acids in Cirsium vulgare (Bull thistle) plant materials using gas chromatography–mass spectrometry","authors":"U. Griškevičienė, M. Marksa, A. Ževžikovienė, A. Ževžikovas, L. Ivanauskas","doi":"10.6001/chemija.v33i3.4749","DOIUrl":"https://doi.org/10.6001/chemija.v33i3.4749","url":null,"abstract":"Amino acids are one of the main particles in a living organism. They perform many different functions, such as structural, receptor, energetic and enzymatic functions [1]. The aim of the investigation was to identify and evaluate the qualitative composition of free amino acids in samples of Cirsium vulgare material using gas chromatography–mass spectrometry (GC-MS). Our objectives were to apply the gas chromatography– mass spectrometry (GC-MS) method for free amino acids from Cirsium vulgare raw materials grown in Lithuania and determine the qualitative composition of free amino acids from extracts of Cirsium vulgare raw materials: roots, leaves, flowers and seeds. MTBSTFA (N-methyl-N-(tertbutyldimethylsilyl) trifluoroacetamide) was selected for derivatisation in free amino acid analysis. Applying gas chromatography–mass spectrometry with compound derivatisation and based on the mass spectral database free amino acids were identified in bull thistle raw material: L-alanine, glycine, L-valine, L-leucine, L-isoleucine, L-proline, L-serine, L-threonine, L-phenylalanine, L-lysine, L-tyrosine, L-aspartic acid and L-glutamic acid. Studies have shown that the qualitative composition of free amino acids depends on the plant vegetation phase and plant parts.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41373319","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}
Pub Date : 2022-08-07DOI: 10.6001/chemija.v33i3.4752
M. Dailidė, S. Tumkevičius
ynthesis of 2,4-diamino-6-(arylaminomethyl)thieno[2,3-d]pyrimidines as potential lipophilic antifolates has been developed. The synthetic strategy is based on a sequential transformation of readily available ethyl 2-amino-4-chlorothieno[2,3-d]pyrimidine-6-caboxylate to 2,4-diaminothieno[2,3-d]pyrimidine-6-carbaldehyde, which in the reaction with the corresponding anilines in titanium isopropoxide in the presence of sodium borohydride furnished the title compounds.
{"title":"Synthesis of novel 2,4-diamino-6-(arylaminomethyl)thieno[2,3-d]pyrimidines as potential antifolates","authors":"M. Dailidė, S. Tumkevičius","doi":"10.6001/chemija.v33i3.4752","DOIUrl":"https://doi.org/10.6001/chemija.v33i3.4752","url":null,"abstract":"ynthesis of 2,4-diamino-6-(arylaminomethyl)thieno[2,3-d]pyrimidines as potential lipophilic antifolates has been developed. The synthetic strategy is based on a sequential transformation of readily available ethyl 2-amino-4-chlorothieno[2,3-d]pyrimidine-6-caboxylate to 2,4-diaminothieno[2,3-d]pyrimidine-6-carbaldehyde, which in the reaction with the corresponding anilines in titanium isopropoxide in the presence of sodium borohydride furnished the title compounds.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41622731","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：