Maryam Rajabi

Simplified miniaturized ultrasound-assisted matrix solid phase dispersion extraction and high performance liquid chromatographic determination of seven flavonoids in citrus fruit juice and human fluid samples: Hesperetin and naringenin as biomarkers

In the present study, for the first time, a simplified miniaturized ultrasound-assisted matrix solid-phase dispersion (SM-USA-MSPD) method with a different application for liquid matrices was developed to extract different flavonoids (hesperidin, diosmin, eriocitrin, narirutin, naringin, hesperetin and naringenin) from citrus fruit juice and human fluid samples prior to their determination using high performance liquid chromatography (HPLC). Different effective parameters were studied and under the optimum conditions (including sample volume: 150μL; solid phase: silica-based C18, 200mg; eluting solvent: methanol, 500μL; pH: 4; and sonication: 6min; at room temperature), limits of detection and limits of quantification were ranged from 23.3 to 46.8ngmL(-1) and 74.8 to 141.5ngmL(-1), respectively. Once optimized, analytical performance of the method was studied in terms of linearity (0.074-198.5μgmL(-1), r(2)>0.991), accuracy (recovery=84.6-101.5%), and precision (repeatability: intra-day precision<5.9%, and inter-day precision<7.2%). At the end, SM-USA-MSPD method was successfully applied to estimate the levels of hesperetin and naringenin in plasma and urinary excretion -after ingestion of orange, grapefruit and lime juices- and the obtained results confirmed that these compounds could be used as good biomarkers of citrus fruit juice intake.

Preparation and characterization of an AC–Fe3O4–Au hybrid for the simultaneous removal of Cd2+, Pb2+, Cr3+ and Ni2+ ions from aqueous solution via complexation with 2-((2,4-dichloro-benzylidene)-amino)-benzenethiol: Taguchi optimization

Activated carbon (AC) was magnetized with Fe3O4 nanoparticles (AC–Fe3O4-NPs) and loaded with Au nanoparticles (AC–Fe3O4–Au-NPs), and was fully characterized using different techniques such as XRD, XPS, VSM, TEM and SEM. 2-((2,4-Dichloro-benzylidene)-amino)-benzenethiol (DBABT), a complexing agent, was synthesized and characterized using 1H-NMR, ES-MS and FT-IR analysis. Subsequently, AC–Fe3O4-NPs was modified with DBABT and applied for the ultrasound-assisted removal of Cd2+, Pb2+, Cr3+ and Ni2+ ions via complexation with DBABT. The influences of variables such as reaction time and adsorbent mass (equilibrium) were optimized simultaneously. The method under optimum conditions was set at pH 5, concentrations of 5, 15, 25 and 25 mg L−1 for the Cd2+, Pb2+, Cr3+ and Ni2+ ions, respectively, 0.02 g for the adsorbent mass, 5 min sonication time and 6 mg L−1 for the concentration of DBABT, producing removal percentages of 80.59, 93.85, 68.52 and 81.68 for Cd2+, Pb2+, Cr3+ and Ni2+ ions, respectively. Analysis of real experimental equilibrium data at various concentrations of analytes reveals the efficiency of the Langmuir model for good representation of experimental data, with maximum mono-layer adsorption capacities of 185.22, 135.14, 188.70 and 133.34 mg g−1 for Cd2+, Pb2+, Cr3+ and Ni2+ ions respectively. The experimental data at various real times reveal that in most situations the systems reach equilibrium at contact times lower than 20 min, while the data fitted well to a combination of a pseudo second order kinetic model and intraparticle diffusion.

Tandem dispersive liquid-liquid microextraction as an efficient method for determination of basic drugs in complicated matrices.

A simple and efficient approach is introduced for the improvement of the clean-up and applicability of the dispersive liquid-liquid microextraction (DLLME) method in complicated matrices. For this purpose, two dispersive microextraction methods were combined, and the tandem dispersive liquid-liquid microextraction (TDLLME) method was provided. At first, using the ultrasound-assisted emulsification microextraction (USAEME) method, the tricyclic anti-depressant (TCA) drugs nortriptyline, imipramine, and amitriptyline, as the model compounds, contained in an aqueous sample solution (8.0 mL), were extracted into an organic solvent (35 μL). Then by utilizing the air-agitated liquid-liquid microextraction (AALLME) method, these analytes were simply back-extracted into 50 μL of an aqueous acceptor phase. By performing this convenient extraction method, a high sample clean-up was obtained; the overall extraction time was 7 min. The back-extraction step could be performed in less than 2 min, and very simple tools were required for this purpose. The response surface methodology (RSM) was used for the optimization of the experimental parameters so that the volumes 95 and 50 μL were obtained for the organic solvent and the acceptor phase, respectively, and the pH values of 11.25 and 1.75 were obtained for the donor and acceptor phases, respectively, as the optimal extraction conditions. Under the optimized conditions, TDLLME-HPLC-UV provided a good linearity in the range of 2.5-5000 ng mL(-1), low limits of detection (0.7-1.0 ng mL(-1)), good extraction repeatabilities (relative standard deviations below 6.2%, n=5), and enrichment factors (EFs) of 50-101. Finally, the developed method was successfully used for the determination of the mentioned drugs in the wastewater and human plasma samples.

Comparison of ultrasound-enhanced air-assisted liquid-liquid microextraction and low-density solvent-based dispersive liquid-liquid microextraction methods for determination of nonsteroidal anti-inflammatory drugs in human urine samples.

Two dispersive-based liquid-liquid microextraction methods including ultrasound-enhanced air-assisted liquid-liquid microextraction (USE-AALLME) and low-density solvent-based dispersive liquid-liquid microextraction (LDS-DLLME) were compared for the extraction of salicylic acid (the hydrolysis product of acetylsalicylic acid), diclofenac and ibuprofen, as instances of the most commonly used nonsteroidal anti-inflammatory drugs (NSAIDs), in human urine prior to their determination by gas chromatography with flame ionization detection (GC-FID). The influence of different parameters affecting the USE-AALLME (including type and volume of the extraction solvent, sample pH, ionic strength, and simultaneous sonication and number of extraction cycles) and the LDS-DLLME (including type and volume of the extraction and disperser solvents, sample pH, and ionic strength) were investigated to optimize their extraction efficiencies. Both methods are fast, simple and convenient with organic solvent consumption at μL level. However, the best results were obtained using the USE-AALLME method, applying 30 μL of 1-octanol as extraction solvent, 5.0 mL of sample at pH 3.0, without salt addition, and 5 extraction cycles during 20s of sonication. This method was validated based on linearities (r(2) >0 .971), limits of detection (0.1-1.0 μg L(-1)), linear dynamic ranges (0.4-1000.0 μg L(-1)), enrichment factors (115 ± 3-135 ± 3), consumptive indices (0.043-0.037), inter- and intra-day precisions (4.3-4.8 and 5.6-6.1, respectively), and relative recoveries (94-103%). The USE-AALLME in combination with GC-FID, and with no need to derivatization step, was demonstrated to be a simple, inexpensive, sensitive and efficient method to determine NSAIDs in human urine samples.

Optimized syringe-assisted dispersive micro solid phase extraction coupled with microsampling flame atomic absorption spectrometry for the simple and fast determination of potentially toxic metals in fruit juice and bio-fluid samples

In this work, a novel method called Syringe-assisted dispersive micro solid phase extraction (SA-DM-SPE) was developed based on repeatedly withdrawing and pushing out a mixture of an aqueous sample including some chelated potentially toxic metal ions with bis-(acetylacetone) ethylenediimine and a low level of a suitable adsorbent (1.6 mg of multi-walled carbon nanotubes) in a test tube using a syringe. Since maximum contact surface areas were simply provided between the chelated ions and adsorbent with no need to essentially off-line the accelerating mass transfer (including sonication and vortex) and centrifugation steps, maximum efficiency was achieved within a short period of time. The optimized conditions for the extraction of Pb2+, Cd2+, Co2+, Ni2+, and Cr3+, as target ions, were investigated by the experimental design strategy. Under the optimum conditions, limits of detection, linear dynamic ranges, consumptive indices, and repeatabilities (in terms of intra-day precisions) ranged from 0.3 to 2.0 μg L−1, 0.9 to 980 μg L−1, ∼0.33, and 3.4 to 4.2, respectively. The method was successfully applied to the determination of target ions in different water (tap and wastewater), fruit juice (apple, pear, grape, and grapefruit), and biological fluid (saliva and urine) samples using a microsampling flame atomic absorption spectrometry (MS-FAAS) technique.

Organic solvent-free air-assisted liquid-liquid microextraction for optimized extraction of illegal azo-based dyes and their main metabolite from spices, cosmetics and human bio-fluid samples in one step.

Air-assisted liquid-liquid microextraction (AALLME) has unique capabilities to develop as an organic solvent-free and one-step microextraction method, applying ionic-liquids as extraction solvent and avoiding centrifugation step. Herein, a novel and simple eco-friendly method, termed one-step air-assisted liquid-liquid microextraction (OS-AALLME), was developed to extract some illegal azo-based dyes (including Sudan I to IV, and Orange G) from food and cosmetic products. A series of experiments were investigated to achieve the most favorable conditions (including extraction solvent: 77μL of 1-Hexyl-3-methylimidazolium hexafluorophosphate; sample pH 6.3, without salt addition; and extraction cycles: 25 during 100s of sonication) using a central composite design strategy. Under these conditions, limits of detection, linear dynamic ranges, enrichment factors and consumptive indices were in the range of 3.9-84.8ngmL(-1), 0.013-3.1μgmL(-1), 33-39, and 0.13-0.15, respectively. The results showed that -as well as its simplicity, fastness, and use of no hazardous disperser and extraction solvents- OS-AALLME is an enough sensitive and efficient method for the extraction of these dyes from complex matrices. After optimization and validation, OS-AALLME was applied to estimate the concentration of 1-amino-2-naphthol in human bio-fluids as a main reductive metabolite of selected dyes. Levels of 1-amino-2-naphthol in plasma and urinary excretion suggested that this compound may be used as a new potential biomarker of these dyes in human body.

In-tube electro-membrane extraction with a sub-microliter organic solvent consumption as an efficient technique for synthetic food dyes determination in foodstuff samples.

A simple and efficient extraction technique with a sub-microliter organic solvent consumption termed as in-tube electro-membrane extraction (IEME) is introduced. This method is based upon the electro-kinetic migration of ionized compounds by the application of an electrical potential difference. For this purpose, a thin polypropylene (PP) sheet placed inside a tube acts as a support for the membrane solvent, and 30μL of an aqueous acceptor solution is separated by this solvent from 1.2mL of an aqueous donor solution. This method yielded high extraction recoveries (63-81%), and the consumption of the organic solvent used was only 0.5μL. By performing this method, the purification is high, and the utilization of the organic solvent, used as a mediator, is very simple and repeatable. The proposed method was evaluated by extraction of four synthetic food dyes (Amaranth, Ponceau 4R, Allura Red, and Carmoisine) as the model analytes. Optimization of variables affecting the method was carried out in order to achieve the best extraction efficiency. These variables were the type of membrane solvent, applied extraction voltage, extraction time, pH range, and concentration of salt added. Under the optimized conditions, IEME-HPLC-UV provided a good linearity in the range of 1.00-800ngmL(-1), low limits of detection (0.3-1ngmL(-1)), and good extraction repeatabilities (RSDs below 5.2%, n=5). It seems that this design is a proper one for the automation of the method. Also the consumption of the organic solvent in a sub-microliter scale, and its simplicity, high efficiency, and high purification can help one getting closer to the objectives of the green chemistry.

In-line micro-matrix solid-phase dispersion extraction for simultaneous separation and extraction of Sudan dyes in different spices.

A novel, simple, fast, and miniaturized method, termed in-line micro-matrix solid-phase dispersion (in-line MMSPD), coupled with high performance liquid chromatography (HPLC) was developed for the simultaneous extraction and determination of Sudan dyes (i.e. Sudan I-IV, Sudan orange G, Sudan black B, and Sudan red G) with the aid of an experimental design strategy. In this method, a matrix solid-phase dispersion (MSPD) column including a suitable mixture of polar sorbents was inserted in the mobile phase pathway, and while the interfering compounds were retained, the analytes were eluted and entered into the analytical column. In this way, the extraction, elution, and separation of the analytes were performed sequentially. Under the optimal experimental conditions (including the amount of sample, 0.0426g; amount of dispersant phase, 0.0216g of florisil, 0.0227g of silica, 0.0141g of alumina; and blending time, 112s), the limits of detection (LODs), limits of quantification, linear dynamic ranges, and recoveries were obtained to be 0.3-15.3μgkg(-1), 1-50μgkg(-1), 50-28,000μgkg(-1), and 94.5-99.1%, respectively. The results obtained showed that determination of the selected Sudan dyes in food samples using an enough sensitive and a simple analytically validated method like in-line MMSPD may offer a suitable screening method, which could be useful for food analysis and adulteration.

Comparison of air‐agitated liquid–liquid microextraction and ultrasound‐assisted emulsification microextraction for polycyclic aromatic hydrocarbons determination in hookah water

In this work, two disperser-free microextraction methods, namely, air-agitated liquid-liquid microextraction and ultrasound-assisted emulsification microextraction are compared for the determination of a number of polycyclic aromatic hydrocarbons in aqueous samples, followed by gas chromatography with flame ionization detection. The effects of various experimental parameters upon the extraction efficiencies of both methods are investigated. Under the optimal conditions, the enrichment factors and limits of detection were found to be in the ranges of 327-773 and 0.015-0.05 ng/mL for air-agitated liquid-liquid microextraction and 406-670 and 0.015-0.05 ng/mL for ultrasound-assisted emulsification microextraction, respectively. The linear dynamic ranges and extraction recoveries were obtained to be in the range of 0.05-120 ng/mL (R(2) ≥ 0.995) and 33-77% for air-agitated liquid-liquid microextraction and 0.05-110 ng/mL (R(2) ≥ 0.994) and 41-67% for ultrasound-assisted emulsification microextraction, respectively. To investigate this common view among some people that smoking hookah is healthy due to the passage of smoke through the hookah water, samples of both the hookah water and hookah smoke were analyzed.

Simultaneous extraction and preconcentration of some metal ions using eucalyptus-wood based activated carbon modified with silver hydroxide nanoparticles and a chelating agent: optimization by an experimental design

In the present work, the solid phase extraction (SPE) of Cr(III), Cu(II), Pb(II), Ni(II), Cd(II), and Co(II) metal ions was carried out using a new adsorbent, activated carbon modified with silver hydroxide nanoparticles and a chelating agent. The activated carbon was produced by the acid treatment of the carbon obtained from eucalyptus wood. The effects of different parameters on the metal ion preconcentrations were studied and optimized by a central composite experimental design, which is one of the most applicable response surface methodologies used in the design of experiments. The four major variables affecting the adsorption process, consisting of the pH value, amount of adsorbent, amount of ligand, and flow rate of the sample solution, were optimized. In the desorption process, the volume, concentration, and flow rate of the eluting solvent were considered as the variables affecting the amount of metal ion preconcentration. At the end of each step, the metal ions were quantified by flame atomic absorption spectrometry (FAAS). Under the optimal conditions, the recovery percentage and enrichment factor for all the metal ions under study were higher than 98% and 100, respectively (except for the Ni(II) ion, with an enrichment factor of 83.6), which indicate the high performance of the presented preconcentration method. Also, the detection limits for the Cr(III), Cu(II), Pb(II), Ni(II), Cd(II), and Co(II) ions were found to be 4.7, 3, 4, 1.7, 1.6, and 2.3 μg L−1, respectively. The relative standard deviation values for six replicate measurements of 0.2 mg L−1 of each metal ion were lower than 2.62%. Thus this preconcentration method can have a high accuracy and precision in the determination of trace amounts of potentially toxic metal ions.