The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Mir Ali Farajzadeh - One of the best experts on this subject based on the ideXlab platform.
-
deep eutectic solvent based gas assisted dispersive liquid phase microextraction combined with gas chromatography and Flame Ionization Detection for the determination of some pesticide residues in fruit and vegetable samples
Journal of Separation Science, 2017Co-Authors: Mir Ali Farajzadeh, Masoumeh Sattari Dabbagh, Adeleh YadeghariAbstract:In this study, a gas-assisted dispersive liquid-phase microextraction method using a deep eutectic solvent as the extraction solvent combined with gas chromatography and Flame Ionization Detection was developed for the extraction and determination of some pesticide residues in vegetable and fruit juice samples. In this method, choline chloride and 4-chlorophenol at a molar ratio of 1:2 were mixed. By heating and vortexing, a clear, water-immiscible, and homogeneous liquid was formed. The obtained deep eutectic solvent was added to an aqueous solution of the analytes in a conical test tube. Air was bubbled into the aqueous solution and a cloudy solution was obtained. During this step, the analytes were extracted into the fine droplets of the extraction solvent. After centrifugation, an aliquot of the settled phase was injected into the separation system. Under the optimum extraction conditions, enrichment factors, and extraction recoveries were obtained in the ranges of 247–355 and 49–71%, respectively. The obtained values for the limits of Detection and quantification were in the ranges of 0.24–1.4 and 0.71–4.2 μg/L, respectively. The proposed method is simple, fast, efficient, and inexpensive.
-
extraction and preconcentration of residual solvents in pharmaceuticals using dynamic headspace liquid phase microextraction and their determination by gas chromatography Flame Ionization Detection
Biomedical Chromatography, 2017Co-Authors: Mir Ali Farajzadeh, Hamideh Dehghani, Adeleh Yadeghari, Leila KhoshmaramAbstract:The present study describes a microextraction and determination method for analyzing residual solvents in pharmaceutical products using dynamic headspace-liquid phase microextraction technique followed by gas chromatography-Flame Ionization Detection. In this method dimethyl sulfoxide (μL level) placed into a GC liner-shaped extraction vessel is used as a collection/extraction solvent. Then the liner is exposed to the headspace of a vial containing the sample solution. The effect of different parameters influencing the microextraction procedure including collection/extraction solvent type and its volume, ionic strength, extraction time, extraction temperature and concentration of NaOH solution used in dissolving the studied pharmaceuticals are investigated and optimized. Under the optimum extraction conditions, the method showed wide linear ranges between 0.5 and 5000 mg L-1 . The other analytical parameters were obtained in the following ranges: enrichment factors 240-327, extraction recoveries 72-98% and limits of Detection 0.1-0.8 mg L-1 in solution and 0.6-3.2 μg g-1 in solid. Relative standard deviations for the extraction of 100 mg L-1 of each analyte were obtained in the ranges of 4-7 and 5-8% for intra-day (n = 6) and inter-day (n = 4) respectively. Finally the target analytes were determined in different samples such as erythromycin, azithromycin, cefalexin, amoxicillin and co-amoxiclav by the proposed method.
-
application of elevated temperature dispersive liquid liquid microextraction for determination of organophosphorus pesticides residues in aqueous samples followed by gas chromatography Flame Ionization Detection
Food Chemistry, 2016Co-Authors: Mir Ali Farajzadeh, Mohammad Reza Afshar Mogaddam, Samaneh Rezaee Aghdam, Nina Nouri, Mahdi BamorrowatAbstract:Abstract In the present study, an elevated temperature, dispersive, liquid-liquid microextraction/gas chromatography-Flame Ionization Detection was investigated for the determination, pre-concentration, and extraction of six organophosphorus pesticides (malathion, phosalone, dichlorvos, diazinon, profenofos, and chlorpyrifos) residues in fruit juice and aqueous samples. A mixture of 1,2-dibromoethane (extraction solvent) and dimethyl sulfoxide (disperser solvent) was injected rapidly into the sample solution heated at an elevated temperature. Analytical parameters, including enrichment factors (1600–2075), linearity (r > 0.994), limits of Detection (0.82–2.72 ng mL −1 ) and quantification (2.60–7.36 ng mL −1 ), relative standard deviations ( −1 concentrations in apple juice.
-
development of continuous dispersive liquid liquid microextraction performed in home made device for extraction and preconcentration of aryloxyphenoxy propionate herbicides from aqueous samples followed by gas chromatography Flame Ionization detectio
Analytica Chimica Acta, 2016Co-Authors: Mir Ali Farajzadeh, Ali Mohebbi, Behruz FeriduniAbstract:In this study, a rapid, simple, and efficient sample preparation method based on continuous dispersive liquid-liquid microextraction has been developed for the extraction and preconcentration of aryloxyphenoxy-propionate herbicides from aqueous samples prior to their analysis by gas chromatography-Flame Ionization Detection. In this method, two parallel glass tubes with different diameters are connected with a teflon stopcock and used as an extraction device. A mixture of disperser and extraction solvents is transferred into one side (narrow tube) of the extraction device and an aqueous phase containing the analytes is filled into the other side (wide tube). Then the stopcock is opened and the mixture of disperser and extraction solvents mixes with the aqueous phase. By this action, the extraction solvent is dispersed continuously as fine droplets into the aqueous sample and the target analytes are extracted into the fine droplets of the extraction solvent. The fine droplets move up through the aqueous phase due to its low density compared to aqueous phase and collect on the surface of the aqueous phase as an organic layer. Finally an aliquot of the organic phase is removed and injected into the separation system for analysis. Several parameters that can affect extraction efficiency including type and volume of extraction and disperser solvents, sample pH, and ionic strength were investigated and optimized. Under the optimum extraction conditions, the extraction recoveries and enrichment factors ranged from 49 to 74% and 1633 to 2466, respectively. Relative standard deviations were in the ranges of 3-6% (n = 6, C = 30 μg L(-1)) for intra-day and 4-7% (n = 4, C = 30 μg L(-1)) for inter-day precisions. The limits of Detection were in the range of 0.20-0.86 μg L(-1). Finally the proposed method was successfully applied to determine the target herbicides in fruit juice and vegetable samples.
-
low density solvent based air assisted liquid liquid microextraction followed by gas chromatography with Flame Ionization Detection for the determination of synthetic phenolic antioxidants in milk samples
Journal of Separation Science, 2016Co-Authors: Mir Ali Farajzadeh, Mohammad Reza Afshar MogaddamAbstract:A simple and rapid sample pretreatment technique termed low-density-solvent-based air-assisted liquid-liquid microextraction has been developed for the extraction and preconcentration of three synthetic phenolic antioxidants including butylated hydroxyanisole, butylated hydroxytoluene, and tert-butyl hydroquinone from milk samples prior to their analysis by gas chromatography with Flame Ionization Detection. In this method, initially trichloroacetic acid as a proteins precipitation agent is added to the sample, and then it is sonicated and centrifuged. The obtained aqueous phase is removed and the analytes extracted by the proposed method using a low-density organic solvent. Some important parameters such as type and volume of extraction solvent, ionic strength, pH, and centrifugation rate and time were studied. Under the optimum conditions, enrichment factors were obtained in the range of 501-614. LODs and quantification were between 0.76-1.16 and 2.66-3.96 ng mL(-1) , respectively. This method is rapid and requires less than 15 min for sample preparation.
Mohammad Reza Afshar Mogaddam - One of the best experts on this subject based on the ideXlab platform.
-
application of elevated temperature dispersive liquid liquid microextraction for determination of organophosphorus pesticides residues in aqueous samples followed by gas chromatography Flame Ionization Detection
Food Chemistry, 2016Co-Authors: Mir Ali Farajzadeh, Mohammad Reza Afshar Mogaddam, Samaneh Rezaee Aghdam, Nina Nouri, Mahdi BamorrowatAbstract:Abstract In the present study, an elevated temperature, dispersive, liquid-liquid microextraction/gas chromatography-Flame Ionization Detection was investigated for the determination, pre-concentration, and extraction of six organophosphorus pesticides (malathion, phosalone, dichlorvos, diazinon, profenofos, and chlorpyrifos) residues in fruit juice and aqueous samples. A mixture of 1,2-dibromoethane (extraction solvent) and dimethyl sulfoxide (disperser solvent) was injected rapidly into the sample solution heated at an elevated temperature. Analytical parameters, including enrichment factors (1600–2075), linearity (r > 0.994), limits of Detection (0.82–2.72 ng mL −1 ) and quantification (2.60–7.36 ng mL −1 ), relative standard deviations ( −1 concentrations in apple juice.
-
low density solvent based air assisted liquid liquid microextraction followed by gas chromatography with Flame Ionization Detection for the determination of synthetic phenolic antioxidants in milk samples
Journal of Separation Science, 2016Co-Authors: Mir Ali Farajzadeh, Mohammad Reza Afshar MogaddamAbstract:A simple and rapid sample pretreatment technique termed low-density-solvent-based air-assisted liquid-liquid microextraction has been developed for the extraction and preconcentration of three synthetic phenolic antioxidants including butylated hydroxyanisole, butylated hydroxytoluene, and tert-butyl hydroquinone from milk samples prior to their analysis by gas chromatography with Flame Ionization Detection. In this method, initially trichloroacetic acid as a proteins precipitation agent is added to the sample, and then it is sonicated and centrifuged. The obtained aqueous phase is removed and the analytes extracted by the proposed method using a low-density organic solvent. Some important parameters such as type and volume of extraction solvent, ionic strength, pH, and centrifugation rate and time were studied. Under the optimum conditions, enrichment factors were obtained in the range of 501-614. LODs and quantification were between 0.76-1.16 and 2.66-3.96 ng mL(-1) , respectively. This method is rapid and requires less than 15 min for sample preparation.
-
determination of widely used non steroidal anti inflammatory drugs in biological fluids using simultaneous derivatization and air assisted liquid liquid microextraction followed by gas chromatography Flame Ionization Detection
Journal of The Iranian Chemical Society, 2016Co-Authors: Mir Ali Farajzadeh, Mohammad Reza Afshar Mogaddam, Hassan Nasrollahpour, Leila KhoshmaramAbstract:A sensitive and reliable method for the extraction, preconcentration, and determination of non-steroidal acidic anti-inflammatory drugs (ibuprofen, naproxen, and diclofenac) from biological samples has been developed using simultaneous derivatization and air-assisted liquid–liquid microextraction followed by gas chromatography–Flame Ionization Detection. In this method, a mixture of an extraction solvent (chloroform) and a derivatizing agent (butyl chloroformate) is added into a glass test tube containing an aqueous sample of the analytes and picoline (catalyst). The mixture is dispersed by repeatedly aspirating and dispensing via a syringe. By this action, derivatization and extraction of the selected analytes is performed simultaneously. Under the optimal conditions, enrichment factors and extraction recoveries were obtained in the ranges 364–412 and 72–82 %, respectively. The linear ranges were broad with correlation coefficients higher than 0.995. Limits of Detection were obtained in the ranges 0.06–3.30 and 0.24–13 ng mL−1 in urine and plasma samples, respectively. Limits of quantification were 0.21–9.2 ng mL−1 in urine and 0.84–37 ng mL−1 for plasma sample. Relative standard deviations were lower than 5.2 % for six repeated determinations at a concentration of 25 ng mL−1 of each analyte. Finally, the developed method was successfully applied to determine the selected analytes in urine and plasma samples.
-
determination of triazole pesticide residues in edible oils using air assisted liquid liquid microextraction followed by gas chromatography with Flame Ionization Detection
IEEE Journal of Solid-state Circuits, 2015Co-Authors: Mir Ali Farajzadeh, Behruz Feriduni, Mohammad Reza Afshar MogaddamAbstract:In the present study, a rapid, simple, and highly efficient sample preparation method based on air-assisted liquid–liquid microextraction followed by gas chromatography with Flame Ionization Detection was developed for the extraction, preconcentration, and determination of five triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole, and triticonazole) in edible oils. Initially, the oil samples were diluted with hexane and a few microliter of a less soluble organic solvent (extraction solvent) in hexane was added. To form fine and dispersed extraction solvent droplets, the mixture of oil sample solution and extraction solvent is repeatedly aspirated and dispersed with a syringe. Under the optimum extraction conditions, the method showed low limits of Detection and quantification between 2.2–6.1 and 7.3–20 μg/L, respectively. Enrichment factors and extraction recoveries were in the ranges of 71–96 and 71–96%, respectively. The relative standard deviations for the extraction of 100 and 250 μg/L of each pesticide were less than 5% for intraday (n = 6) and interday (n = 3) precisions. Finally edible oil samples were successfully analyzed using the proposed method, and hexaconazole was found in grape seed oil.
-
determination of some synthetic phenolic antioxidants and bisphenol a in honey using dispersive liquid liquid microextraction followed by gas chromatography Flame Ionization Detection
Food Analytical Methods, 2015Co-Authors: Mir Ali Farajzadeh, Mohammad Reza Afshar Mogaddam, Maryam Abbaspour, Houshang GhorbanpourAbstract:In the present study, an extraction, preconcentration, and determination method has been reported for some synthetic phenolic antioxidants and bisphenol A in honey samples using dispersive liquid–liquid microextraction technique followed by gas chromatography-Flame Ionization Detection. The main factors influencing the extraction efficiency including extractive solvent type and volume as well as the volume of dispersive solvent, salt addition, and pH are evaluated in this study. Under the optimum extraction conditions, limits of Detection and quantification for all target analytes were obtained in the ranges of 0.4–4.7 and 1.3–14 ng g−1, respectively. Enrichment factors and extraction recoveries were in the ranges of 144–186 and 72–93 %, respectively. The method precision was evaluated at 100 ng g−1 of each analyte, and the relative standard deviations were found to be less than 7.6 % for intra-day (n = 6) and less than 8.3 % for inter-days (n = 4). The proposed method has been successfully applied to the analysis of different honey samples and two analytes, butylated hydroxytoluene and butylated hydroxyanisole, were determined at nanogram per gram level in one honey sample.
Esmeralda Millan - One of the best experts on this subject based on the ideXlab platform.
-
optimization of headspace solid phase microextraction by means of an experimental design for the determination of methyl tert butyl ether in water by gas chromatography Flame Ionization Detection
Journal of Chromatography A, 2002Co-Authors: Julien Dron, R Garcia, Esmeralda MillanAbstract:Abstract A procedure for determination of methyl tert.-butyl ether (MTBE) in water by headspace solid-phase microextraction (HS-SPME) has been developed. The analysis was carried out by gas chromatography with Flame Ionization Detection. The extraction procedure, using a 65-μm poly(dimethylsiloxane)–divinylbenzene SPME fiber, was optimized following experimental design. A fractional factorial design for screening and a central composite design for optimizing the significant variables were applied. Extraction temperature and sodium chloride concentration were significant variables, and 20 °C and 300 g/l were, respectively chosen for the best extraction response. With these conditions, an extraction time of 5 min was sufficient to extract MTBE. The calibration linear range for MTBE was 5–500 μg/l and the Detection limit 0.45 μg/l. The relative standard deviation, for seven replicates of 250 μg/l MTBE in water, was 6.3%.
-
determination of butyltin species in water and sediment by solid phase microextraction gas chromatography Flame Ionization Detection
Journal of Chromatography A, 2000Co-Authors: Esmeralda Millan, Janusz PawliszynAbstract:Abstract A procedure for determination of tetraethyltin (TeET) and tetrabutyltin (TeBT) in water by solid-phase microextraction (SPME) using the headspace approach has been developed. The method has been adapted for the simultaneous determination of mono-, di- and tributyltin species (MBT, DBT and TBT) after derivatization with sodium tetraethylborate in water and sediment samples. The analytical procedures were optimized with respect to stirring conditions, extraction time and extraction temperature. The pH and the amount of derivatizing reagent were also considered in derivatization reaction procedures. The analysis was carried out using gas chromatography equipped with Flame Ionization Detection. The Detection limits obtained for TeET and TeBT, in equilibrium conditions (room temperature for TeET and 40°C for TeBT) were 28 and 20 ng/l (as Sn), respectively. The Detection limit for butyltin species in water, which was limited by signals which are non-specific for the tin compounds and the sensitivity of the FID system, was found ca. 1 μg/l (as Sn). The SPME method was validated for analysis of sediments by analyzing the certified reference material PACS-2 finding a good agreement with the certified values.
Felix Anyakudo - One of the best experts on this subject based on the ideXlab platform.
-
analysis of amikacin gentamicin and tobramycin by thin layer chromatography Flame Ionization Detection
Microchemical Journal, 2020Co-Authors: Felix Anyakudo, Erwin Adams, Ann Van SchepdaelAbstract:Abstract Amikacin, gentamicin and tobramycin are aminoglycoside antibiotics mostly used for the treatment of a wide range of aerobic Gram negative bacteria. Lack of a UV chromophore as well as their polar and non-volatile nature make direct determination of these aminoglycosides by conventional LC and GC very challenging. Existing analytical methodology is either expensive, complicated or time consuming. In this work, a thin layer chromatography – Flame Ionization method was developed for fast analysis of these aminoglycosides in pharmaceutical formulations. Paromomycin was used as internal standard for quantitation. Development of the rod with one single solvent mixture was sufficient to achieve the desired separation of target components. Good determination coefficients (>0.997) were achieved for all target analytes. Repeatability, recovery and Detection limits were determined and reported. A total of 5 samples in duplicate can be analyzed simultaneously within 25 s. This method offers the advantage of being able to analyze these aminoglycosides without any need for derivatization or laborious coloration. The developed method was applied to the analysis of some pharmaceutical commercial samples.
-
qualitative analysis of cetomacrogol creams by thin layer chromatography Flame Ionization Detection tlc fid
SN Applied Sciences, 2020Co-Authors: Lien Secretin, Felix Anyakudo, Liesbeth Gilissen, An Goossens, Ann Van SchepdaelAbstract:Buffered cetomacrogol cream has been described as the cause of iatrogenic allergic contact dermatitis, while patch testing with all ingredients was, in most cases, unable to identify the sensitizing culprit. Several hypotheses had been put forward, among which the formation of a new allergen by interaction of some of the ingredients, so-called ‘compound allergy’. In order to investigate this hypothesis, a method for the qualitative analysis of cetomacrogol creams, using thin-layer chromatography with Flame Ionization Detection (TLC–FID), is presented. All cetomacrogol cream components, i.e., a preservative and excipients were completely separated. A two-step elution system was used to separate the analytes on the Chromarods: in the first step we separated and focussed the paraffins and cetostearyl alcohol with the use of hexane-methanol–methyl tert-butyl ether (100:3:6, v/v). After drying, the same rod was then redeveloped using methanol to resolve sorbic acid from cetomacrogol 1000, whereupon Detection of the cream components could be performed by direct Flame Ionization Detection on the Chromarods. The developed method was then applied for the analysis of commercial non-buffered and buffered cetomacrogol cream samples. No newly formed allergen could be detected, thus excluding ‘compound allergy’. This method proved to be simple, cheap, and fast, enabling the separation of the auxiliary substances present in cetomacrogol cream.
-
thin layer chromatography Flame Ionization Detection
Chromatographia, 2020Co-Authors: Felix Anyakudo, Erwin Adams, Ann Van SchepdaelAbstract:Thin layer chromatography–Flame Ionization Detection (TLC–FID) is a versatile analytical technique that can be used for fast analysis of organic compounds. It has been implemented in past decades for the analysis of lipids and petrochemical products, but rarely in other fields. Despite the improvement in the latest Iatroscan model and the introduction of an automatic programmable sample spotter, this system is still struggling to gain acceptance in universities and major research laboratories. The reason behind this might be a lack of awareness on the potential application of this system to other fields of analytical chemistry. This review presents TLC–FID as a mature and reliable, state of the art technique that combines the separation power of TLC with FID as a universal detector, which can be applied to the analysis of a wide variety of organic compounds. Basic operational procedures and previous literature, including its potential for ultrafast analysis of commercial samples, are discussed in order to create awareness on the potentials of this piece of equipment to other fields.
Melissa A Francis - One of the best experts on this subject based on the ideXlab platform.
-
Flame Ionization Detection after splitting the water effluent in subcritical water chromatography
Journal of Chromatography A, 2002Co-Authors: Yu Yang, Aaryn D Jones, John Mathis, Melissa A FrancisAbstract:Abstract The coupling of subcritical water separation with Flame Ionization Detection (FID) in the split mode has been investigated in this study. In order to keep the FID system stable during subcritical water separation, a Tee union was connected between the separation column and the FID system to split the water flow. The ratio of the water flow to the FID system over the flow-rate to a waste bottle varied depending on the dimension of capillary tubings and the total water flow-rate used. Separations of several carbohydrates, carboxylic acids, and amino acids were performed on commercially available columns using a laboratory-made subcritical water chromatography–FID system. The FID system was very stable in this split mode even at total flow-rate as high as 1.24 ml/min. The linear dynamic range was up to three orders of magnitude and the limit of Detection (LOD) ranged from 38 to 111 ng (306–925 ng/μl injected) with split ratios of ∼1:10 to ∼1:17 (FID/waste bottle) for several analytes studied. However, the LOD can be significantly lowered by adjusting the dimensions of the restrictors to allow a higher percentage of the total flow to the FID system.