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Occurrence, transportation, monitoring and treatment of emerging micro-pollutants in waste water — A review from global views
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Jia-Qian Jiang , Z. Zhou , V.K. Sharma
This paper collects data from worldwide research groups and aims to critically review and analyse the advances of knowledge development in the area of occurrence, transportation, monitoring and treatment of emerging micro-pollutants from around the globe and to recommend the research needs in this research area. This review discovers that •A waste water treatment plant is one of pathways for micro-pollutants to transfer into surface waters; •Sample preparation, matrix effects and validation methods are challenges and more advanced analytical instrumentation and procedures are critical in analysing emerging micro-pollutants; •Traditional activated sludge and/or bio-filtration processes showed less efficiency to remove emerging micro-pollutants; •Advanced oxidation processes need to be validated for the efficiency and cost effectiveness; • More researches are needed to classify the type and toxicity of by-products resulting from the reactions between advanced oxidation processes and emerging micro-pollutants. The suggested future research needs from this review are challenges but provide us opportunities to effectively monitor and eliminate emerging micro-pollutants in the environment.
Source:Microchemical Journal, Volume 110
Author(s): Jia-Qian Jiang , Z. Zhou , V.K. Sharma
This paper collects data from worldwide research groups and aims to critically review and analyse the advances of knowledge development in the area of occurrence, transportation, monitoring and treatment of emerging micro-pollutants from around the globe and to recommend the research needs in this research area. This review discovers that •A waste water treatment plant is one of pathways for micro-pollutants to transfer into surface waters; •Sample preparation, matrix effects and validation methods are challenges and more advanced analytical instrumentation and procedures are critical in analysing emerging micro-pollutants; •Traditional activated sludge and/or bio-filtration processes showed less efficiency to remove emerging micro-pollutants; •Advanced oxidation processes need to be validated for the efficiency and cost effectiveness; • More researches are needed to classify the type and toxicity of by-products resulting from the reactions between advanced oxidation processes and emerging micro-pollutants. The suggested future research needs from this review are challenges but provide us opportunities to effectively monitor and eliminate emerging micro-pollutants in the environment.
Determination of selenium compounds in food supplements using reversed-phase liquid chromatography–inductively coupled plasma mass spectrometry
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Yu-Jhe Hsieh , Shiuh-Jen Jiang
A reversed phase HPLC–ICP-MS method for the speciation of selenium compounds is described. Chromatographic separation was performed in a gradient elution mode using 2mmolL−1 sodium 1-pentanesulfonate and 5mmolL−1 citric acid in 3% methanol (pH2.70) and 5mmolL−1 NaH2PO4 and 5mmolL−1 citric acid in 3% methanol (pH2.77). The potentially interfering 38Ar40Ar+ and 40Ar40Ar+ at selenium masses of m/z 78 and 80 were reduced in intensity significantly by using 1.0mLmin−1 CH4 as a reactive cell gas in the dynamic reaction cell. Calibration curves were linear in the range 0.1–10μgL−1. The detection limits of the procedure were in the range of 0.04–0.07μgSeL−1. This method has been applied to determine various selenium compounds in NIST SRM 1567a Wheat Flour and food supplements purchased locally. The accuracy of the method has been verified by comparing the sum of the concentration of individual species obtained by the present procedure with the total concentration of the element. The selenium compounds were quantitatively extracted with a mixture of Protease XIV and mobile phase solution in a microwave field at 37°C during a period of 30min. The extraction efficiency was better than 91%. The spike recoveries were in the range of 92–104% for all determinations. The electrospray ionization-mass spectrometer has been tested to identify the unknown selenium compounds detected in the food supplements. γ-glutamyl-methyl-Se-cysteine was identified in one brand of the Selenium Tablet.
Source:Microchemical Journal, Volume 110
Author(s): Yu-Jhe Hsieh , Shiuh-Jen Jiang
A reversed phase HPLC–ICP-MS method for the speciation of selenium compounds is described. Chromatographic separation was performed in a gradient elution mode using 2mmolL−1 sodium 1-pentanesulfonate and 5mmolL−1 citric acid in 3% methanol (pH2.70) and 5mmolL−1 NaH2PO4 and 5mmolL−1 citric acid in 3% methanol (pH2.77). The potentially interfering 38Ar40Ar+ and 40Ar40Ar+ at selenium masses of m/z 78 and 80 were reduced in intensity significantly by using 1.0mLmin−1 CH4 as a reactive cell gas in the dynamic reaction cell. Calibration curves were linear in the range 0.1–10μgL−1. The detection limits of the procedure were in the range of 0.04–0.07μgSeL−1. This method has been applied to determine various selenium compounds in NIST SRM 1567a Wheat Flour and food supplements purchased locally. The accuracy of the method has been verified by comparing the sum of the concentration of individual species obtained by the present procedure with the total concentration of the element. The selenium compounds were quantitatively extracted with a mixture of Protease XIV and mobile phase solution in a microwave field at 37°C during a period of 30min. The extraction efficiency was better than 91%. The spike recoveries were in the range of 92–104% for all determinations. The electrospray ionization-mass spectrometer has been tested to identify the unknown selenium compounds detected in the food supplements. γ-glutamyl-methyl-Se-cysteine was identified in one brand of the Selenium Tablet.
Highlights
► Selenium compounds in food supplements were determined using HLPC–ICP-MS. ► Ar dimer ion interferences on Se determination were suppressed with CH4 as the DRC reaction gas. ► Selenium species were quantitatively extracted using microwave heating. ► γ-Glutamyl-methyl-Se-cysteine was identified in Selenium Tablet using ESI-MS/MS.Transport of selenium species in Caco-2 cells: Analytical approach employing the Ussing chamber technique and HPLC-ICP-MS
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Denis Pick , Christian Degen , Matthias Leiterer , Gerhard Jahreis , Jürgen W. Einax
Essential trace elements such as selenium (Se) play a crucial role in health and diseases. Investigations of the transport and absorption of different Se species in vivo and in vitro consider only one Se species in a systematic manner. Thus, transport of four Se compounds (at concentrations of 100 and 400μgL−1) namely selenite (SeO3 2−), selenate (SeO4 2−), selenomethionine (SeMet), and Se-methylselenocysteine (MeSEC) was compared using the Caco-2 cell line and the Ussing chamber system. For analytical measurements, an HPLC-ICP-DRC-MS method was developed and characterized. For the investigated Se species, limits of quantification were 0.5μgL−1 while trueness was tested using the certified reference material SELM-1. Se species were added to the apical compartment of the Ussing chamber system either separately or simultaneously. Notably, no transport for SeO3 2− from apical to basolateral side was observed. Transport efficacy after 120min was the highest (9.1%) for SeMet in single species experiments, whereas SeO4 2− transport was the highest (7.9%) associated with simultaneous adding of Se species. Furthermore, changes in rank order of the apparent permeability coefficients Papp were obtained in mixture experiments as compared to the single species approaches. Finally, experimental data demonstrate alterations in transport of SeMet, MeSEC, and SeO4 2− suggesting interactions between Se species and changes in the transport behavior.
Source:Microchemical Journal, Volume 110
Author(s): Denis Pick , Christian Degen , Matthias Leiterer , Gerhard Jahreis , Jürgen W. Einax
Essential trace elements such as selenium (Se) play a crucial role in health and diseases. Investigations of the transport and absorption of different Se species in vivo and in vitro consider only one Se species in a systematic manner. Thus, transport of four Se compounds (at concentrations of 100 and 400μgL−1) namely selenite (SeO3 2−), selenate (SeO4 2−), selenomethionine (SeMet), and Se-methylselenocysteine (MeSEC) was compared using the Caco-2 cell line and the Ussing chamber system. For analytical measurements, an HPLC-ICP-DRC-MS method was developed and characterized. For the investigated Se species, limits of quantification were 0.5μgL−1 while trueness was tested using the certified reference material SELM-1. Se species were added to the apical compartment of the Ussing chamber system either separately or simultaneously. Notably, no transport for SeO3 2− from apical to basolateral side was observed. Transport efficacy after 120min was the highest (9.1%) for SeMet in single species experiments, whereas SeO4 2− transport was the highest (7.9%) associated with simultaneous adding of Se species. Furthermore, changes in rank order of the apparent permeability coefficients Papp were obtained in mixture experiments as compared to the single species approaches. Finally, experimental data demonstrate alterations in transport of SeMet, MeSEC, and SeO4 2− suggesting interactions between Se species and changes in the transport behavior.
Highlights
► A simple and fast HPLC-ICP-DRC-MS method was developed for analysis of Se species. ► Se species were added to the Caco-2 cell model either simultaneously or separately. ► Selenite transport across Caco-2 cell monolayers is especially slow. ► Presence of other Se species influences the transport of selenate, SeMet, and MeSEC.A portable fiber-optic Raman analyzer for fast real-time screening and identifying cocrystal formation of drug-coformer via grinding process
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Hong-Liang Lin , Gang-Chun Zhang , Po-Chun Hsu , Shan-Yang Lin
A portable Raman analyzer with a fiber-optic probe was first used to rapidly screen and identify the cocrystal formation between drug and coformer. Indomethacin (IMC) and anhydrous theophylline (TP) were selected as model drugs, but saccharin (SAC) and anhydrous citric acid (CA) were chosen as model coformers. The cocrystal formation that occurred in the solid-state IMC–SAC or TP–CA system via mechanical grinding process was investigated. Differential scanning calorimetry (DSC) was also used to investigate the possible cocrystal formation. The present study indicates that this new portable fiber-opticRaman spectroscopic technique was an easy and fast “real-time” method to screen and identify the progressive cocrystal formation in solid-state IMC–SAC or TP–CA system in the process of mechanical grinding by inserting the probe directly into the ground mixtures.
Source:Microchemical Journal, Volume 110
Author(s): Hong-Liang Lin , Gang-Chun Zhang , Po-Chun Hsu , Shan-Yang Lin
A portable Raman analyzer with a fiber-optic probe was first used to rapidly screen and identify the cocrystal formation between drug and coformer. Indomethacin (IMC) and anhydrous theophylline (TP) were selected as model drugs, but saccharin (SAC) and anhydrous citric acid (CA) were chosen as model coformers. The cocrystal formation that occurred in the solid-state IMC–SAC or TP–CA system via mechanical grinding process was investigated. Differential scanning calorimetry (DSC) was also used to investigate the possible cocrystal formation. The present study indicates that this new portable fiber-opticRaman spectroscopic technique was an easy and fast “real-time” method to screen and identify the progressive cocrystal formation in solid-state IMC–SAC or TP–CA system in the process of mechanical grinding by inserting the probe directly into the ground mixtures.
Post-fire study of the Brazilian Scientific Antarctic Station: Toxic element contamination and potential mobility on the surrounding environment
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Marcelo Braga Bueno Guerra , Elias Lima Neto , Marcelo Tesser Antunes Prianti , Edenir Rodrigues Pereira-Filho , Carlos Ernesto Gonçalves Reynaud Schaefer
We evaluated the new on site soil conditions and their potential risks immediately after a fire that completely destroyed the Brazilian Antarctic Station, on February 2012. The investigated variables were the concentration of potentially toxic elements (Cd, Cr, Cu, Mn, Ni, Pb, V and Zn) in soil samples collected close to the station and inside the burnt station's ruins. Soil samples collected 4years before the fire were used as reference samples for comparative purposes. Principal Component Analysis (PCA) and μ-X-Ray Fluorescence were used as preliminary tools to provide fast and reliable qualitative information about soil pollution. Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) was chosen for the quantitative determination of the chemical elements under study. A Toxicity Characteristic Leaching Procedure was applied to access the potential mobility of the chemical elements in the environment. We found high pseudototal concentrations of Cu, Pb and Zn in soils collected within the station's ruins reaching the alarming levels of 34,000±4,000, 13,700±500 and 42,200±1,700mgkg−1, respectively. A point that deserves a close and special attention is the possible contamination of nearby lakes that supply the station with water, due to the high leachable Pb and Zn concentrations of the contaminated soil. Also, attention should be given to the possible development of melting channels carrying contaminated water to the coastal marine ecosystem. Due to its high risk of contamination, a complete clean-up procedure ought to be carried out, with barriers to avoid leaching/washing, removal of all debris and underlying soil, and careful disposal of the contaminated material, followed by remediation.
Source:Microchemical Journal, Volume 110
Author(s): Marcelo Braga Bueno Guerra , Elias Lima Neto , Marcelo Tesser Antunes Prianti , Edenir Rodrigues Pereira-Filho , Carlos Ernesto Gonçalves Reynaud Schaefer
We evaluated the new on site soil conditions and their potential risks immediately after a fire that completely destroyed the Brazilian Antarctic Station, on February 2012. The investigated variables were the concentration of potentially toxic elements (Cd, Cr, Cu, Mn, Ni, Pb, V and Zn) in soil samples collected close to the station and inside the burnt station's ruins. Soil samples collected 4years before the fire were used as reference samples for comparative purposes. Principal Component Analysis (PCA) and μ-X-Ray Fluorescence were used as preliminary tools to provide fast and reliable qualitative information about soil pollution. Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) was chosen for the quantitative determination of the chemical elements under study. A Toxicity Characteristic Leaching Procedure was applied to access the potential mobility of the chemical elements in the environment. We found high pseudototal concentrations of Cu, Pb and Zn in soils collected within the station's ruins reaching the alarming levels of 34,000±4,000, 13,700±500 and 42,200±1,700mgkg−1, respectively. A point that deserves a close and special attention is the possible contamination of nearby lakes that supply the station with water, due to the high leachable Pb and Zn concentrations of the contaminated soil. Also, attention should be given to the possible development of melting channels carrying contaminated water to the coastal marine ecosystem. Due to its high risk of contamination, a complete clean-up procedure ought to be carried out, with barriers to avoid leaching/washing, removal of all debris and underlying soil, and careful disposal of the contaminated material, followed by remediation.
Highlights
► We evaluated the post-fire condition of soil samples near the Brazilian Antarctic Station. ► Copper, Pb and Zn presented alarming levels in the soil samples collected. ► μ-X-Ray Fluorescence in combination with chemometrics provides fast and reliable information. ► A complete clean-up procedure ought to be carried out to avoid leaching/washing.Mercury species determination by task specific ionic liquid-based ultrasound-assisted dispersive liquid–liquid microextraction combined with cold vapour generation atomic absorption spectrometry
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Ewa Stanisz , Justyna Werner , Henryk Matusiewicz
Task specific ionic liquid-based ultrasound-assisted dispersive liquid–liquid microextraction (TSIL USA DLLME) combined with cold vapour atomic absorption spectrometry (CV AAS) for determination of mercury species in water and biological samples was developed. The proposed procedure was free of volatile organic solvents, and there was no need to use any dispersive solvents and complexing agents, in contrast to standard DLLME. Analytical signals were obtained without the back-extraction of the mercury species from the TSIL phase into an aqueous phase prior to their determination by CV AAS. The reducing agent Sn2+ could reduce Hg2+ and CH3Hg+ for determination of total mercury. Some essential parameters of the microextraction and cold vapour generation, such as the pH of sample solution, volume of the ionic liquid, ultrasonication time, cooling time, centrifugation time, matrix interferences and salt effect have been studied. Under optimal conditions, high extraction efficiency was achieved for the extraction of 1.0ngmL−1 of Hg2+ and 5ngmL−1 CH3Hg+ in 10.0mL of water solution employing 30μL of methyltrioctylammonium thiosalicylate as the extraction solvent. The enrichment factor for the method was 310 for Hg2+ and 200 for CH3Hg+. The detection limits were 0.03ngmL−1 for Hg2+ and 0.4ngmL−1 for CH3Hg+ respectively. The accuracy of the proposed method was evaluated by analysis of the Certified Reference Materials (NRCC DOLT-2, NIST 1643e). The method was applied to analysis of the tap, river, lake and sea water samples. The recoveries for reference materials and spiked samples were in the range of 95-103%.
Source:Microchemical Journal, Volume 110
Author(s): Ewa Stanisz , Justyna Werner , Henryk Matusiewicz
Task specific ionic liquid-based ultrasound-assisted dispersive liquid–liquid microextraction (TSIL USA DLLME) combined with cold vapour atomic absorption spectrometry (CV AAS) for determination of mercury species in water and biological samples was developed. The proposed procedure was free of volatile organic solvents, and there was no need to use any dispersive solvents and complexing agents, in contrast to standard DLLME. Analytical signals were obtained without the back-extraction of the mercury species from the TSIL phase into an aqueous phase prior to their determination by CV AAS. The reducing agent Sn2+ could reduce Hg2+ and CH3Hg+ for determination of total mercury. Some essential parameters of the microextraction and cold vapour generation, such as the pH of sample solution, volume of the ionic liquid, ultrasonication time, cooling time, centrifugation time, matrix interferences and salt effect have been studied. Under optimal conditions, high extraction efficiency was achieved for the extraction of 1.0ngmL−1 of Hg2+ and 5ngmL−1 CH3Hg+ in 10.0mL of water solution employing 30μL of methyltrioctylammonium thiosalicylate as the extraction solvent. The enrichment factor for the method was 310 for Hg2+ and 200 for CH3Hg+. The detection limits were 0.03ngmL−1 for Hg2+ and 0.4ngmL−1 for CH3Hg+ respectively. The accuracy of the proposed method was evaluated by analysis of the Certified Reference Materials (NRCC DOLT-2, NIST 1643e). The method was applied to analysis of the tap, river, lake and sea water samples. The recoveries for reference materials and spiked samples were in the range of 95-103%.
Highlights
► The preconcentration of mercury species with TSIL USA DLLME is optimized. ► The determination by CV AAS in organic phase without back-extraction is proposed. ► The method requires low volume of sample and reagents. ► A low limit of detection, good precision and high enhancement factor were obtained. ► An application to mercury species determination in complex matrices was shown.Study of the effect of plasticizer on the structure and surface characteristics of ethylcellulose free films with FT-IR spectroscopy
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Diána Hegyesi , Tamás Sovány , Ottó Berkesi , Klára Pintye-Hódi , Géza Regdon Jr.
The investigation of free films is an essential part of the preformulation studies, because it is necessary to know, weather the given formulation is suitable to coat the corpus or not. As preformulation, the relationships between surface properties, and the structure of ethylcellulose free films containing different amount of plasticizer were studied. The structure analysis, and the incorporation of the plasticizer was performed with the use of FT-IR analysis. The results showed that the films are suitable to produce diffusion coatings.
Source:Microchemical Journal, Volume 110
Author(s): Diána Hegyesi , Tamás Sovány , Ottó Berkesi , Klára Pintye-Hódi , Géza Regdon Jr.
The investigation of free films is an essential part of the preformulation studies, because it is necessary to know, weather the given formulation is suitable to coat the corpus or not. As preformulation, the relationships between surface properties, and the structure of ethylcellulose free films containing different amount of plasticizer were studied. The structure analysis, and the incorporation of the plasticizer was performed with the use of FT-IR analysis. The results showed that the films are suitable to produce diffusion coatings.
Sensitive voltammetric responses and mechanistic insights into the determination of residue levels of endosulfan in fresh foodstuffs and raw natural waters
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Francisco W.P. Ribeiro , Thiago M.B.F. Oliveira , Francisco L.F. da Silva , Glaydson L.F. Mendonça , Paula Homem-de-Mello , Helena Becker , Pedro de Lima-Neto , Adriana N. Correia , Valder Nogueira Freire
This paper describes the electroanalytical study of the organochlorine pesticide endosulfan (EDS) using square-wave voltammetry. The electrochemical behaviour showed a quasi-reversible process on a hanging mercury drop electrode (HMDE) in acid medium attributed to reduction of the carbon–chlorine bond. The constant of change transfer obtained for this process was 354s−1. The redox mechanism was confirmed by quantum-chemical (Density Functional Theory, DFT) studies. The optimised experimental and voltammetric parameters were 0.04molL−1 Britton–Robinson buffer (pH4.0), the pulse potential frequency of 200s−1, the amplitude of the pulse of 20mV, and the height of the potential step of 4mV. Analytical parameters such as linearity range, equation of the analytical curves, correlation coefficients, detection and quantification limits, recovery values, precision, and accuracy were obtained. The procedure was applied to the analysis of pesticide in complex samples: sugar cane, tomato, and raw natural waters. The recovery values demonstrated that the proposed methodology is suitable for determining EDS in such samples. The results indicated that the proposed procedure is stable and sensitive, with good reproducibility, and no complex procedure was necessary for sample preparation. The development of this electroanalytical procedure is therefore appropriate, as it provides adequate sensitivity and reliable methodology.
Source:Microchemical Journal, Volume 110
Author(s): Francisco W.P. Ribeiro , Thiago M.B.F. Oliveira , Francisco L.F. da Silva , Glaydson L.F. Mendonça , Paula Homem-de-Mello , Helena Becker , Pedro de Lima-Neto , Adriana N. Correia , Valder Nogueira Freire
This paper describes the electroanalytical study of the organochlorine pesticide endosulfan (EDS) using square-wave voltammetry. The electrochemical behaviour showed a quasi-reversible process on a hanging mercury drop electrode (HMDE) in acid medium attributed to reduction of the carbon–chlorine bond. The constant of change transfer obtained for this process was 354s−1. The redox mechanism was confirmed by quantum-chemical (Density Functional Theory, DFT) studies. The optimised experimental and voltammetric parameters were 0.04molL−1 Britton–Robinson buffer (pH4.0), the pulse potential frequency of 200s−1, the amplitude of the pulse of 20mV, and the height of the potential step of 4mV. Analytical parameters such as linearity range, equation of the analytical curves, correlation coefficients, detection and quantification limits, recovery values, precision, and accuracy were obtained. The procedure was applied to the analysis of pesticide in complex samples: sugar cane, tomato, and raw natural waters. The recovery values demonstrated that the proposed methodology is suitable for determining EDS in such samples. The results indicated that the proposed procedure is stable and sensitive, with good reproducibility, and no complex procedure was necessary for sample preparation. The development of this electroanalytical procedure is therefore appropriate, as it provides adequate sensitivity and reliable methodology.
Highlights
► Endosulfan is a broad-spectrum insecticide and acaricide applied in different areas. ► HMDE and SWV were used in the electroanalytical methodology. ► EDS determination in sugar cane, tomato and raw natural water samples ► Quantum-chemistry in a proposition of pathway for EDS electroreduction.Determination of critical micelle concentration of dendritic surfactant synthesized via a selective ring-opening addition reaction
11 June 2013,
10:59:19
Publication date: September
2013
Source:Microchemical Journal, Volume 110
Author(s): Chih-Hsiung Hsu , Shi-Min Shau , Ru-Jong Jeng , Hsin-Cheng Chiu , Shenghong A. Dai , Eric D. Conte , Shing-Yi Suen
An azetidine-2,4-dione was applied to synthesize dendrons with four carbons in the end ([G-0.5]-C4 and [G-1]-C4) via a selective ring-opening addition reaction, which was subsequently extended to obtain a dendritic surfactant ([G-1]-C4 surfactant) by acidification. The dendrons were characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), elemental analyzer (EA), and fast atom bombardment mass spectrometry (FAB MS). The dendritic surfactant, with a cationic head and branched hydrophobic C4 tails, was dissolved in 2wt.% dimethyl sulfoxide (DMSO) aqueous solution for the determination of critical micelle concentration (CMC) by fluorescence and electrical conductivity measurements. The resulted CMC values were very close within measurements, ca. 0.013–0.05mM. Transmission electron microscopy (TEM) and zeta potential measurement also provided an evidence of micelle formation and shape. Moreover, anionic dyes were adsorbed onto the micelles successfully to confirm the positive charge of [G-1]-C4 surfactant.
Source:Microchemical Journal, Volume 110
Author(s): Chih-Hsiung Hsu , Shi-Min Shau , Ru-Jong Jeng , Hsin-Cheng Chiu , Shenghong A. Dai , Eric D. Conte , Shing-Yi Suen
An azetidine-2,4-dione was applied to synthesize dendrons with four carbons in the end ([G-0.5]-C4 and [G-1]-C4) via a selective ring-opening addition reaction, which was subsequently extended to obtain a dendritic surfactant ([G-1]-C4 surfactant) by acidification. The dendrons were characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), elemental analyzer (EA), and fast atom bombardment mass spectrometry (FAB MS). The dendritic surfactant, with a cationic head and branched hydrophobic C4 tails, was dissolved in 2wt.% dimethyl sulfoxide (DMSO) aqueous solution for the determination of critical micelle concentration (CMC) by fluorescence and electrical conductivity measurements. The resulted CMC values were very close within measurements, ca. 0.013–0.05mM. Transmission electron microscopy (TEM) and zeta potential measurement also provided an evidence of micelle formation and shape. Moreover, anionic dyes were adsorbed onto the micelles successfully to confirm the positive charge of [G-1]-C4 surfactant.
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