Column preconcentration and faas determination of heavy metal ions using Artemisia Siberi as an adsorbent.

A new column procedure for the determination of trace amounts of cadmium (II), lead (II), nickel (II), zinc (II), and copper (II), which combines flame atomic absorption spectrometry is described. These metals were sorbed on Artemisia siberi herb as an adsorbent at pH 4.0 and eluted with 3 mL of 1.5 M HNO3. The influences of analytical parameters including pH, flow rate, sample volume, type of eluent, and effect of diverse salts and cations on the recoveries of analyte ions were studied. The developed procedure provides preconcentration factors of about 117. LODs were 0.2 (Cd), 0.4 (Cu), 0.2 (Ni), 0.6 (Zn), and 1.4 (Pb) µg/L. The present method was successfully applied to the determination of the above-mentioned ions in water samples from Semnan, Iran. Recoveries greater than 95% and RSDs below 10% were obtained.

Synthesis of molecularly imprinted polymer as a nanosorbent for dispersive magnetic micro solid-phase extraction and determination of valsartan in biological samples by UV-Vis Spectrophotometry: Isotherm, kinetics, and thermodynamic studies.

A magnetic molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization utilizing Fe3O4@SiO2-MPS as a magnetic core, itaconic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross linker. It was then applied as a nanosorbent for dispersive magnetic micro solid phase extraction (DM-µ-SPE) and determination of valsartan in biological fluids. The morphology and structure of magnetic MIP were characterized by Fourier-transform infrared spectroscopy, Field Emission Scanning electron microscopy, Vibrating sample magnetometer, Energy dispersive x-ray analysis, and Thermogravimetric analysis. The influence of operation conditions on sorption, such as pH (4-10), contact time (10-25 min), initial concentration (1-30 mg L-1), and temperature (25-40 °C) was investigated. After the extraction step, the valsartan concentration was determined by UV-Vis spectrophotometer at 253 nm. The isotherm and kinetic of valsartan sorption were best fitted by the Langmuir model (R2 = 0.987) and the Pseudo second-order kinetic model (R2 = 0.971), respectively. The maximum monolayer sorption capacity for magnetic MIP was obtained to be 4.56 mg g-1. The analytical approach demonstrated favorable figures of merit, with a linear dynamic range of 10-100 µg L-1, a low detection limit of 0.56 µg L-1, and an acceptable preconcentration factor of 5 acquired in optimum conditions. The recoveries of the suggested technique at three spiked levels of analysis were in the range of 101 %-102 %. Valsartan was extracted from various real samples (urine and human blood plasma samples) utilizing the proposed magnetic nanosorbent, and the results exhibited that magnetic MIP was favorable for extraction and measurement of trace amounts of valsartan in biological samples.

Co-delivery of doxorubicin and conferone by novel pH-responsive ß-cyclodextrin grafted micelles triggers apoptosis of metastatic human breast cancer cells.

Adjuvant-aided combination chemotherapy is one of the most effective ways of cancer treatment by overcoming the multidrug resistance (MDR) and reducing the side-effects of anticancer drugs. In this study, Conferone (Conf) was used as an adjuvant in combination with Doxorubicin (Dox) for inducing apoptosis to MDA-MB-231 cells. Herein, the novel biodegradable amphiphilic ß-cyclodextrin grafted poly maleate-co-PLGA was synthesized by thiol-ene addition and ring-opening process. Micelles obtained from the novel copolymer showed exceptional properties such as small size of around 34.5 nm, CMC of 0.1 µg/mL, and cell internalization of around 100% at 30 min. These novel engineered micelles were used for combination delivery of doxorubicin-conferone with high encapsulation efficiency of near 100% for both drugs. Our results show that combination delivery of Dox and Conf to MDA-MB-231 cells had synergistic effects (CI < 1). According to cell cycle and Annexin-V apoptosis analysis, Dox-Conf loaded micelle significantly induce tumor cell apoptosis (more than 98% of cells population showed apoptosis at IC50 = 0.259 µg/mL). RT-PCR and western-blot tests show that Dox-Conf loaded ßCD-g-PMA-co-PLGA micelle induced apoptosis via intrinsic pathway. Therefore, the unique design of multi-functional pH-sensitive micelles open a new perspective for the development of nanomedicine for combination chemo-adjuvant therapy against malignant cancer.

Novel ion imprinted polymer electrochemical sensor for the selective detection of lead(II).

The application of a novel Pb2+ selective sensor based on the ionic imprinted polymer in determining trace levels of lead in natural water and in fruit juice was investigated using differential pulse voltammetry (DPV). The new and selective magnetic ion-imprinted polymer (Fe3O4@SiO2@IIP) was synthesized using 2-(2-aminophenyl)-1H-benzimidazole and 4-vinyl pyridine as a ligand and functional monomer, respectively. The new polymer was utilized for modifying a GCE to generate a new electrochemical sensor. Box-Behnken design (BBD) was utilized for optimizing the parameters influencing the peak current. Extremely suitable voltammetric performance was demonstrated for the electrochemical detection of lead with a low detection limit (0.05 ng mL-1), over a wide linear concentration range (0.1-80 ng mL-1). This modified electrode as a novel sensor was utilized for determining Pb(II) ions in natural water and in fruit juice with very reasonable outcomes.

A novel magnetic ion imprinted polymer as a selective magnetic solid phase for separation of trace lead(II) ions from agricultural products, and optimization using a Box-Behnken design.

In this work, a magnetic ion-imprinted polymer (Fe3O4@SiO2@IIP) as a novel and selective nanosorbent for selective extraction of Pb(II) ions from various agricultural products is presented. The novel lead magnetic ion-imprinted polymer was synthesized by imidazole as a new ligand and grafted onto the surface of Fe3O4@SiO2 NPs. A Box-Behnken (BBD) design was used for optimization of the extraction and elution steps. In the selected conditions, the limit of detection was 0.48ngmL-1, preconcentration factor was 300, the sorption capacity of this new magnetic ion-imprinted polymer was 105mgg-1, and the precision of the method (RSD%) for six replicate measurements was found 3.2%. Finally, the feasibility of the new magnetic ion-imprinted polymer was evaluated by extraction and determination of trace Pb2+ ions in different agricultural products including (orange, mango, apple, kiwi, lettuce, broccoli, carrot, squash, eggplant, radish, mushroom, cucumber, and tomato).

Stirring-controlled solidified floating solid-liquid drop microextraction as a new solid phase-enhanced liquid-phase microextraction method by exploiting magnetic carbon nanotube-nickel hybrid.

A specific technique is introduced to overcome limitations of classical solidification of floating organic drop microextraction, such as tedious and time-consuming centrifuge step and using disperser solvent, by facile and efficient participation of solid and liquid phases. In this proposed method of stirring-controlled solidified floating solid-liquid drop microextraction (SC-SF-SLDME), magnetic carbon nanotube-nickel hybrid (MNi-CNT) as a solid part of the extractors are dispersed ultrasonically in sample solution, and the procedure followed by dispersion of liquid phase (1-undecanol) through high-rate stirring and easily recollection of MNi-CNT in organic solvent droplets through hydrophobic force. With the reduction in speed of stirring, one solid-liquid drop is formed on top of the solution. MNi-CNT acts as both extractor and the coalescence helper between organic droplets for a facile recollection. MNi-CNT was prepared by spray pyrolysis of nickel oleate/toluene mixture at 1000 °C. Four tyrosine kinase inhibitors were selected as model analytes and the effecting parameters were investigated. The results confirmed that magnetic nanoadsorbent has an important role in the procedure and complete collection of dispersed solvent is not achieved in the absence of the solid phase. Also, short extraction time exhibited success of the proposed method and effect of dispersed solid/liquid phases. The limits of quantification (LOQs) for imatinib, sunitinib, erlotinib, and nilotinib were determined to be as low as 0.7, 1.7, 0.6, and 1.0 µg L-1, respectively. The intra-day precisions (RSDs) were lower than 4.5%. Method performance was investigated by determination of mentioned tyrosine kinase inhibitors (TKIs) in human serum and cerebrospinal fluid samples with good recoveries in the range of 93-98%.

Graphene-silica hybrid in efficient preconcentration of heavy metal ions via novel single-step method of moderate centrifugation-assisted dispersive micro solid phase extraction.

Novel nanoadsorbent of graphene-silica hybrid was synthesized via chemical vapor deposition (CVD) method. Graphene sheets were catalytically grown on a silica-based substrate and after being characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), their high efficacy in adsorption of metal ions (lead, cadmium, and chromium) was examined. It was found that the presence of silica within the G-SiO2 structure imparts an amphiphilic property to the hybrid that enables it to interact with both free and bounded metal ions present in the biological samples. Utilization of the innovative method of moderate centrifugation-assisted dispersive micro solid phase extraction (MCDµSPE) coupled with electrothermal atomic absorption spectrometry (ETAAS), not only facilitated absolute separation of the fabricated nanoadsorbent from the solvent, but also helped complete recovering of the scant volume of desorbed supernatant. Thus, microliter amount of desorption solvent can be regained completely by MCDµSPE method without sorbent loss. Various parameters affecting the extraction efficiency were investigated and admirable linearity from 0.012 to 12.5 µg L(-1) and favorable detection limits (LOD) could be recorded. Intra day precision (RSD, n=10) ranged from 3.1 to 3.8%, whereas inter day precision (RSD, n=5) ranged from 6.3 to 7.2%.

Innovative separation and preconcentration technique of coagulating homogenous dispersive micro solid phase extraction exploiting graphene oxide nanosheets.

A uniquely novel, fast, and facile technique is introduced for the first time in which a scant amount of graphene oxide (GO), without modification, has been utilized in dispersive mode of solid phase extraction (SPE) for an efficient yet simple separation. The proposed method of coagulating homogenous dispersive micro solid phase extraction (CHD-µSPE) is based on coagulation of homogeneous GO solution with the aid of polyetheneimine (PEI). CHD-µSPE use full adsorption capacity of GO because in this method was used GO solution obtained from synthesis process without drying step and stacking nanosheets. In optimized condition, 30 µL GO solution (7 mg mL(-1)), obtained in synthesis process, was injected into 1.5 mL the sample solution followed by immediate injection of 53 µL PEI solution (1 mg mL(-1)). After inserting PEI, GO sheets aggregate and can be readily separated by centrifugation. PEI not only cause aggregation of GO, but also form three-dimensional network of GO with easy handling in following separation steps. Lead, cadmium, and chromium were selected as model analytes and the effecting parameters including the amount of GO, concentration of PEI, sample pH, extraction time, and type of desorption solvent were investigated and optimized. The results indicate that the proposed CHD-µSPE method can be successfully applied GO in dispersive mode of SPE without effecting on good capability adsorption of GO. The novel method was applied in determination of lead, cadmium, and chromium in water, human saliva, and urine samples by electrothermal atomic absorption spectrometry. The detection limits are as low as 0.035, 0.005, and 0.012 µg L(-1) for Pb, Cd, and Cr respectively. The intra-day precisions (RSDs) were lower than 3.8%. CHD-µSPE method showed a good linear ranges of 0.24-15.6, 0.015-0.95 and 0.039-2.33 µg L(-1) for Pb, Cd and Cr respectively. Method performance was investigated by determination of mentioned metal ions in river water, human urine and saliva sample with good recoveries in range of 94.2-103.0%. The accuracy of the method was underpinned by correct analysis of a standard reference material (SRM: 2668 level I, Urine).