ANALYTICAL AND BIOANALYTICAL CHEMISTRY RESEARCH
Year:2018 | Volume:5 | Issue:2|Papers Count:17

For the first time, a novel and efficient ionic liquid-based ultrasound-assisted in situ solvent formation microextraction (IL-UA-ISFME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) has been successfully developed for the determination of duloxetine (DLX) in human plasma. Herein, an environmentally-friendly hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to sample solution including NaPF6 as an ion-pairing agent. The analyte was extracted into the ionic liquid although the microextraction solvent was dispersed among the sample solution using ultrasound radiation. The sample was then centrifuged and extracting phase injected into HPLC system. The developed sample enrichment method revealed a considerable robustness against the variations of sample ionic strength. Parameters controlling the performance of the microextraction were evaluated and optimized. The limit of detection was 0. 8 μ g l-1 while a good linearity (r2 = 0. 996) and a broad linear range (2. 0-1500 μ g l-1) were achieved. A reasonable relative recoveries (83. 6-92. 1%) and the appropriate intra-assay (4. 0-5. 1%, n = 5) and inter-assay (4. 3-7. 6%, n = 9) precisions along with an appropriate sample clean-up exhibited good performance of the analytical procedure. It was eventually validated for the screening purposes in human plasma after oral administration of the drug and some pharmacokinetic data were achieved. This green method is prompt, convenient, and reliable and offers satisfactory reproducibility as well as sufficient sensitivity.

In this work, a modified electrochemical sensor for the determination of amoxicillin (AMX) is introduced. A magnetic molecularly imprinted polymer (MMIP) was suspended in AMX solution and then collected on the surface of a magnetic carbon paste electrode (CPE) via a permanent magnet, situated within the carbon paste electrode, and then the voltammetry signals were recorded. It was confirmed that MMIP/CPE shows greater recognition ability than the magnetic non-molecularly imprinted (MNIP)/CPE. The influence of the operational parameters including pH, MMIP amount, extraction time and accumulation time was elucidated. The performance of the fabricated sensor was evaluated and the results indicated that the sensor has a high sensitivity in AMX detection, with a linear range from 0. 0010-0. 11 μ M and a limit of detection of 0. 26 nM. The MMIP/CPE is simple to fabricate and easy to use and was successfully applied to the determination of AMX in pharmaceutical samples with recoveries between 98. 8 and 103. 2%, without the need of a sample pre-treatment steps.

This research presents adsorption potential of surfactant (sodium dodecyl sulphate; SDS) coated magnetite nanoparticles as a suitable and efficient adsorbent for the removal of Basic Blue 41 (BB 41), a cationic dye from textile’ s company wastewater. The effects of various experimental parameters (e. g., initial pH of the solution, SDS amount, and ionic strength) on the adsorption efficiency of BB 41 were investigated and optimized. The result showed that kinetic of adsorption process is very fast, and equilibrium for dye adsorption could be obtained after 30 min. Equilibrium isotherm data were fitted to Langmuir and Freundlich models. The characteristic parameters for each model were also determined. The Langmuir isotherm gave the best correlation for the adsorption of BB 41 on the surface of adsorbent. A superior maximum adsorption capacity (2000. 6 mg g-1) was obtained for the adsorbent from the Langmuir model. Also, reuse study showed that Fe3O4 NPs could be regenerated and reused at least for six times.

In the present study, cucurbit[6]uril was used as a nonporous adsorbent for the removal of 2, 4-dinitrophenol from aqueous solutions. The experiments were carried out in a batch system to optimize operation variables such as pH of solution, contact time, adsorbent dose and salt concentration. Langmuir, Freundlich and Tempkin isotherms were applied for the explanation of experimental data. The high removal yield was achieved at the real pH, 0. 02 g of adsorbent dose and 10 min of contact time. The equilibrium adsorption was best described by the Langmuir isotherm model. The maximum monolayer adsorption capacity was found at 29. 85 mg g-1 for 2, 4-dinitrophenol at 25 ° C. The kinetics study showed that the adsorption process could be described by pseudo-second order rate equation, and equilibrium was achieved after 10 min. The thermodynamic parameters indicated that the adsorption of 2, 4-dinitrophenol on the cucurbit[6]uril is an endothermic and spontaneous process. The results of the present study confirm the applicability of small amount of this adsorbent for efficient removal of 2, 4-dinitrophenol from wastewater samples in short reasonable time.

In this study, a ZnO@Ag2O@Fe3O4 nanocomposite as an innovative magnetic solid phase extraction agent is introduced. The structural and morphological properties of the as-prepared nano-sorbent were characterized using X-ray diffraction analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and nitrogen adsorption– desorption techniques. The synthesized magnetic nano-sorbent was applied for extraction and pre-concentration of Cd(II) ions from water samples. The as-prepared nano-sorbent with the magnetism property was easily manipulated by a magnet. Factors affecting the extraction of the Cd(II) ions from aqueous solutions were investigated and optimized conditions were reported. Under optimum conditions, linear concentration range of 0. 1-10 ng ml-1 with a correlation coefficient of 0. 9918 was obtained for Cd(II) ions. The detection limit and enrichment factor for cadmium are 0. 03 ng ml-1 and 200, respectively. The intra-and inter-day relative standard deviations (at 4 ng ml-1 Cd(II) ion concentration and n = 6) were found to be 1. 8 and 2. 6%, respectively. The maximum sorption capacity of the nano-sorbent for cadmium was 48 mg g-1. The accuracy of the method was checked by the analysis of the standard reference material NIST SRM 1643e, and successfully applied to determine cadmium in several water and wastewater samples with relative recovery values in the range of 98-102% for the spiked samples.

The purpose of this study was to separate and determine Nystatin in water, urine and plasma samples using a method based on sodium dodecyl sulfate (SDS) coated magnetic nanoparticles (nano-magnets Fe3O4) along with spectrophotometry which has been developed for to this end. Due to their excellent adsorption capacity and high chemical stability, nanoparticles can be modified by surfactants. The extraction efficiency of Nystatin can be affected by different factors such as the amount of adsorbent, pH value, eluent type and its volume, extraction time, and ionic strength; these factors have been further studied and optimized. The method was successfully employed for extracting Nystatin from water, urine and plasma samples under optimized condition. The linear response of the method was over ranges of 1-20, 1-18 and 1-15 mg l-1 and the coefficients of determination were 0. 991, 0. 994 and 0. 991; these desirable coefficients were achieved for of water, urine and plasma samples, respectively. In addition, it was tried to investigate the relative recovery in different water, urine and plasma matrices and subsequently the values of 99%, 98% and 102% were obtained. It could be concluded that the method employed here was conveniently fast, linear, efficient and economical for extracting Nystatin in water and biological samples.

Monitoring the acetaminophen in biological samples and also in pharmaceutical formulations is important due to the concerns of public health care and drug safety. In this work a carbon paste electrode modified with BaTiO3 nanoparticle (BTO NPs) and room-temperature ionic liquid (IL) (n-hexyl-3-methylimidazolium hexafluoro phosphate) was fabricated. The direct electro-oxidation behavior of acetaminophen (AC) was carefully studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA) and the diffusion coefficient, D of acetaminophen at the BTOILCPE surface was estimated. The results exhibited a remarkable increase in the electron transfer rate and significant decrease in the overpotential for acetaminophen oxidation reaction in contrast to that on the bare carbon paste electrode (CPE). Under the optimal conditions using DPV, the oxidation peak current was linear to the acetaminophen concentration over the range of 1. 0-600. 0 μ M with a detection limit of 0. 46 μ M. The proposed sensor was successfully applied in pharmaceutical and urine samples with satisfactory results.

Manganese plays a key role in the health of human beings, therefore, its determination is very important in medical fields. In this regard, for the first time, a novel coated graphite electrode was constructed for determination of manganese(II) by using zolpidem as an ionophore. The best performance was obtained for the membrane composition of PVC (32%), potassium tetrakis (4-chlorophenyl) borate (3%) as ionic additive, zolpidem (10%) as ionophore and dioctyl phthalate (55%) as plasticizer. The linear working range of the potentiometric sensor was from 1 × 10-7-1 × 10-2 M. The electrode shows an exquisite Nernstian slope value of 29. 7 mV Decade-1 and its limit of detection was 9 × 10-8 M. The potential response of the membrane sensor was also evaluated in non aqueous mediums, and it was found out that the electrode can also be used in systems containing 15% of ethanol and acetone organic solvents. The selectivity was also inspected through matching potential method for 20 different cations, and the electrode demonstrated a significant selectivity toward Mn2+ for all of the studied cations. In the end, the applicability of the electrode in the determination of Mn2+ in dietary supplements, as real samples, was investigated.

Here, a simple, quick and sensitive potentiometric method is described for tramadol hydrochloride measurement using PVC membrane electrode based on neutral ligand (E)-N'-(1-(2-hydroxyphenyl)ethylidene)benzohydrazid. Besides, effect of various parameters like ionic additives, membrane solvent and pH on the potentiometric response of the electrode are investigated. The best electrode performance was observed with membrane composition of PVC 30%, DBP 60%, carrier 7% and additive 3% within pH range of 3-6. This electrode showed Nernstian slope about-60. 24 ± 0. 2 mV dec-1, detection limit of 1. 75 × 10-6 M and response time about 15 s over the concentration range of 1. 0 × 10-1-3. 16 × 10-6 M. The lifetime of electrode was about 40 days. Finally, to evaluate the performance of the electrode, the amount of tramadol hydrochloride were measured in three samples, including urine, cow's milk and tablet. The results showed that the mentioned electrode has the more appropriate performance compared to the other usual approaches.

In this study, fatty acid (FA) composition of aerial parts of selected Salvia species from Iran was analyzed by gas chromatography. The amount of FAs was quantified for leaf and shoot of species as mg per kg (mg kg-1) of dry weight. The results showed that FA contents of aerial parts for the studied plants vary significantly between 73. 05 and 739. 50 mg kg-1 of dried weight. Caprylic (C8: 0, 1. 00-380. 49 mg kg-1), elaididc (C18: 1n9t, 0. 73-97. 29 mg kg-1), stearic (C18: 0, 1. 1-62. 97 mg kg-1), palmitic (C16: 0, 1. 19-36. 48 mg kg-1), and α-linoleic (C18: 3n3, 1. 34-19. 36 mg kg-1) acid were main FAs identified. The numerical analysis was performed on FA composition of shoot and leaf of specimens and the shoot FA composition was selected to identify the systematic position of studied species. The UPGMA (Unweighted Pair Group Method with Arithmetic Mean) dendrogram showed that the species are classified into two clusters. Caprylic acid (C8: 0), behenic acid (C22: 0), and lignoceric acid (C24: 0) were chief characters in the infrageneric grouping the species in the genus. S. chloroleuca and S. atropatana were placed in cluster I and separated from other species based on shoot FA composition. The discrimination of Salvia species based on their botanical classification was supported by results. The results confirmed that FA composition of shoot are distinguishable and can be used as chemotaxonomic markers.

In this study, ultrasonic-assisted matrix solid-phase dispersion (UA-MSPD) as a new sample preparation method for natural product analysis was developed. Influential parameters of the UA-MSPD method were optimized using oleuropein content of olive leaves as a model analyte. Main parameters of the proposed technique such as ultrasonic time, ultrasonic amplitude and pulse, sorbent material, the ratio of sample to sorbent material, elution solvent and its volume have been fully evaluated and optimized. In the proposed method several steps in classical MSPD including transfer of sample and sorbent mixture to cartridge, packing and elution under vacuum conditions were removed. Also, ultrasound waves were applied to the sample and sorbent mixture in elution step for effective analyte desorption. Oleuropein was successfully extracted by silica gel and acetone as the sorbent and elution solvent, respectively. The calibration curve shows good linearity (R2 = 0. 9979) and precision (RSD < 6. 8) in the concentration range of 0. 1-200 μ g ml-1 for oleuropein. The limit of detection (LOD) and limit of quantitation (LOQ) were 0. 03 and 0. 1 μ g ml-1, respectively. The recovery values were in the range of 90. 2-96. 7% with RSD values ranging from 5. 5-7. 2%.

The metal ions constituents of plants is reliable for determination of their medicinal, nutritional and toxicity properties. A novel, simple and accurate spectrophotometric method was developed for the simultaneous determination of Ag+, Cu2+ and Ni2+ ions in different medicinal plants without prior separation steps. This method was based on the different kinetic characteristics between the reactions of analytes with newly synthesized Schiff base as dimethyl 2, 2’ ,-(ethan-1, 2-diylbis1)bis(cyclopent-1-ene-1-carbodithioate(DEBC). All experimental conditions, including DEBC concentration, and the effects of pH and temperature were optimized. Also, orthogonal array design was applied for the construction of concentration. The differential kinetic spectra were monitored and recorded at 397 nm. The reaction orders were estimated with respect to complex mixture of analytes with DEBC. Limit of detection values were 0. 013, 0. 078 and 0. 003 mg l-1 and limit of quantification values were 0. 043, 0. 250 and 0. 011 for, Cu2+, Ni2+ and Ag+, respectively. The recorded data were processed by principal component analysis-back propagation neural networks (PCBPNNs). A set of synthetic mixtures of metal ions was evaluated and the obtained results by PCBPNNs were discussed. The simultaneous analysis was also performed without compressed data and was compared with those obtained by PCBPNNs. The proposed method was successfully applied to the simultaneous determination of metal ions in medicinal plant samples. The results of the proposed method were compared by those obtained on the same samples using Graphite furnace atomic absorption spectrometry.

A simple, accurate and fast vortex-assisted dispersive liquid-liquid microextraction procedure has been developed for the extractive spectrophotometric determination of niflumic acid in biological samples. The method is based on the formation of an ion association complex between niflumic acid and methylene blue. The resulting ion-pair was extracted into dichloromethane and its absorbance was measured at 655 nm. All experimental parameters affecting the analytical performance of the method such as pH, type and volume of buffer and extraction solvent, dye concentration, extraction time, ionic strength and interfering species were investigated. The calibration curve was linear in the range of 5-70 ng ml-1 and the limit of detection (LOD) was found to be 2. 8 ng ml-1. The procedure was successfully applied for the determination of niflumic acid in human plasma and goat’ s milk samples. The main advantages of the proposed method are rapidity, little solvent consumption, low cost and providing low LOD by the simple UV-Vis spectrophotometer.

In this work, for the first time, poly (benzoquinone) chromium(III) complex (PBQC) was synthesized with a one pot, one step, simple and fast method. This novel polymer was used for modification of graphite paste electrode for electrochemical determination of Mesalazine. Moreover, this novel modifier was characterized by Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, and electrochemistry methods such as cyclic voltammetry and differential pulse voltammetry. Various parameters affecting the electroanalytical application of this modified electrode were optimized. Under the optimum condition, the calibration curve was linear in a wide range from 2-600 μ M with a detection limit (S/N = 3) of 70 nM. The proposed modified electrode is a good candidate for the determination of Mesalazine with satisfactory results in comparison with the other literature. Moreover, the proposed modified electrode, GPE/PBQC, was successfully used for determination of Mesalazine in pharmaceutical tablets.

In this study, a label-free electrochemical immunosensor for ultrasensitive detection of Hepatitis C virus core antigen in serum samples was fabricated using a simple approach. In this method, a low-cost and sensitive immunosensor was fabricated based on a boehmite nanoparticles (BNPs) modified glassy carbon. The BNPs provide a specific platform with an increased surface area which is capable of loading more antibody molecules as a receptor element of Hepatitis C virus core antigen on the electrode surface. It seems that BNP/ antibody conjugate may be an ideal platform for the development of an efficient immunosensor. It is worth noting that the proposed nanoimmunosensor combines the advantages of the elimination of another substrates in modifying the electrode and reducing the length of the modifying process. The experimental parameters, such as pH and incubation of time were optimized. Under the optimal conditions for modified glassy carbon electrode, a linear relationship was realized in the range of 0. 08-110 pg ml-1, with the detection limit of 10 fg ml-1. The proposed method was applied to the determination of Hepatitis C virus core antigen in serum samples with the desirable results.

In the present study, magnetic core-shell manganese ferrite nanoparticles (MCMNP) were synthesized and used for construction of a magnetic core-shell manganese ferrite nanoparticles modified screen-printed carbon electrode (MCSNP-SPCE). Cyclic voltammetry was used to study the electrochemical behavior of chlorpromazine (CPZ) and its determination was conducted by applying square wave voltammetry (SWV). The MCSNP-SPCE in comparison with bare SPCE exhibited enhanced electrocatalytic activity toward the oxidation of CPZ. A single irreversible oxidation peak was observed at a potential of 500 mV and 630 mV on the MCSNP-SPCE and bare SPCE, respectively. Under the optimized conditions, the anodic peak current of CPZ recorded by SWV varies linearly with CPZ concentration in the range 0. 25-60 μ M with a detection limit of 0. 08 μ M. The MCSNP-SPCE was used for quantitative analysis of CPZ in tablet and urine samples and the results indicate the feasibility of the amperometric method for CPZ analysis in routine detection.

Green synthesis of metal nanoparticles is an interesting issue of nanoscience due to its simplicity and eco-friendliness. The present study describes a cheaper, non-toxic and simple route for biosynthesis of Silver nanoparticles using Phlomis cancellata Bunge extracts. Since the experimental conditions of this procedure play vital roles in the synthesis rate of the nanoparticles, a response surface methodology using the central composite design was employed for testing the reaction variables. The individual and interactive effects of process variables (temperature, time, concentration of AgNO3 and pH) on the production rate of AgNPs were monitored and the optimal reaction conditions for the maximum production were found at the reaction temperature of 77. 62 ° C, duration of 24. 79 min, pH of 6. 84 and concentration of 4. 76 mM of AgNO3. AgNPs were characterized by advanced techniques like UV-Vis spectroscopy (UV-Vis), infrared spectroscopy (IR), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). The weight composition of Ag synthesized by Phlomis cancellata Bunge leaf extracts is higher than those normally found in other sources highlighting its industrial application. However, the use of Phlomis cancellata leaves can add value to a non-usable waste.