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María Fernanda Silva - One of the best experts on this subject based on the ideXlab platform.
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Determination of Seleno-Amino Acids bound to proteins in extra virgin olive oils.
Food chemistry, 2015Co-Authors: Sabier Torres, Raúl A. Gil, María Fernanda Silva, Pablo H. PachecoAbstract:An analytical method has been developed to determine Seleno-Amino Acids in proteins extracted from extra virgin olive oils (EVOOs). Different aqueous/organic solvents were tested to isolate proteins, an acetone:n-hexane combination being the best protein precipitant. In a first dimension chromatography, extracted proteins were analysed by size exclusion chromatography (SEC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) to identify S and Se associations as proteins marker. Two fractions of 66 kDa (A) and 443 kDa (B) were identified. These fractions were submitted to microwave-assisted acid hydrolysis (MAAH) to release Seleno-Amino Acids. In a second dimension chromatography Seleno-Amino Acids were determined by reversed-phase chromatography (RPC) coupled to ICP-MS. Seleno-methylSelenocysteine was determined with values ranging from 1.03-2.03±0.2 μg kg(-1) and Selenocysteine at a concentration of 1.47±0.1 μg kg(-1). Variations of protein and Seleno-Amino acid concentrations were observed between EVOO varieties, contributing to EVOO cultivar differentiation.
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preconcentration of Seleno Amino Acids on a xad resin and determination in regional olive oils by spe uplc esi ms ms
Food Chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
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Preconcentration of Seleno-Amino Acids on a XAD resin and determination in regional olive oils by SPE UPLC-ESI-MS/MS.
Food chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
Pablo H. Pacheco - One of the best experts on this subject based on the ideXlab platform.
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Green and simple extraction of free Seleno-Amino Acids from powdered and lyophilized milk samples with natural deep eutectic solvents.
Food chemistry, 2020Co-Authors: Romina V. Lucero López, Soledad Cerutti, Roberto D’amato, Massimo Trabalza-marinucci, Luca Regni, Primo Proetti, Ariel Maratta, Pablo H. PachecoAbstract:Abstract Natural deep eutectic solvents (NADES) were introduced for the extraction of free Seleno-Amino Acids from lyophilized and powdered milk samples. Different NADES were evaluated, and lactic acid:glucose (LGH) showed the highest selenium recoveries. Selenium analysis was performed by inductively coupled plasma mass spectrometry (ICP MS). Se-NADES analysis in ICP MS was optimized according to the radio frequency power and nebulization gas flow rate. Se-NADES extraction was optimized by an experimental design. LGH dilution, LGH volume, sample quantity, and ultrasound time were factors influencing the extraction. Seleno-Amino Acids were determined by liquid chromatography-ICP MS. After optimization, the limits of detection obtained were 7.37, 8.63, and 9.64 µg kg−1 for Selenocysteine, Selenomethionine, and Seleno-methyl-Selenocysteine, respectively. The NADES-extraction is a green procedure with 2 penalty points in the EcoScale. The method was applied to the analysis of powdered milk, lyophilized Se-fortified sheep milk, and ERM-BD151 skimmed milk powder.
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Determination of Seleno-Amino Acids bound to proteins in extra virgin olive oils.
Food chemistry, 2015Co-Authors: Sabier Torres, Raúl A. Gil, María Fernanda Silva, Pablo H. PachecoAbstract:An analytical method has been developed to determine Seleno-Amino Acids in proteins extracted from extra virgin olive oils (EVOOs). Different aqueous/organic solvents were tested to isolate proteins, an acetone:n-hexane combination being the best protein precipitant. In a first dimension chromatography, extracted proteins were analysed by size exclusion chromatography (SEC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) to identify S and Se associations as proteins marker. Two fractions of 66 kDa (A) and 443 kDa (B) were identified. These fractions were submitted to microwave-assisted acid hydrolysis (MAAH) to release Seleno-Amino Acids. In a second dimension chromatography Seleno-Amino Acids were determined by reversed-phase chromatography (RPC) coupled to ICP-MS. Seleno-methylSelenocysteine was determined with values ranging from 1.03-2.03±0.2 μg kg(-1) and Selenocysteine at a concentration of 1.47±0.1 μg kg(-1). Variations of protein and Seleno-Amino acid concentrations were observed between EVOO varieties, contributing to EVOO cultivar differentiation.
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preconcentration of Seleno Amino Acids on a xad resin and determination in regional olive oils by spe uplc esi ms ms
Food Chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
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Preconcentration of Seleno-Amino Acids on a XAD resin and determination in regional olive oils by SPE UPLC-ESI-MS/MS.
Food chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
Sabier Torres - One of the best experts on this subject based on the ideXlab platform.
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Determination of Seleno-Amino Acids bound to proteins in extra virgin olive oils.
Food chemistry, 2015Co-Authors: Sabier Torres, Raúl A. Gil, María Fernanda Silva, Pablo H. PachecoAbstract:An analytical method has been developed to determine Seleno-Amino Acids in proteins extracted from extra virgin olive oils (EVOOs). Different aqueous/organic solvents were tested to isolate proteins, an acetone:n-hexane combination being the best protein precipitant. In a first dimension chromatography, extracted proteins were analysed by size exclusion chromatography (SEC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) to identify S and Se associations as proteins marker. Two fractions of 66 kDa (A) and 443 kDa (B) were identified. These fractions were submitted to microwave-assisted acid hydrolysis (MAAH) to release Seleno-Amino Acids. In a second dimension chromatography Seleno-Amino Acids were determined by reversed-phase chromatography (RPC) coupled to ICP-MS. Seleno-methylSelenocysteine was determined with values ranging from 1.03-2.03±0.2 μg kg(-1) and Selenocysteine at a concentration of 1.47±0.1 μg kg(-1). Variations of protein and Seleno-Amino acid concentrations were observed between EVOO varieties, contributing to EVOO cultivar differentiation.
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preconcentration of Seleno Amino Acids on a xad resin and determination in regional olive oils by spe uplc esi ms ms
Food Chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
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Preconcentration of Seleno-Amino Acids on a XAD resin and determination in regional olive oils by SPE UPLC-ESI-MS/MS.
Food chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
M. Lamotte - One of the best experts on this subject based on the ideXlab platform.
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Determination of the Deprotonation Constants of Seleno-DL-cystine and Seleno-DL-methionine and Implication to their Separation by HPLC
Applied Organometallic Chemistry, 1997Co-Authors: M.r. Da Silva, R. Muños Olivas, O.f.x. Donard, M. LamotteAbstract:We have determined the deprotonation constants (pKa) of Seleno-DL-cystine and Seleno-DL-methionine together with those of DL-cystine and DL-methionine for comparison, by potentiometric measurements. In the case of Seleno-DL-cystine, the difference between the pKa values for the two Amino groups was found to be only slightly lower than that observed for DL-cystine itself. In contrast, the difference between the two pKa values for the carboxylic groups was found to be much smaller for Seleno-DL-cystine than for DL-cystine. In both Seleno-Amino-Acids, the zwitterionic species appear to be dominant in the pH range between 4 and 7, while positively charged protonated species are found to be present at pH values lower than 4. Based on a knowledge of the ionic species distributions as a function of pH, we have proposed an interpretation for the Chromatographic separation of Selenocystine and Selenomethionine by HPLC. © 1997 by John Wiley & Sons, Ltd.
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Determination of the deprotonation constants of Seleno‐DL‐cystine and Seleno‐DL‐methionine and implication to their separation by HPLC
Applied Organometallic Chemistry, 1997Co-Authors: M.r. Da Silva, O.f.x. Donard, Riansares Muños Olivas, M. LamotteAbstract:We have determined the deprotonation constants (pKa) of Seleno-DL-cystine and Seleno-DL-methionine together with those of DL-cystine and DL-methionine for comparison, by potentiometric measurements. In the case of Seleno-DL-cystine, the difference between the pKa values for the two Amino groups was found to be only slightly lower than that observed for DL-cystine itself. In contrast, the difference between the two pKa values for the carboxylic groups was found to be much smaller for Seleno-DL-cystine than for DL-cystine. In both Seleno-Amino-Acids, the zwitterionic species appear to be dominant in the pH range between 4 and 7, while positively charged protonated species are found to be present at pH values lower than 4. Based on a knowledge of the ionic species distributions as a function of pH, we have proposed an interpretation for the chromatographic separation of Selenocystine and Selenomethionine by HPLC. © 1997 by John Wiley & Sons, Ltd.
Soledad Cerutti - One of the best experts on this subject based on the ideXlab platform.
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Green and simple extraction of free Seleno-Amino Acids from powdered and lyophilized milk samples with natural deep eutectic solvents.
Food chemistry, 2020Co-Authors: Romina V. Lucero López, Soledad Cerutti, Roberto D’amato, Massimo Trabalza-marinucci, Luca Regni, Primo Proetti, Ariel Maratta, Pablo H. PachecoAbstract:Abstract Natural deep eutectic solvents (NADES) were introduced for the extraction of free Seleno-Amino Acids from lyophilized and powdered milk samples. Different NADES were evaluated, and lactic acid:glucose (LGH) showed the highest selenium recoveries. Selenium analysis was performed by inductively coupled plasma mass spectrometry (ICP MS). Se-NADES analysis in ICP MS was optimized according to the radio frequency power and nebulization gas flow rate. Se-NADES extraction was optimized by an experimental design. LGH dilution, LGH volume, sample quantity, and ultrasound time were factors influencing the extraction. Seleno-Amino Acids were determined by liquid chromatography-ICP MS. After optimization, the limits of detection obtained were 7.37, 8.63, and 9.64 µg kg−1 for Selenocysteine, Selenomethionine, and Seleno-methyl-Selenocysteine, respectively. The NADES-extraction is a green procedure with 2 penalty points in the EcoScale. The method was applied to the analysis of powdered milk, lyophilized Se-fortified sheep milk, and ERM-BD151 skimmed milk powder.
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Optimisation of microwave-assisted acid hydrolysis for the determination of Seleno-Amino Acids bound to proteins in powdered milk, lyophilized milk and infant formula
Journal of Food Composition and Analysis, 2019Co-Authors: Romina V. Lucero López, Soledad Cerutti, Roberto D’amato, Massimo Trabalza-marinucci, Luis Escudero, Daniela Businelli, Pablo PachecoAbstract:Abstract Selenium (Se) is an essential element present in milk as Seleno-Amino Acids and Seleno-proteins. To perform an accurate Seleno-Amino acid analysis, a complete hydrolysis of proteins is necessary. Microwave-assisted acid hydrolysis (MAAH) can be used; however, some variables must be optimised to avoid incomplete hydrolysis and oxidation. Multivariate calibration showed that the volume of the reducing agent, the concentration of the acid used, and the microwave power were statistically significant (95% confidence), and since these are the variables controlling the system, a final optimisation was performed to increase the method efficiency. This was performed using a 2(4−1) central composite design. A robustness study was performed employing the Taguchi design, which demonstrated that the optimised MAAH technique was not dependent on the protein concentration of the milk samples. Following MAAH optimisation, a 30-fold recovery improvement was obtained for Seleno-Amino Acids, reaching a limit of detection of 0.053 μg 100g−1 for Selenocysteine. Selenocysteine, Selenomethionine, and Seleno-methyl-Selenocysteine were determined at concentration ranges of 5.06 ± 0.20–22.5 ± 0.90, 0.75 ± 0.03–19.7 ± 1.2 and 1.25 ± 0.05–16.3 ± 0.85 respectively, in commercial powder milk samples and infant formula, lyophilized selenium-enriched ewe milk, lyophilized human milk and reference material ERM-BD150 skimmed milk powder.
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preconcentration of Seleno Amino Acids on a xad resin and determination in regional olive oils by spe uplc esi ms ms
Food Chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.
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Preconcentration of Seleno-Amino Acids on a XAD resin and determination in regional olive oils by SPE UPLC-ESI-MS/MS.
Food chemistry, 2014Co-Authors: Sabier Torres, Pablo H. Pacheco, Soledad Cerutti, Julio Raba, María Fernanda SilvaAbstract:Abstract This study describes a method for Seleno-Amino Acids determination in Argentinean olive oils. Preliminary total selenium determination in olive oils probed low concentrations (62.8 ± 1.6 to 117.4 ± 3.0 μg/kg) and the necessity of implementing a preconcentration method. To this end a XAD® resin was employed as sorbent for Selenomethionine (Se-Met), SelenomethylSelenocysteine (Se-MetSeCys), and Selenocysteine (Se-Cys) preconcentration. Determinations were performed by UPLC–ESI-MS/MS. Recoveries were between 84% and 97% for the Seleno-Amino Acids studied, reaching a detection limit of 0.09 μg/kg, a precision of 10% (RSD, n = 6), and an enhancement factor of 60-fold (6 for the extraction system and 10 for the preconcentration approach). The only detected Se species in the olive oils was Se-MetSeCys in concentrations ranging from 2.0 to 8.3 μg/kg.