The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Pilar Campíns-falcó - One of the best experts on this subject based on the ideXlab platform.
-
An evaluation of solid phase microextraction for aliphatic amines using derivatization with 9-Fluorenylmethyl Chloroformate and liquid chromatography.
Journal of chromatography. A, 2006Co-Authors: Rosa Herráez-hernández, C Cháfer-pericás, J Verdú-andrés, Pilar Campíns-falcóAbstract:The reliability of SPME combined with a chemical reaction for the analysis of short-chain aliphatic amines by liquid chromatography has been investigated. Different options to couple SPME and derivatization have been tested and compared: (i) derivatization of the analytes in solution followed by the extraction of the derivatives, (ii) extraction of the analytes and subsequent derivatization by immersing the SPME fibre onto a solution of the reagent, and (iii) extraction/derivatization of the analytes using fibres previously coated with the reagent. Methylamine (MA), dimethylamine (DMA) and trimethylamine (TMA) have been selected as a model of primary, secondary and tertiary amines, respectively. The analytes have been derivatized with the fluorogenic reagent 9-Fluorenylmethyl Chloroformate (FMOC), and the fibre coating was Carbowax-templated resin (CW-TR). The employment of fibres coated with FMOC to extract and derivatize the analytes was the best option, as compared with the other approaches tested the sensitivity was considerably improved. On the basis of these studies, a new procedure for the determination of MA, DMA and TMA in water is presented. To demonstrate the utility of the proposed conditions data on linearity, accuracy, repeatability and sensitivity are given. Results of the determination of the amines in tap, river and waste water are also presented.
-
A new selective method for dimethylamine in water analysis by liquid chromatography using solid-phase microextraction and two-stage derivatization with o-phthalaldialdehyde and 9-Fluorenylmethyl Chloroformate.
Talanta, 2005Co-Authors: Consuelo Cháfer-pericás, Rosa Herráez-hernández, Pilar Campíns-falcóAbstract:Abstract A new method is presented for the determination of DMA in water as its 9-Fluorenylmethyl Chloroformate (FMOC) derivative using solid-phase microextraction (SPME) and liquid chromatography. The method is based on the employment of SPME fibres coated with carbowax-templated resin (CW-TR) for analyte extraction and derivatization. The fibres were successively immersed in the samples, in a solution of o -phthalaldialdehyde and N -acethyl- l -cysteine (OPA–NAC) and finally, in a solution of FMOC. OPA–NAC reacted on the fibre with possible primary aliphatic amines present in the samples, particularly with PA which is a direct interferent in the determination of DMA with FMOC. In such a way, the formation of PA–FMOC during the second stage was prevented, and thus the method was selective for DMA. The proposed procedure was applied to the determination of DMA in the 1.0–10.0 μg/mL range. The method provided suitable linearity, accuracy and reproducibility, and limits of detection and quantification of 0.3 and 1.0 μg/mL, respectively. The applicability of the method for the determination of DMA in different types of water is shown.
-
Analysis of methylamine by solid-phase microextraction and HPLC after on-fibre derivatization with 9-Fluorenylmethyl Chloroformate
Analytica Chimica Acta, 2004Co-Authors: Rosa Herráez-hernández, Consuelo Cháfer-pericás, Pilar Campíns-falcóAbstract:Abstract A method for the determination of methylamine (MA) in aqueous matrices is reported which uses solid-phase microextraction (SPME) for enrichment and derivatization of the analyte, and high performance liquid chromatography (HPLC). The fluorogenic reagent 9-Fluorenylmethyl Chloroformate (FMOC) has been used for derivatization. The SPME fibres were successively immersed in the samples and in the derivatization solutions to extract MA and FMOC, respectively. After a defined time of reaction, the derivatized analyte was desorbed into the chromatographic system, and chromatographed in a LiChrosphere 100 RP18, 125 mm ×4 mm i.d., 5 μm, column under gradient elution. In order to improve the MA-FMOC peak profile, a precolumn ( 20 mm ×2.1 mm i.d., packed with Hypersil C18 phase, 30 μm) was connected on-line to the analytical column by means of a switching valve. The experimental conditions (including fibre coating, times of adsorption, reaction and desorption, and concentration of reagent) have been optimised, and the results have been compared with those achieved by using a method previously validated for aliphatic amines in which extraction and derivatization were carried into C18 solid-phase extraction (SPE) cartridges. Although less sensitive, the SPME based method allowed the quantification of MA over the range 2.5–10.0 μg/ml with linearity, reproducibility and accuracy comparable to that of the SPE based method, the limit of detection being 0.75 μg/ml. The main advantages of the proposed SPME procedure are: sample handling involved in the extraction and derivatization steps was considerably reduced, it was free organic solvent and non-destructive. Moreover, the proposed conditions allowed the selective determination of MA in the presence of other primary and secondary short-chain aliphatic amines. The utility of the proposed procedure for the quantification of MA in different types of waters is discussed.
-
Liquid chromatographic determination of aliphatic amines in water using solid support assisted derivatization with 9-Fluorenylmethyl Chloroformate
Chromatographia, 2002Co-Authors: J Verdú-andrés, Pilar Campíns-falcó, Rosa Herráez-hernándezAbstract:A simple and sensitive method has been developed for the liquid chromatographic determination of short-chain aliphatic amines in water. Analytes are retained in solid-phase extraction (SPE) cartridges, and then derivatized by drawing an aliquot of the fluorogeneic reagent 9-Fluorenylmethyl Chloroformate (FMOC) through the cartridges. After a certain reaction time the derivatives formed are desorbed with acetonitrile. The collected extracts are then chromatographed on a LiChrospher 100 RP_18 125 mm×4 mm i.d., 5 μm, column using an acetonitrile-water gradient. The influence of experimental conditions (SPE material, volume of sample, concentration of FMOC, time of reaction and pH) has been investigated. Optimal results have been obtained with C_18 SPE cartridges using a sample volume of 5.0 mL. For derivatization, 0.25 mL aliquots of 25 mM FMOC have been used, the reaction time being only 2 min. The method has been applied to the quantification of several aliphatic amines: methylamine, ethylamine, dimethylamine, n -butylamine, n -pentylamine and n -hexylamine. Under the proposed conditions the percentages of analytes retained plus derivatized were of about 54–107% compared to those obtained with direct solution derivatization. The method provided good reproducibility, linearity and accuracy within the 0.050–1.0 mg L^−1 concentration range. The limits of detection were in the 0.25–5.0 μg L^−1 range. The utility of the described approach has been tested by analysing tap water, river water and industrial waste water.
-
Derivatization of tertiary amphetamines with 9-Fluorenylmethyl Chloroformate for liquid chromatography: determination of N-methylephedrine.
The Analyst, 2000Co-Authors: Rosa Herráez-hernández, Pilar Campíns-falcóAbstract:The fluorogenic reagent 9-Fluorenylmethyl Chloroformate (FMOC) was evaluated for the derivatization of tertiary amphetamines prior to liquid chromatographic analysis. Conditions for the derivatization were investigated, including the reaction time, the derivatization reagent concentration and the pH, using N-methylephedrine as a model compound. On the basis of these studies, a method for the quantification of N-methylephedrine is presented. The method involves derivatization with FMOC at ambient temperature and separation of the derivatives formed on a LiChrospher C18, 5 μm, 125 × 4 mm id column using acetonitrile–water gradient elution. The proposed procedure shows good linearity, accuracy and reproducibility in the 1.0–25.0 μg mL−1 concentration range. The limit of detection was 0.1 μg mL−1 and the limit of quantification was 0.5 μg mL−1. The utility of the assay was demonstrated by determining N-methylephedrine in water and urine samples.
Rosa Herráez-hernández - One of the best experts on this subject based on the ideXlab platform.
-
An evaluation of solid phase microextraction for aliphatic amines using derivatization with 9-Fluorenylmethyl Chloroformate and liquid chromatography.
Journal of chromatography. A, 2006Co-Authors: Rosa Herráez-hernández, C Cháfer-pericás, J Verdú-andrés, Pilar Campíns-falcóAbstract:The reliability of SPME combined with a chemical reaction for the analysis of short-chain aliphatic amines by liquid chromatography has been investigated. Different options to couple SPME and derivatization have been tested and compared: (i) derivatization of the analytes in solution followed by the extraction of the derivatives, (ii) extraction of the analytes and subsequent derivatization by immersing the SPME fibre onto a solution of the reagent, and (iii) extraction/derivatization of the analytes using fibres previously coated with the reagent. Methylamine (MA), dimethylamine (DMA) and trimethylamine (TMA) have been selected as a model of primary, secondary and tertiary amines, respectively. The analytes have been derivatized with the fluorogenic reagent 9-Fluorenylmethyl Chloroformate (FMOC), and the fibre coating was Carbowax-templated resin (CW-TR). The employment of fibres coated with FMOC to extract and derivatize the analytes was the best option, as compared with the other approaches tested the sensitivity was considerably improved. On the basis of these studies, a new procedure for the determination of MA, DMA and TMA in water is presented. To demonstrate the utility of the proposed conditions data on linearity, accuracy, repeatability and sensitivity are given. Results of the determination of the amines in tap, river and waste water are also presented.
-
A new selective method for dimethylamine in water analysis by liquid chromatography using solid-phase microextraction and two-stage derivatization with o-phthalaldialdehyde and 9-Fluorenylmethyl Chloroformate.
Talanta, 2005Co-Authors: Consuelo Cháfer-pericás, Rosa Herráez-hernández, Pilar Campíns-falcóAbstract:Abstract A new method is presented for the determination of DMA in water as its 9-Fluorenylmethyl Chloroformate (FMOC) derivative using solid-phase microextraction (SPME) and liquid chromatography. The method is based on the employment of SPME fibres coated with carbowax-templated resin (CW-TR) for analyte extraction and derivatization. The fibres were successively immersed in the samples, in a solution of o -phthalaldialdehyde and N -acethyl- l -cysteine (OPA–NAC) and finally, in a solution of FMOC. OPA–NAC reacted on the fibre with possible primary aliphatic amines present in the samples, particularly with PA which is a direct interferent in the determination of DMA with FMOC. In such a way, the formation of PA–FMOC during the second stage was prevented, and thus the method was selective for DMA. The proposed procedure was applied to the determination of DMA in the 1.0–10.0 μg/mL range. The method provided suitable linearity, accuracy and reproducibility, and limits of detection and quantification of 0.3 and 1.0 μg/mL, respectively. The applicability of the method for the determination of DMA in different types of water is shown.
-
Analysis of methylamine by solid-phase microextraction and HPLC after on-fibre derivatization with 9-Fluorenylmethyl Chloroformate
Analytica Chimica Acta, 2004Co-Authors: Rosa Herráez-hernández, Consuelo Cháfer-pericás, Pilar Campíns-falcóAbstract:Abstract A method for the determination of methylamine (MA) in aqueous matrices is reported which uses solid-phase microextraction (SPME) for enrichment and derivatization of the analyte, and high performance liquid chromatography (HPLC). The fluorogenic reagent 9-Fluorenylmethyl Chloroformate (FMOC) has been used for derivatization. The SPME fibres were successively immersed in the samples and in the derivatization solutions to extract MA and FMOC, respectively. After a defined time of reaction, the derivatized analyte was desorbed into the chromatographic system, and chromatographed in a LiChrosphere 100 RP18, 125 mm ×4 mm i.d., 5 μm, column under gradient elution. In order to improve the MA-FMOC peak profile, a precolumn ( 20 mm ×2.1 mm i.d., packed with Hypersil C18 phase, 30 μm) was connected on-line to the analytical column by means of a switching valve. The experimental conditions (including fibre coating, times of adsorption, reaction and desorption, and concentration of reagent) have been optimised, and the results have been compared with those achieved by using a method previously validated for aliphatic amines in which extraction and derivatization were carried into C18 solid-phase extraction (SPE) cartridges. Although less sensitive, the SPME based method allowed the quantification of MA over the range 2.5–10.0 μg/ml with linearity, reproducibility and accuracy comparable to that of the SPE based method, the limit of detection being 0.75 μg/ml. The main advantages of the proposed SPME procedure are: sample handling involved in the extraction and derivatization steps was considerably reduced, it was free organic solvent and non-destructive. Moreover, the proposed conditions allowed the selective determination of MA in the presence of other primary and secondary short-chain aliphatic amines. The utility of the proposed procedure for the quantification of MA in different types of waters is discussed.
-
Liquid chromatographic determination of aliphatic amines in water using solid support assisted derivatization with 9-Fluorenylmethyl Chloroformate
Chromatographia, 2002Co-Authors: J Verdú-andrés, Pilar Campíns-falcó, Rosa Herráez-hernándezAbstract:A simple and sensitive method has been developed for the liquid chromatographic determination of short-chain aliphatic amines in water. Analytes are retained in solid-phase extraction (SPE) cartridges, and then derivatized by drawing an aliquot of the fluorogeneic reagent 9-Fluorenylmethyl Chloroformate (FMOC) through the cartridges. After a certain reaction time the derivatives formed are desorbed with acetonitrile. The collected extracts are then chromatographed on a LiChrospher 100 RP_18 125 mm×4 mm i.d., 5 μm, column using an acetonitrile-water gradient. The influence of experimental conditions (SPE material, volume of sample, concentration of FMOC, time of reaction and pH) has been investigated. Optimal results have been obtained with C_18 SPE cartridges using a sample volume of 5.0 mL. For derivatization, 0.25 mL aliquots of 25 mM FMOC have been used, the reaction time being only 2 min. The method has been applied to the quantification of several aliphatic amines: methylamine, ethylamine, dimethylamine, n -butylamine, n -pentylamine and n -hexylamine. Under the proposed conditions the percentages of analytes retained plus derivatized were of about 54–107% compared to those obtained with direct solution derivatization. The method provided good reproducibility, linearity and accuracy within the 0.050–1.0 mg L^−1 concentration range. The limits of detection were in the 0.25–5.0 μg L^−1 range. The utility of the described approach has been tested by analysing tap water, river water and industrial waste water.
-
Derivatization of tertiary amphetamines with 9-Fluorenylmethyl Chloroformate for liquid chromatography: determination of N-methylephedrine.
The Analyst, 2000Co-Authors: Rosa Herráez-hernández, Pilar Campíns-falcóAbstract:The fluorogenic reagent 9-Fluorenylmethyl Chloroformate (FMOC) was evaluated for the derivatization of tertiary amphetamines prior to liquid chromatographic analysis. Conditions for the derivatization were investigated, including the reaction time, the derivatization reagent concentration and the pH, using N-methylephedrine as a model compound. On the basis of these studies, a method for the quantification of N-methylephedrine is presented. The method involves derivatization with FMOC at ambient temperature and separation of the derivatives formed on a LiChrospher C18, 5 μm, 125 × 4 mm id column using acetonitrile–water gradient elution. The proposed procedure shows good linearity, accuracy and reproducibility in the 1.0–25.0 μg mL−1 concentration range. The limit of detection was 0.1 μg mL−1 and the limit of quantification was 0.5 μg mL−1. The utility of the assay was demonstrated by determining N-methylephedrine in water and urine samples.
Gholamreza Bahrami - One of the best experts on this subject based on the ideXlab platform.
-
Determination of fatty acids by high-performance liquid chromatography and fluorescence detection using precolumn derivatization with 9-Fluorenylmethyl Chloroformate.
Journal of Liquid Chromatography & Related Technologies, 2016Co-Authors: Mohammad Bagher Majnooni, Bahareh Mohammadi, Ronak Jalili, Atefeh Babaei, Gholamreza BahramiAbstract:ABSTRACTA new high-performance liquid chromatographic method is described for the determination of fatty acids in seed oils. The method was based on precolumn derivatization with 9-Fluorenylmethyl Chloroformate as a labeling agent and fluorescence detection. Fatty acids were extracted from the samples and subjected to derivatization with the reagent at 60°C for 10 min. The chromatographic separation of 14 fatty acids (C10–C22) was achieved on a combined loading compression octadecyl sulfate (CLC-ODS) column with a run time of 30 min. Three-step gradient elution of a mobile phase consisted of acetonitrile and water was used, and the signal was monitored at excitation and emission wavelengths of 265 and 315 nm, respectively. The method indicated favorable sensitivity and reproducibility for fatty acids’ derivatives. The detection limits, at a signal-to-noise ratio of 3, were 0.01–0.05 µg/ml and relative standard deviations (RSDs) were less than 0.27%. Excellent linear responses were observed with coefficien...
-
9-Fluorenylmethyl Chloroformate as a fluorescence-labeling reagent for derivatization of carboxylic acid moiety of sodium valproate using liquid chromatography/tandem mass spectrometry for binding characterization: a human pharmacokinetic study.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2011Co-Authors: Bahareh Mohammadi, Mohammad Bagher Majnooni, Ronak Jalili, Pyman Malek Khatabi, Gholamreza BahramiAbstract:In High Performance Liquid Chromatographic (HPLC) determination of chemicals with acidic functions, different labeling agents are used to improve sensitivity of the assay. 9-Fluorenylmethyl Chloroformate (FMOC-Cl), on the other hand, is a suitable labeling agent, which reacts with both primary and secondary amines and less readily with hydroxyl groups in alkaline conditions. However, the reagent has not been applied in labeling of chemicals with acidic function yet. In this study which is the first report on application of FMOC-Cl in derivatization and analysis of a drug with acidic function, valproic acid (VPA), one of a series of fatty carboxylic acids with anticonvulsant activity, was derivatized using the reagent and quantified in serum samples by HPLC with fluorescence detection. In addition, to document the reaction between the labeling agent and carboxylic acid moiety of the drug, we developed a liquid chromatography-tandem MS/MS (LC-MS/MS) method. Following liquid-liquid extraction, derivatization of the drug and an internal standard was achieved in alkaline medium. The elute was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. The present method is more sensitive comparing with other published HPLC procedures for analysis of VPA. The assay is sensitive enough to measure drug levels obtained in human single dose studies with a limit of quantification of 0.01 μg/mL. Also the method is linear over the concentrations range of 0.01-32 μg/mL of VPA in human serum using 100 μL serum sample and 5 μL injection. The coefficient variation values of both inter and intra day analysis were less than 12% and the percentage error was less than 4%. The method performance was studied and the validated procedure applied in a randomized cross-over bioequivalence study of two different VPA preparations in 24 healthy volunteers.
-
Enhancement of Fluorescence Intensity of Tramadol and Its Main Metabolites in LC Using Pre-Column Derivatization with 9-Fluorenylmethyl Chloroformate
Chromatographia, 2008Co-Authors: Gholamreza Bahrami, Bahareh MohammadiAbstract:Tramadol was found to exhibit weak fluorescence with a maximum emission at 300 nm when excited at 200 nm. Also, fluorescence spectra of the drug and its two main metabolites, O -desmethyltramadol and N -desmethyltramadol are not practically identical. Thus low and different sensitivities have been reported for the drug and its metabolites in previously published work. In the present method using 9-Fluorenylmethyl Chloroformate (FMOC-Cl) as labeling agent, equal and magnified fluorescence intensity were obtained for the analytes. The drug, its metabolites and an internal standard (oseltamivir phosphate) were extracted from serum by dichloromethane. Pre-column derivatization of the analytes was achieved using FMOC-Cl in the presence of borate buffer (0.1 M, pH 7.5). Liquid chromatography with a mobile phase consisting of a mixture of 0.05 M phosphate buffer containing triethylamine (2 ml L^−1; pH = 3.0) and methanol (54:46; v/v ) and a Shimpack CLC-ODS column were used for analytical separation of the analytes. The fluorescence of the column effluent was monitored at an excitation and emission wavelengths of 265 and 315 nm, respectively. The analytical method was linear over the concentration range of 1.0–1,280 ng mL^−1 of the parent drug and its metabolites and limit of quantification of 1.0 ng mL^−1 was obtained for the analytes using 10 μL injection. The method validation was studied and the validated method applied in a bioequivalence study of 2 different tramadol preparations in 24 healthy volunteers.
-
Determination of clarithromycin in human serum by high-performance liquid chromatography after pre-column derivatization with 9-Fluorenylmethyl Chloroformate: application to a bioequivalence study.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2006Co-Authors: Gholamreza Bahrami, Bahareh MohammadiAbstract:A sensitive liquid chromatographic method for the analysis of clarithromycin, a macrolide antibiotic, in human serum using pre-column derivatization with 9-Fluorenylmethyl Chloroformate (FMOC-Cl) is described. The method involved liquid-liquid extraction of the drug and an internal standard (amantadine) followed by pre-column derivatization of the analytes with FMOC-Cl. A mixture of 0.05 M phosphate buffer containing triethylamine (2 mL L(-1); pH 3.8) and methanol (17:83, v/v) was used as mobile phase and chromatographic separation was achieved on a Shimpack CLC-ODS column. The eluate was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. The analytical method was linear over the concentration range of 0.025-10 microg mL(-1) of clarithromycin in human serum with a limit of quantification of 0.025 microg mL(-1). The assay is sensitive enough to measure drug levels obtained in human single dose studies. In the present method, sensitivity and run time of analysis have been improved, and successfully applied in a bioequivalence study of three different clarithromycin preparations in 12 healthy volunteers.
-
Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-Fluorenylmethyl Chloroformate.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2006Co-Authors: Gholamreza Bahrami, Amir KianiAbstract:Most of the published methods for analysis of gabapentin, an antiepileptic agent, in human serum are based on the same approach, involving o-phthaldialdehyde derivatization of deproteinized serum samples. The present paper however, describes a new, simple and sensitive high-performance liquid chromatographic method for determination of gabapentin in human serum using liquid-liquid extraction and 9-Fluorenylmethyl Chloroformate (FMOC-Cl) as pre-column labeling agent. The drug and an internal standard (azithromycin) were extracted from serum by salting-out approach using a mixture of dichloromethane-2 propanol (1:1, v/v) as the extracting solvent. The extracted analytes were subjected to derivatization with FMOC-Cl in the presence of phosphate buffer (pH 7). A mobile phase consisting of methanol-0.05 M sodium phosphate buffer (73/27, v/v; pH of 3.9) containing 1 ml/l triethylamine was eluted and chromatographic separation was performed on a Shimpack CLC-C18 (150 mm x 4.6 mm) column. The standard curve was linear over the range of 0.03-20 microg/ml and limit of quantification was 0.03 microg/ml. The performance of analysis was studied and the validated method showed excellent performance in terms of selectivity, specificity, sensitivity, precision and accuracy. No interferences were found from commonly co-administered antiepileptic agents.
Xianliang Zhou - One of the best experts on this subject based on the ideXlab platform.
-
Determination of Trace C1−C4 Aliphatic Alcohols in Aqueous Samples by 9-Fluorenylmethyl Chloroformate Derivatization and Reversed-Phase High-Performance Liquid Chromatography
Analytical chemistry, 1999Co-Authors: Gu Huang, Guohong Deng, Huancheng Qiao, Xianliang ZhouAbstract:A simple procedure for precolumn fluorescence derivatization of low-molecular-weight aliphatic alcohols (C1−C4) with 9-Fluorenylmethyl Chloroformate is presented. The derivatization reaction proceeds in 1:1 (v/v) aqueous−acetonitrile solution at room temperature with a sodium phosphate buffer of pH 12.5 as a catalyst. Stable fluorescent derivatives of the alcohols are formed within 10 min. The four derivatives are separated by reversed-phase high-performance liquid chromatography and detected by a fluorescence detector at an excitation wavelength of 259 nm and an emission wavelength of 311 nm. The method detection limits are 4, 40, 70, and 30 pmol for methanol, ethanol, propanol, and butanol, respectively, per 5-μL injection volume. The relative standard deviations are 3.7% for methanol at 75 pmol and 2.1, 1.5, and 2.2% for ethanol, propanol, and butanol, respectively, at 750 pmol. As a preliminary application, the method was used to determine methanol concentration in laboratory air and ethanol content i...
-
determination of trace c1 c4 aliphatic alcohols in aqueous samples by 9 Fluorenylmethyl Chloroformate derivatization and reversed phase high performance liquid chromatography
Analytical Chemistry, 1999Co-Authors: Gu Huang, Guohong Deng, Huancheng Qiao, Xianliang ZhouAbstract:A simple procedure for precolumn fluorescence derivatization of low-molecular-weight aliphatic alcohols (C1−C4) with 9-Fluorenylmethyl Chloroformate is presented. The derivatization reaction proceeds in 1:1 (v/v) aqueous−acetonitrile solution at room temperature with a sodium phosphate buffer of pH 12.5 as a catalyst. Stable fluorescent derivatives of the alcohols are formed within 10 min. The four derivatives are separated by reversed-phase high-performance liquid chromatography and detected by a fluorescence detector at an excitation wavelength of 259 nm and an emission wavelength of 311 nm. The method detection limits are 4, 40, 70, and 30 pmol for methanol, ethanol, propanol, and butanol, respectively, per 5-μL injection volume. The relative standard deviations are 3.7% for methanol at 75 pmol and 2.1, 1.5, and 2.2% for ethanol, propanol, and butanol, respectively, at 750 pmol. As a preliminary application, the method was used to determine methanol concentration in laboratory air and ethanol content i...
Ying Zhang - One of the best experts on this subject based on the ideXlab platform.
-
simultaneous analysis of n e carboxymethyl lysine and n e carboxyethyl lysine in foods by ultra performance liquid chromatography mass spectrometry with derivatization by 9 Fluorenylmethyl Chloroformate
Journal of Food Science, 2015Co-Authors: Yanqiong Zhou, Cheng Jin, Lu Cheng, Qin Lin, Xiaoyan Zheng, Ming Dai, Ying ZhangAbstract:Isotope dilution ultra-performance liquid chromatography-electrospray tandem mass spectrometry with derivatization by 9-Fluorenylmethyl Chloroformate was successfully applied to quantify N(e) -(carboxymethyl)lysine (CML) and N(e) -(carboxyethyl)lysine (CEL) in processed foods. We demonstrate that this analytical method is well validated for the determination of CML and CEL contents in processed foods. Relative standard deviations (RSD) indicate repeatability (RSD < 6% for CML and CEL) and reproducibility (RSD < 6% for CML and < 7% for CEL) in this method. Percent recovery is also good. We obtain recoveries of 102% to 112% for CML and 86% to 114% for CEL. CML levels detected in the samples vary from 2.29 to 480 mg/kg food, whereas CEL is detected in significantly lower concentrations ranging from 0.56 to 107 mg/kg food. These data could help consumers make better food choices by monitoring intake of advanced glycation end-products, which may pose a risk to human health.
-
Simultaneous analysis of N(ε) -(carboxymethyl)Lysine and N(ε) -(carboxyethyl)lysine in foods by ultra-performance liquid chromatography-mass spectrometry with derivatization by 9-Fluorenylmethyl Chloroformate.
Journal of food science, 2015Co-Authors: Yanqiong Zhou, Lin Qin, Cheng Jin, Lu Cheng, Zheng Xiaoyan, Dai Ming, Ying ZhangAbstract:Isotope dilution ultra-performance liquid chromatography-electrospray tandem mass spectrometry with derivatization by 9-Fluorenylmethyl Chloroformate was successfully applied to quantify N(e) -(carboxymethyl)lysine (CML) and N(e) -(carboxyethyl)lysine (CEL) in processed foods. We demonstrate that this analytical method is well validated for the determination of CML and CEL contents in processed foods. Relative standard deviations (RSD) indicate repeatability (RSD < 6% for CML and CEL) and reproducibility (RSD < 6% for CML and < 7% for CEL) in this method. Percent recovery is also good. We obtain recoveries of 102% to 112% for CML and 86% to 114% for CEL. CML levels detected in the samples vary from 2.29 to 480 mg/kg food, whereas CEL is detected in significantly lower concentrations ranging from 0.56 to 107 mg/kg food. These data could help consumers make better food choices by monitoring intake of advanced glycation end-products, which may pose a risk to human health.
