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Recent applications in derivative ultraviolet/visible absorption spectrophotometry: 2009–2011 A review
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
C. Bosch Ojeda, F. Sanchez Rojas
Derivative spectrophotometry (DS) has been introduced for the resolution of overlapping peaks. DS method has been widely used to enhance the signal and resolve the overlapped peak-signals due to its advantages in differentiating closely adjacent peaks, and identifying weak peaks obscured by sharp peaks. In this work, the analytical applications of derivative UV/VIS region absorption spectrophotometry produced in the last 3years (since 2009) are reviewed.
Source:Microchemical Journal, Volume 106
C. Bosch Ojeda, F. Sanchez Rojas
Derivative spectrophotometry (DS) has been introduced for the resolution of overlapping peaks. DS method has been widely used to enhance the signal and resolve the overlapped peak-signals due to its advantages in differentiating closely adjacent peaks, and identifying weak peaks obscured by sharp peaks. In this work, the analytical applications of derivative UV/VIS region absorption spectrophotometry produced in the last 3years (since 2009) are reviewed.
Highlights
► DS opens up possibilities for increasing selectivity and sensitivity. ► DS is used to determine elements with high accuracy without any previous step. ► DS is very useful when overlap or interference exists. ► DS offers a powerful tool for qualitative and quantitative analyses of mixtures.Easy to use spectrophotometric method for determination of aromatic diamines in biodiesel samples
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Luciano N. Batista, Viviane F. Silva, Mauricio G. Fonseca, Erica C.G. Pissurno, Romeu J. Daroda, Valnei S. Cunha, Claudete N. Kunigami, Luiz Claudio de Santa Maria
Biodiesel is the main partial substitute for petrodiesel. Some biodiesels have low oxidative stability. To solve or minimize this problem, some compounds have been added to biodiesel as antioxidants. One of the most efficient classes of compounds used for this is aromatic diamines because of their high antioxidant capacity at low concentration. Aromatic diamines can be used as artificial markers. It is sometimes necessary to determine the concentration of antioxidants in biodiesel after long storage times or to control quality. An easy to use spectrophotometric methodology was employed in this work to determine the concentration of aromatic diamines (0 to 500ppm). Five calibration curves were constructed using 3 absorption frequencies from the infrared spectra of the samples. The standard deviation, correlation coefficient, linearity range, limit of detection and limit of quantification were determined. The better results from the easy to use method (814cm−1) show a linear range of 0–100ppm with a strong correlation (R2=0.9966) and a limit of quantification of 21.6ppm.
Source:Microchemical Journal, Volume 106
Luciano N. Batista, Viviane F. Silva, Mauricio G. Fonseca, Erica C.G. Pissurno, Romeu J. Daroda, Valnei S. Cunha, Claudete N. Kunigami, Luiz Claudio de Santa Maria
Biodiesel is the main partial substitute for petrodiesel. Some biodiesels have low oxidative stability. To solve or minimize this problem, some compounds have been added to biodiesel as antioxidants. One of the most efficient classes of compounds used for this is aromatic diamines because of their high antioxidant capacity at low concentration. Aromatic diamines can be used as artificial markers. It is sometimes necessary to determine the concentration of antioxidants in biodiesel after long storage times or to control quality. An easy to use spectrophotometric methodology was employed in this work to determine the concentration of aromatic diamines (0 to 500ppm). Five calibration curves were constructed using 3 absorption frequencies from the infrared spectra of the samples. The standard deviation, correlation coefficient, linearity range, limit of detection and limit of quantification were determined. The better results from the easy to use method (814cm−1) show a linear range of 0–100ppm with a strong correlation (R2=0.9966) and a limit of quantification of 21.6ppm.
Highlights
► Evaluation of easy to use spectrophotometric method ► No complex math was used. ► Uncommon antioxidant was used but with high efficiency. ► Metrological limits were evaluated, with excellent results.A single-phase spectrophotometric procedure for in situ analysis of free glycerol in biodiesel
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Mauricio S. Ribeiro, Fábio R.P. Rocha
Biodiesel can be obtained from renewable sources by catalytic transesterification of vegetable oils or animal fats, yielding alkyl esters of fatty acids and glycerol as a by-product. Glycerol needs to be removed before commercialization of the biofuel because high concentrations can damage motors and produce highly toxic gases during combustion. The aim of this work was to develop a procedure for in situ analysis of free glycerol in biodiesel samples exploiting a single-phase system. The time-consuming analyte extraction and phase separation, usually employed in previously proposed procedures, were both avoided. Anhydrous ethanol was used to simultaneously dissolve the biodiesel and the chromogenic reagents and the final solution should contain at least 85% ethanol to ensure the formation of a single phase before the spectrophotometric measurements. A linear response was observed from 20.0 to 400.0mgkg−1 glycerol, described by the equation: A=0.0018C+0.0204, r=0.999, in which C is the concentration of glycerol in mgkg−1. The detection limit was estimated at 2.0mgkg−1 (99.7% confidence level) and the coefficient of variation was 2.1% (n=10). The proposed procedure was successfully applied to biodiesel samples from different fat sources and the results agreed with the reference procedure at the 95% confidence level.
Source:Microchemical Journal, Volume 106
Mauricio S. Ribeiro, Fábio R.P. Rocha
Biodiesel can be obtained from renewable sources by catalytic transesterification of vegetable oils or animal fats, yielding alkyl esters of fatty acids and glycerol as a by-product. Glycerol needs to be removed before commercialization of the biofuel because high concentrations can damage motors and produce highly toxic gases during combustion. The aim of this work was to develop a procedure for in situ analysis of free glycerol in biodiesel samples exploiting a single-phase system. The time-consuming analyte extraction and phase separation, usually employed in previously proposed procedures, were both avoided. Anhydrous ethanol was used to simultaneously dissolve the biodiesel and the chromogenic reagents and the final solution should contain at least 85% ethanol to ensure the formation of a single phase before the spectrophotometric measurements. A linear response was observed from 20.0 to 400.0mgkg−1 glycerol, described by the equation: A=0.0018C+0.0204, r=0.999, in which C is the concentration of glycerol in mgkg−1. The detection limit was estimated at 2.0mgkg−1 (99.7% confidence level) and the coefficient of variation was 2.1% (n=10). The proposed procedure was successfully applied to biodiesel samples from different fat sources and the results agreed with the reference procedure at the 95% confidence level.
Highlights
► Inexpensive, fast and more environmentally friendly alternative for free glycerol determination in biodiesel ► Analyte extraction, sample clean up and use of toxic organic solvents are avoided. ► Ethanol as common solvent for biodiesel sample and aqueous chromogenic reagents ► It avoids drawbacks by incomplete extraction, analyte losses and sample contaminationA novel colorimetric and fluorescent sensor for fluoride and pyrophosphate based on fluorenone signaling units
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
T. Daniel Thangadurai, Chang Jun Lee, Su Hee Jeong, Sunghak Yoon, Yeong Geon Seo, Yong-Ill Lee
In this study, a novel chromogenic receptor, 1-(naphthalen-1-yl)-3-(9-oxo-9H-fluoren-1-yl)urea (1), utilizing fluorenone and naphthalene moieties as signaling groups was designed and synthesized. The interaction and colorimetric sensing properties of receptor 1 with different anions were investigated by the naked eye, as well as UV‐visible and fluorescence spectroscopy. The addition of 100 equiv. of fluoride and pyrophosphate as tetrabutylammonium salts to 1.25×10−4 M CH3CN:DMSO (9:1, v/v) solution mixture of receptor 1 produced a wine-red color. The oxoanions and a variety of other anions were not capable of producing any significant color change with receptor 1 under similar experimental conditions. The corresponding UV‐vis measurements showed a bathochromic shift of the 395nm band of receptor 1 to ~500nm for fluoride and pyrophosphate. Fluorescence emission changes indicate clearly that receptor 1 behaves like an ideal photo-induced electron transfer (PET) sensor upon complexation with anions. The limit of detection (LOD) of the sensor 1 is calculated to be ca. 250 and 110 nM for F− and HP2O7 3−, respectively. The 1H NMR titration studies shed further light on their mode of binding with receptor 1. The quantum mechanical calculations through time dependant density functional theory (TD-DFT) using basis set B3P86/TZVP support our experimental findings with a good agreement.
Source:Microchemical Journal, Volume 106
T. Daniel Thangadurai, Chang Jun Lee, Su Hee Jeong, Sunghak Yoon, Yeong Geon Seo, Yong-Ill Lee
In this study, a novel chromogenic receptor, 1-(naphthalen-1-yl)-3-(9-oxo-9H-fluoren-1-yl)urea (1), utilizing fluorenone and naphthalene moieties as signaling groups was designed and synthesized. The interaction and colorimetric sensing properties of receptor 1 with different anions were investigated by the naked eye, as well as UV‐visible and fluorescence spectroscopy. The addition of 100 equiv. of fluoride and pyrophosphate as tetrabutylammonium salts to 1.25×10−4 M CH3CN:DMSO (9:1, v/v) solution mixture of receptor 1 produced a wine-red color. The oxoanions and a variety of other anions were not capable of producing any significant color change with receptor 1 under similar experimental conditions. The corresponding UV‐vis measurements showed a bathochromic shift of the 395nm band of receptor 1 to ~500nm for fluoride and pyrophosphate. Fluorescence emission changes indicate clearly that receptor 1 behaves like an ideal photo-induced electron transfer (PET) sensor upon complexation with anions. The limit of detection (LOD) of the sensor 1 is calculated to be ca. 250 and 110 nM for F− and HP2O7 3−, respectively. The 1H NMR titration studies shed further light on their mode of binding with receptor 1. The quantum mechanical calculations through time dependant density functional theory (TD-DFT) using basis set B3P86/TZVP support our experimental findings with a good agreement.
Highlights
► A simple and novel “on–off” signal ensemble system for the selective detection of F− and HP2O7 3−. ► Design and synthesis of 1-(naphthalen-1-yl)-3-(9-oxo-9H-fluoren-1-yl)urea utilizing fluorenone and naphthalene moieties as signaling groups. ► Naked eye colorimetric sensing properties of receptor. ► Low detection limits for F− and HP2O7 3−.On-line preconcentration of zinc on ethyl vinyl acetate prior to its determination by CVG-ICP-OES
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
L.A. Escudero, S. Cerutti, L.D. Martinez, J.A. Salonia, J.A. Gasquez
A separation/preconcentration procedure using solid phase extraction coupled to zinc vapor generation associated to inductively coupled plasma optical emission spectrometry determination in water samples was studied. The solid phase material was ethyl vinyl acetate (EVA) contained in a column, where the analyte ions were retained without using any complexation agent. The variables involving the preconcentration and the chemical vapor generation (CVG) were optimized using both full factorial and central composite designs, respectively. Volatile species of zinc were generated by merging the acidified eluent and sodium tetrahydroborate in a continuous flow system. The gaseous analyte was introduced via a stream of Ar carrier into the inlet tube of the ICP torch. An enhancement factor of 230-fold for a sample volume of 16mL was obtained. The detection limit was 0.06μgL−1. The proposed method was successfully applied to the determination of traces of zinc in a Certified Reference Material and tap and river water samples.
Source:Microchemical Journal, Volume 106
L.A. Escudero, S. Cerutti, L.D. Martinez, J.A. Salonia, J.A. Gasquez
A separation/preconcentration procedure using solid phase extraction coupled to zinc vapor generation associated to inductively coupled plasma optical emission spectrometry determination in water samples was studied. The solid phase material was ethyl vinyl acetate (EVA) contained in a column, where the analyte ions were retained without using any complexation agent. The variables involving the preconcentration and the chemical vapor generation (CVG) were optimized using both full factorial and central composite designs, respectively. Volatile species of zinc were generated by merging the acidified eluent and sodium tetrahydroborate in a continuous flow system. The gaseous analyte was introduced via a stream of Ar carrier into the inlet tube of the ICP torch. An enhancement factor of 230-fold for a sample volume of 16mL was obtained. The detection limit was 0.06μgL−1. The proposed method was successfully applied to the determination of traces of zinc in a Certified Reference Material and tap and river water samples.
Highlights
► An on-line separation/preconcentration procedure using EVA has been coupled to the zinc vapor generation was studied. ► The zinc was retained as precipitate on the column without any complexing agent. ► Volatile species of zinc were generated with sodium tetrahydroborate in a continuous flow system. ► Multivariate techniques (two level factorial design and central composite design) were used for optimization of analytical methods. ► An enhancement factor of 230-fold was obtained and the detection limit was 0.06μgL−1.Mapping of corrosion products of highly altered archeological iron using voltammetry of microparticles
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Antonio Doménech, Montserrat Lastras, Francisco Rodríguez, Laura Osete
The application of the voltammetry of microparticles to identify corrosion products on different localizations of highly altered archeological iron pieces is described. The use of graphite pencil methodology permits to mapping different corrosion products, namely, akaganeite, goethite, hematite, jarosite, magnetite, maghemite and siderite, in iron artifacts. Identification protocols are based on square wave voltammetric measurements performed at sample-modified paraffin-impregnated graphite electrodes immersed into aqueous HCl. This methodology is applied for mapping corrosion products on an Iberian–Roman shield boss from the Torre la Sal archeological site (Oropesa, Spain) dated in the IVth century BC.
Source:Microchemical Journal, Volume 106
Antonio Doménech, Montserrat Lastras, Francisco Rodríguez, Laura Osete
The application of the voltammetry of microparticles to identify corrosion products on different localizations of highly altered archeological iron pieces is described. The use of graphite pencil methodology permits to mapping different corrosion products, namely, akaganeite, goethite, hematite, jarosite, magnetite, maghemite and siderite, in iron artifacts. Identification protocols are based on square wave voltammetric measurements performed at sample-modified paraffin-impregnated graphite electrodes immersed into aqueous HCl. This methodology is applied for mapping corrosion products on an Iberian–Roman shield boss from the Torre la Sal archeological site (Oropesa, Spain) dated in the IVth century BC.
Highlights
► Corrosion products on archeological iron are identified using voltammetry of microparticles. ► Individual components of mixtures can be identified. ► ‘One-touch’ sampling technique permits to map the distribution of such products in the surface of the artifacts.Support vector regression based QSPR for the prediction of retention time of pesticide residues in gas chromatography–mass spectroscopy
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Zahra Dashtbozorgi, Hassan Golmohammadi, Elahe Konoz
In this study, a quantitative structure–property relationship (QSPR) method was employed to predict the retention time (tR) of 368 pesticide residues in animal tissues separated by gas chromatography–mass spectroscopy (GC–MS). The variable selection method of genetic algorithm-partial least squares (GA-PLS) was employed to select most favorable subset of descriptors. The six descriptors selected using GA-PLS were used as inputs of PLS, ANN and SVM to predict the retention times. These descriptors are: number of nitrogen atoms, solvation connectivity index‐Chi 1, Balaban Y index, Moran autocorrelation‐lag 2/weighted by atomic Sanderson electronegativity, total absolute charge and radial distribution function-6.0/unweighted. The correlation coefficients, R, between experimental and predicted tR for the prediction set by PLS, ANN and SVM are 0.907, 0.963 and 0.985 respectively. Results obtained reveal the reliability and good predictability of nonlinear QSPR model to predict the retention time of pesticides. Comparison between the values of statistical parameters reveals the superiority of the SVM model over PLS and ANN ones.
Source:Microchemical Journal, Volume 106
Zahra Dashtbozorgi, Hassan Golmohammadi, Elahe Konoz
In this study, a quantitative structure–property relationship (QSPR) method was employed to predict the retention time (tR) of 368 pesticide residues in animal tissues separated by gas chromatography–mass spectroscopy (GC–MS). The variable selection method of genetic algorithm-partial least squares (GA-PLS) was employed to select most favorable subset of descriptors. The six descriptors selected using GA-PLS were used as inputs of PLS, ANN and SVM to predict the retention times. These descriptors are: number of nitrogen atoms, solvation connectivity index‐Chi 1, Balaban Y index, Moran autocorrelation‐lag 2/weighted by atomic Sanderson electronegativity, total absolute charge and radial distribution function-6.0/unweighted. The correlation coefficients, R, between experimental and predicted tR for the prediction set by PLS, ANN and SVM are 0.907, 0.963 and 0.985 respectively. Results obtained reveal the reliability and good predictability of nonlinear QSPR model to predict the retention time of pesticides. Comparison between the values of statistical parameters reveals the superiority of the SVM model over PLS and ANN ones.
Highlights
► Retention time of pesticide was modeled using QSPR approaches. ► GA-PLS was used to select the optimal subset of molecular descriptors. ► PLS, ANN and SVM were used for the prediction of retention time. ► The performances of the SVM model were superior to those of PLS and ANN ones.Metals in the water, sediment, and tissues of two fish species from different trophic levels in a subtropical Brazilian river
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Paula Weber, Everton Rodolfo Behr, Camila De Lellis Knorr, Daniel Secretti Vendruscolo, Erico M.M. Flores, Valderi L. Dressler, Bernardo Baldisserotto
In aquatic environments, heavy metals are produced from natural and anthropogenic sources and the degree of contamination in fish tissues depend on the pollutant type, fish species, sampling site, trophic level, and their mode of feeding. The heavy metal concentration (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Zn, and Pb) in the water, sediment, and liver of two fish species (Oligosarcus spp. – carnivore and Chyphocarax voga – detritivore) was analyzed at two sampling sites in the Sinos River, Brazil, during the four seasons. The highest heavy metals concentration was observed in the sediment, followed by water, and the lowest in fish. As the sediment was the major sink for pollution by metals in this river, it probably played an important role in the uptake of these metals by the detritivore species, which accumulated more metals in the liver than the carnivore species. Furthermore, the potential ecological risk was low for both sampling sites, showing the low metal contamination in this area.
Source:Microchemical Journal, Volume 106
Paula Weber, Everton Rodolfo Behr, Camila De Lellis Knorr, Daniel Secretti Vendruscolo, Erico M.M. Flores, Valderi L. Dressler, Bernardo Baldisserotto
In aquatic environments, heavy metals are produced from natural and anthropogenic sources and the degree of contamination in fish tissues depend on the pollutant type, fish species, sampling site, trophic level, and their mode of feeding. The heavy metal concentration (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Zn, and Pb) in the water, sediment, and liver of two fish species (Oligosarcus spp. – carnivore and Chyphocarax voga – detritivore) was analyzed at two sampling sites in the Sinos River, Brazil, during the four seasons. The highest heavy metals concentration was observed in the sediment, followed by water, and the lowest in fish. As the sediment was the major sink for pollution by metals in this river, it probably played an important role in the uptake of these metals by the detritivore species, which accumulated more metals in the liver than the carnivore species. Furthermore, the potential ecological risk was low for both sampling sites, showing the low metal contamination in this area.
Highlights
► We analyzed two sampling sites with different pollution degree in the same River. ► For both sites, metal concentration was highest in the sediment, middle in water, and lower in the fish liver. ► The detritivore species presented the highest concentration for all analyzed metals. ► Potential ecological risk for single regulator indexes showed low potential ecological risk for all analyzed metals except Cd.Diagnosis of renal failure by infrared spectrometric analysis of human serum samples and soft independent modeling of class analogy
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Mohammadreza Khanmohammadi, Amir Bagheri Garmarudi, Mehdi Ramin, Keyvan Ghasemi
Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy has been used in this research for reagent-free discrimination of serum samples obtained from healthy people and those with renal failure. No sample preparation step e.g. drying or pre-concentration is required prior to spectral analysis. Classification was performed based on the spectral variations in patient samples. In the experimental step, 75 blood serum samples, including 40 normal and 35 renal failure cases, were analyzed in 1800–900cm−1 spectral region. Unsupervised pattern recognition of the serum samples using cluster analysis (CA) and principal component analysis (PCA), did not demonstrate any useful capability of these techniques for discrimination aims. Supervised pattern recognition using soft independent modeling of class analogy (SIMCA) was performed. Results showed 95.12% of accuracy in ATR-FTIR diagnostic results being compared with the current clinical methods. The sensitivity and specificity of the proposed method are 100% and 91.3%, respectively.
Source:Microchemical Journal, Volume 106
Mohammadreza Khanmohammadi, Amir Bagheri Garmarudi, Mehdi Ramin, Keyvan Ghasemi
Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy has been used in this research for reagent-free discrimination of serum samples obtained from healthy people and those with renal failure. No sample preparation step e.g. drying or pre-concentration is required prior to spectral analysis. Classification was performed based on the spectral variations in patient samples. In the experimental step, 75 blood serum samples, including 40 normal and 35 renal failure cases, were analyzed in 1800–900cm−1 spectral region. Unsupervised pattern recognition of the serum samples using cluster analysis (CA) and principal component analysis (PCA), did not demonstrate any useful capability of these techniques for discrimination aims. Supervised pattern recognition using soft independent modeling of class analogy (SIMCA) was performed. Results showed 95.12% of accuracy in ATR-FTIR diagnostic results being compared with the current clinical methods. The sensitivity and specificity of the proposed method are 100% and 91.3%, respectively.
Highlights
► FTIR spectroscopic approach for analysis of human blood serum samples as a new method for diagnosis of renal failure ► Diagnosis with no sample preparation ► Rapid, precise and accurate ► Taking into account the medical interest of statistical parameters ► Capable of being developed for medical usual applicationEstimation of naturally occurring radionuclides in fertilizers using gamma spectrometry and elemental analysis by XRF and XRD techniques
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Pooja Chauhan, R.P. Chauhan, Monika Gupta
The fertilizers are essential in agriculture as they supply nutrients to the farming fields. One of the sources of radioactivity other than those of natural origin is mainly due to extensive use of fertilizers. The concentrations of natural radionuclides, namely 226Ra,232Th and 40K in different chemical fertilizers used in agricultural soil were analyzed using gamma spectrometry with a high purity germanium (HPGe) detector in order to assess the implications of the extended use of phosphate fertilizers in recent years. The radiological impact assessment in an integrated manner assessing doses to members of the public via the atmospheric aquatic and secondary pathways was made. The concentration of major elements (AI2O3, SiO2, P2O5, SO3, CI, K2O, Fe2O3) along with other elements present in all samples were measured by X-ray fluorescence (XRF) analysis. The X-ray diffraction (XRD) system was used for analyzing the composition of fertilizer samples. The XRD results confirmed the presence of main constituents fluorapatite Ca5(PO4)3F, hydroxylapatite Ca5(PO4)3(OH) and chlorapatite Ca5(PO4)3CI of phosphate fertilizer samples.
Source:Microchemical Journal, Volume 106
Pooja Chauhan, R.P. Chauhan, Monika Gupta
The fertilizers are essential in agriculture as they supply nutrients to the farming fields. One of the sources of radioactivity other than those of natural origin is mainly due to extensive use of fertilizers. The concentrations of natural radionuclides, namely 226Ra,232Th and 40K in different chemical fertilizers used in agricultural soil were analyzed using gamma spectrometry with a high purity germanium (HPGe) detector in order to assess the implications of the extended use of phosphate fertilizers in recent years. The radiological impact assessment in an integrated manner assessing doses to members of the public via the atmospheric aquatic and secondary pathways was made. The concentration of major elements (AI2O3, SiO2, P2O5, SO3, CI, K2O, Fe2O3) along with other elements present in all samples were measured by X-ray fluorescence (XRF) analysis. The X-ray diffraction (XRD) system was used for analyzing the composition of fertilizer samples. The XRD results confirmed the presence of main constituents fluorapatite Ca5(PO4)3F, hydroxylapatite Ca5(PO4)3(OH) and chlorapatite Ca5(PO4)3CI of phosphate fertilizer samples.
Highlights
► The present study is related to the analysis of different fertilizer samples. ► Natural radioactivity has been estimated using HPGe detector. ► The elemental analysis was carried out using XRF. ► The composition has been analyzed by XRD.Estimation of polycyclic aromatic hydrocarbons associated with size segregated combustion aerosols generated from household fuels
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
M. Tiwari, S.K. Sahu, R.C. Bhangare, P.Y. Ajmal, G.G. Pandit
Combustion of household fuels is the major source of polycyclic aromatic hydrocarbons (PAHs) in indoor environment. The quantity and quality of PAHs in indoor environment depend on the choice of household fuels and combustion conditions (ventilation, stove type, moisture content of fuel, etc.). In present study, the mass size distribution of combustion aerosol and size fractionated PAHs (sixteen) was evaluated for most commonly used household fuels viz. firewood, coal, dung cake, kerosene and LPG. Variable configuration cascade impactor (VCCI) was used for aerosol collection, and subsequent analysis of PAHs was carried out using high performance liquid chromatography (HPLC) coupled with UV detector. For solid fuels (firewood, coal, dung cake) mass concentration was found maximum in accumulation mode i.e., size range 0.75–2.23μm. The kerosene and LPG generated aerosols were found to be distributed all over the measured size bin (>21 to <0.1μm). It was found that most of the PAHs are associated with 0.75–1.13μm size range of particle for combustion aerosols. Firewood, coal and kerosene emit maximum PAHs associated with fine fraction, while PAH content for LPG was found to be more or less same in all size fractions. Solid biomass generates more higher molecular weight (five or more rings) PAHs compared to non-solid fuels such as kerosene and LPG, while the latter are mainly emitting two and three ring PAHs. The formation of multiple ring PAHs is a function of combustion temperature which may vary according to fuel type and methods of combustion. Data of PAH contents in different size fraction of tested fuels can be used for PAH markers.
Source:Microchemical Journal, Volume 106
M. Tiwari, S.K. Sahu, R.C. Bhangare, P.Y. Ajmal, G.G. Pandit
Combustion of household fuels is the major source of polycyclic aromatic hydrocarbons (PAHs) in indoor environment. The quantity and quality of PAHs in indoor environment depend on the choice of household fuels and combustion conditions (ventilation, stove type, moisture content of fuel, etc.). In present study, the mass size distribution of combustion aerosol and size fractionated PAHs (sixteen) was evaluated for most commonly used household fuels viz. firewood, coal, dung cake, kerosene and LPG. Variable configuration cascade impactor (VCCI) was used for aerosol collection, and subsequent analysis of PAHs was carried out using high performance liquid chromatography (HPLC) coupled with UV detector. For solid fuels (firewood, coal, dung cake) mass concentration was found maximum in accumulation mode i.e., size range 0.75–2.23μm. The kerosene and LPG generated aerosols were found to be distributed all over the measured size bin (>21 to <0.1μm). It was found that most of the PAHs are associated with 0.75–1.13μm size range of particle for combustion aerosols. Firewood, coal and kerosene emit maximum PAHs associated with fine fraction, while PAH content for LPG was found to be more or less same in all size fractions. Solid biomass generates more higher molecular weight (five or more rings) PAHs compared to non-solid fuels such as kerosene and LPG, while the latter are mainly emitting two and three ring PAHs. The formation of multiple ring PAHs is a function of combustion temperature which may vary according to fuel type and methods of combustion. Data of PAH contents in different size fraction of tested fuels can be used for PAH markers.
Highlights
► Order of mass concentration emission was dung cake>firewood>coal>kerosene>LPG. ► Order of PAH emission was found to be dung cake>firewood>coal>LPG>kerosene. ► Most of the PAHs were associated with 0.75–1.13μm size range of combustion aerosols. ► Solid fuels viz. firewood, dung cake, coal emitted high molecular weight (>5 rings) PAHs. ► Non-solid fuels like kerosene and LPG emitted lower molecular weight (2–3 rings) PAHs.Multi-technique chemical characterisation of a 12–13th-century painted Crucifix
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Inez D. van der Werf, Cosima D. Calvano, Rocco Laviano, Antonella Simonetti, Luigia Sabbatini
The Crucifix panel painting in the Santa Maria a Mare church on the Isle of St. Nicholas (Isole Tremiti, Italy), painted on both sides, was executed between the late 12th century and the early 13th century and several times restored in the following centuries. The precious artefact was studied by various complementary analytical techniques in order to characterize the original medieval painting technique and the subsequently applied restoration materials. Optical microscopy (OM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), micro-Raman spectroscopy, pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and Matrix Assisted Laser Desorption Ionisation–Time of Flight–Mass Spectrometry (MALDI-TOF-MS) were applied on various samples taken from significant parts of the painting. The compositional data were used for a correct planning of the recent restoration treatments and as a support for the historical-artistic study of the painting. The results obtained confirm that both paintings—recto and verso—were realized by following the 13th century Italian painting tradition. Egg-based paint layers were applied on a gypsum/animal glue ground. Various pigments could be identified among which the precious lapis lazuli. Interestingly, the water-gilding of the recto was performed without the use of a bole layer. Pinaceae resin as well as acrylic resins were found.
Source:Microchemical Journal, Volume 106
Inez D. van der Werf, Cosima D. Calvano, Rocco Laviano, Antonella Simonetti, Luigia Sabbatini
The Crucifix panel painting in the Santa Maria a Mare church on the Isle of St. Nicholas (Isole Tremiti, Italy), painted on both sides, was executed between the late 12th century and the early 13th century and several times restored in the following centuries. The precious artefact was studied by various complementary analytical techniques in order to characterize the original medieval painting technique and the subsequently applied restoration materials. Optical microscopy (OM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), micro-Raman spectroscopy, pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and Matrix Assisted Laser Desorption Ionisation–Time of Flight–Mass Spectrometry (MALDI-TOF-MS) were applied on various samples taken from significant parts of the painting. The compositional data were used for a correct planning of the recent restoration treatments and as a support for the historical-artistic study of the painting. The results obtained confirm that both paintings—recto and verso—were realized by following the 13th century Italian painting tradition. Egg-based paint layers were applied on a gypsum/animal glue ground. Various pigments could be identified among which the precious lapis lazuli. Interestingly, the water-gilding of the recto was performed without the use of a bole layer. Pinaceae resin as well as acrylic resins were found.
Highlights
► A medieval panel painting was studied with complementary analytical techniques. ► Py-GC/MS allowed for identification of synthetic resins as used in restoration. ► MALDI-MS analysis showed the occurrence of aged egg binder and animal glue. ► Painting techniques and pigments were studied with MO, SEM and micro-Raman.Determination of tributyltin at parts-per-trillion levels in natural waters by second-order multivariate calibration and fluorescence spectroscopy
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Manuel Bravo M., Luis F. Aguilar, Waldo Quiroz V., Alejandro C. Olivieri, Graciela M. Escandar
This work presents a non-sophisticated approach for the trace determination of tributyltin, the most toxic organotin species, in very interfering environments, combining fluorescence measurements of its morin complex and the selectivity of second-order chemometric algorithms. The power of MCR–ALS (multivariate curve resolution/alternating least-squares) to quantify tributyltin through fluorescence excitation–emission matrices in the presence of its main degradation products and of a pool of additional twenty-three metal ions is demonstrated. The applied algorithm successfully faces the challenge of solving the strong overlapping among the spectra of the several sample components. The proposed methodology was applied to tap, river, lagoon and seawater spiked samples, obtaining satisfactory results at ngL−1 levels, after a pre-concentration step on a C18 membrane, demonstrating the analytical potential of the proposed methodology.
Source:Microchemical Journal, Volume 106
Manuel Bravo M., Luis F. Aguilar, Waldo Quiroz V., Alejandro C. Olivieri, Graciela M. Escandar
This work presents a non-sophisticated approach for the trace determination of tributyltin, the most toxic organotin species, in very interfering environments, combining fluorescence measurements of its morin complex and the selectivity of second-order chemometric algorithms. The power of MCR–ALS (multivariate curve resolution/alternating least-squares) to quantify tributyltin through fluorescence excitation–emission matrices in the presence of its main degradation products and of a pool of additional twenty-three metal ions is demonstrated. The applied algorithm successfully faces the challenge of solving the strong overlapping among the spectra of the several sample components. The proposed methodology was applied to tap, river, lagoon and seawater spiked samples, obtaining satisfactory results at ngL−1 levels, after a pre-concentration step on a C18 membrane, demonstrating the analytical potential of the proposed methodology.
Highlights
► Toxic tributyltin was pre-concentrated on C18 membranes from water samples. ► Excitation–emission fluorescence matrices were measured after morin complexing. ► Multivariate curve resolution was applied for data processing. ► The strong spectral overlapping was resolved by the algorithm. ► Tributyltin traces were quantitated in the presence of uncalibrated interferences.Development of an electroanalytical method for the determination of lead in Argentina raw propolis based on bismuth electrodes
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Gastón Darío Pierini, Adrian Marcelo Granero, María Susana Di Nezio, María Eugenia Centurión, María Alicia Zon, Héctor Fernández
Propolis is a honeybee product which contains lead as one of the main contaminants. Taking into account that this product is used in the food industry, the Código Alimentario Argentino establishes maximum allowable level for raw propolis. Therefore, in this study an electroanalytical method to determine this metal in Argentina raw propolis samples was developed. A bismuth film electrode plated on a modified glassy carbon electrode was prepared. The use of these electrodes has been proposed as an alternative to mercury film electrodes in electroanalytical chemistry due to low toxicity of bismuth (environmentally friendly metal). The method presents a linear range between 1 and 50μgL−1 of Pb(II). The limits of detection and quantification were 0.6μgL−1 and 1.84μgL−1, respectively. The reproducibility and repeatability calculated as the relative standard deviations were 7.4% and 7.0%, respectively. The sample throughput was 21sampleh−1. Argentina raw propolis samples were analyzed and some of them showed high levels of lead. The obtained results with this method are in good agreement with that obtained with the ICP-AES technique. Moreover, it is a good alternative to the quality control of raw propolis.
Source:Microchemical Journal, Volume 106
Gastón Darío Pierini, Adrian Marcelo Granero, María Susana Di Nezio, María Eugenia Centurión, María Alicia Zon, Héctor Fernández
Propolis is a honeybee product which contains lead as one of the main contaminants. Taking into account that this product is used in the food industry, the Código Alimentario Argentino establishes maximum allowable level for raw propolis. Therefore, in this study an electroanalytical method to determine this metal in Argentina raw propolis samples was developed. A bismuth film electrode plated on a modified glassy carbon electrode was prepared. The use of these electrodes has been proposed as an alternative to mercury film electrodes in electroanalytical chemistry due to low toxicity of bismuth (environmentally friendly metal). The method presents a linear range between 1 and 50μgL−1 of Pb(II). The limits of detection and quantification were 0.6μgL−1 and 1.84μgL−1, respectively. The reproducibility and repeatability calculated as the relative standard deviations were 7.4% and 7.0%, respectively. The sample throughput was 21sampleh−1. Argentina raw propolis samples were analyzed and some of them showed high levels of lead. The obtained results with this method are in good agreement with that obtained with the ICP-AES technique. Moreover, it is a good alternative to the quality control of raw propolis.
Highlights
►Argentina raw propolis meets basic requirements for export. ►Argentina law establishes the maximum lead level in raw propolis of 2.0mgkg−1. ►A square wave anodic stripping voltammetry method to determine lead was developed. ►A bismuth electrode prepared in situ on modified glassy carbon electrodes was used. ►This method is a good alternative for the quality control of Argentina raw propolis.A new methodological approach to assess the mobility of As, Cd, Co, Cr, Cu, Fe, Ni and Pb in river sediments
12 November 2012,
09:44:03
Publication year:
2013
Source:Microchemical Journal, Volume 106
Unai Villanueva, Juan C. Raposo, Juan M. Madariaga
Extraction tests are commonly used to study the mobility of trace metals in soils and sediments by mimicking different environmental conditions but the results obtained by determining the extractable elements are dependent on the extraction procedure applied. The variety of extraction procedures used makes it very difficult to compare the results obtained; therefore, harmonisation and standardisation is required. In this work, two different extraction methods were tested to determine the mobility or persistence of eight trace metals in river sediments: (a) extraction with NH4NO3 1.0molL−1 (as the German DIN 19730 norm defines) and (b) extraction using the own water in contact with the river sediment collected in different locations of the Basque Country (North of Spain). The effect of sampling sites properties and different physico-chemical factors mainly pH and ORP on the mobilisation processes were analysed by means of chemometrical methods. As a conclusion, NH4NO3 extraction was disregarded because artificial higher mobility values for As, Co, Cr and Cu were obtained by promoting the formation of ammoniacal complexes. As a result, a new methodology was assessed in this work by assumption that the river water used as extractant is more useful and realistic in order to evaluate the natural capacity of the river water to mobilise trace metals from the sediments. The mobilisation experiment conclusions were also supported by Raman spectroscopy measurements of the river sediments. The presence of carbonates (aragonite and calcite) and sodium sulphide were probably the responsible to define the pH profiles obtained during the mobility experiments for each sampling site.
Source:Microchemical Journal, Volume 106
Unai Villanueva, Juan C. Raposo, Juan M. Madariaga
Extraction tests are commonly used to study the mobility of trace metals in soils and sediments by mimicking different environmental conditions but the results obtained by determining the extractable elements are dependent on the extraction procedure applied. The variety of extraction procedures used makes it very difficult to compare the results obtained; therefore, harmonisation and standardisation is required. In this work, two different extraction methods were tested to determine the mobility or persistence of eight trace metals in river sediments: (a) extraction with NH4NO3 1.0molL−1 (as the German DIN 19730 norm defines) and (b) extraction using the own water in contact with the river sediment collected in different locations of the Basque Country (North of Spain). The effect of sampling sites properties and different physico-chemical factors mainly pH and ORP on the mobilisation processes were analysed by means of chemometrical methods. As a conclusion, NH4NO3 extraction was disregarded because artificial higher mobility values for As, Co, Cr and Cu were obtained by promoting the formation of ammoniacal complexes. As a result, a new methodology was assessed in this work by assumption that the river water used as extractant is more useful and realistic in order to evaluate the natural capacity of the river water to mobilise trace metals from the sediments. The mobilisation experiment conclusions were also supported by Raman spectroscopy measurements of the river sediments. The presence of carbonates (aragonite and calcite) and sodium sulphide were probably the responsible to define the pH profiles obtained during the mobility experiments for each sampling site.
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