scholarly journals Cobalt Ferrite Nanocomposite as Electrochemical Sensor for The Detection of Guanine, Uric Acid and Their Mixture

2021 ◽  
Vol 15 (4) ◽  
pp. 520-525
Author(s):  
Yogendra Kumar ◽  
◽  
Vivek Sharma ◽  
Vinod Kumar Vashistha ◽  
Rajasekhar VSR Pullabhotla ◽  
...  
Keyword(s):  
Uric Acid ◽  
Electrochemical Sensor ◽  
Crystallite Size ◽  
Lower Limit ◽  
Cobalt Ferrite ◽  
Limit Of Detection ◽  
Analytical Techniques ◽  
Average Crystallite Size ◽  
Cubic Structure

Cobalt ferrite nanocomposite was synthesized and characterized by analytical techniques such as FESEM, EDS and XRD. The average crystallite size was found to be in the range of 10–12 nm with a cubic structure. Further, the nanocomposite was used for the detection of guanine (GU) and uric acid (UA) and found to be an efficient electrode modifier. The lower limit of detection for GU and UA was found to be 300 nM and 400 nM, respectively

scholarly journals Boost the Crystal Installation and Magnetic Features of Cobalt Ferrite/M-Type Strontium Ferrite Nanocomposites Double Substituted by La3+ and Sm3+ Ions (2CoFe2O4/SrFe12−2xSmxLaxO19)

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7820
Author(s):  
Mahmoud M. Hessien ◽  
Ali Omar Turky ◽  
Abdullah K. Alanazi ◽  
Mohammed Alsawat ◽  
Mohamed H. H. Mahmoud ◽  
...  
Keyword(s):  
Saturation Magnetization ◽  
Crystallite Size ◽  
Cobalt Ferrite ◽  
Average Crystallite Size ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
Ion Substitution ◽  
Double Substitution ◽  
Lanthanum Cobalt Oxide ◽  
Co Doped

Spinel cobalt ferrite/hexagonal strontium hexaferrite (2CoFe2O4/SrFe12−2xSmxLaxO19; x = 0.2, 0.5, 1.0, 1.5) nanocomposites were fabricated using the tartaric acid precursor pathway, and the effects of La3+–Sm3+ double substitution on the formation, structure, and magnetic properties of CoFe2O4/SrFe12−2xSmxLaxO19 nanocomposite at different annealing temperatures were assayed through X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. A pure 2CoFe2O4/SrFe12O19 nanocomposite was obtained from the tartrate precursor complex annealed at 1100 °C for 2 h. The substitution of Fe3+ ion by Sm3–+La3+ions promoted the formation of pure 2CoFe2O4/SrFe12O19 nanocomposite at 1100 °C. The positions and intensities of the strongest peaks of hexagonal ferrite changed after Sm3+–La3+ substitution at ≤1100 °C. In addition, samples with an Sm3+–La3+ ratio of ≥1.0 annealed at 1200 °C for 2 h showed diffraction peaks for lanthanum cobalt oxide (La3Co3O8; dominant phase) and samarium ferrite (SmFeO3). The crystallite size range at all constituent phases was in the nanocrystalline range, from 39.4 nm to 122.4 nm. The average crystallite size of SrFe12O19 phase increased with the number of Sm3+–La3+ substitutions, whereas that of CoFe2O4 phase decreased with an x of up to 0.5. La–Sm co-doped ion substitution increased the saturation magnetization (Ms) value and the subrogated ratio to 0.2, and the Ms value decreased with the increasing number of double substitutions. A high saturation magnetization value (Ms = 69.6 emu/g) was obtained using a La3+–Sm3+ co-doped ratio of 0.2 at 1200 for 2 h, and a high coercive force value (Hc = 1192.0 Oe) was acquired using the same ratio at 1000 °C.

Preparation of A Magnetic Nanosensor Based on Cobalt Ferrite Nanoparticles for The Electrochemical Determination of Methyldopa in The Presence of Uric Acid

2020 ◽  
Vol 23 (10) ◽  
pp. 1023-1031
Author(s):  
Khadijeh Najafi ◽  
Karim Asadpour-Zeynali ◽  
Fariba Mollarasouli
Keyword(s):  
Uric Acid ◽  
Electrochemical Sensor ◽  
Cobalt Ferrite ◽  
Electrochemical Determination ◽  
Ferrite Nanoparticles ◽  
Current Response ◽  
Experimental Conditions ◽  
X Ray ◽  
Cobalt Ferrite Nanoparticles

Aim and Objective: Methyldopa is one of the medications that is used for the treatment of hypertension. Therefore, the determination of methyldopa in the presence of other biological components is essential. In this work, a promising electrochemical sensor based on CoFe2O4 magnetic nanoparticles modified glassy carbon electrode (CoFe2O4/GCE) was developed for electrochemical determination of methyldopa in the presence of uric acid. Cobalt ferrite nanoparticles were synthesized via chemical method. Materials and Methods: Characterizing the CoFe2O4 was investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), and cyclic voltammetry techniques. Results: Under the optimal experimental conditions, the current response of the electrochemical sensor obtained with differential pulse voltammetry was increased linearly in the concentration range from 1.45 to 15.1 μmol L−1 with the detection limit of 1.07 μmol L−1 for methyldopa. Also, by using the proposed method, methyldopa and uric acid could be analyzed in a mixture independently. The difference in peak potential for analytes is about 150 mV. Conclusion: The present sensor was successfully applied for the determination of methyldopa in the presence of uric acid in biological samples and the pharmaceutical samples with satisfactory results.

scholarly journals Consciousness Energy Healing Treatment: Impact on Physicochemical and Thermal Properties of Silver Sulfadiazine

2018 ◽  
Vol 2 (1) ◽  
pp. 1-13
Author(s):  
Nayak Nayak ◽  
Mahendra Kumar Trivedi ◽  
Alice Branton ◽  
Dahryn Trivedi ◽  
Snehasis Jana
Keyword(s):  
Thermal Properties ◽  
Crystallite Size ◽  
Latent Heat ◽  
Control Sample ◽  
Analytical Techniques ◽  
Average Crystallite Size ◽  
Silver Sulfadiazine ◽  
Heat Of Fusion ◽  
Treated Sample ◽  
Energy Healing

Silver sulfadiazine is a topical medicine that belongs to sulfa antibiotics class of drugs and used in treating wound infections in burn patients. The aim of this study was to determine the effect of Consciousness Energy Healing Treatment (the Trivedi Effect®) on the various properties of silver sulfadiazine with the help of modern analytical techniques. The sample was divided into two parts; the first part was not given any treatment and considered as a control sample, while the second part was provided the Consciousness Energy Healing Treatment by the Biofield Energy Healer, Gopal Nayak remotely, named as the treated sample. The powder XRD data showed significant alterations in the peak intensities of the treated sample ranging from-30.71% to 47.54% compared to the control sample. The crystallite size was altered ranging from -78.12% to 1.47%; and the average crystallite size was significantly reduced by 31.62% in the treated sample compared to the control sample. The particle sizes were decreased in the treated sample by 12.75%(d10), 4.98%(d50), 0.89%(d90), and 2.92%{D(4,3)}; thus, the specific surface area was significantly increased by 17.31% compared with the control sample. The latent heat of fusion and latent heat of decomposition were profoundly increased by 24.62% and 156.28%, respectively in the treated sample compared to the control sample. The total weight loss was increased by 3.08% and the residue amount was reduced by 4.44% in the treated sample compared to the control sample. Thus, the Trivedi Effect®-Consciousness Energy Healing Treated sample might form a new polymorph of silver sulfadiazine that possesses reduced particle size and improved thermal properties compared to the untreated sample. Therefore, the Biofield Energy treated sample can be used in nutraceutical/pharmaceutical formulation, which would show a better bioavailability and therapeutic response against various infections in comparison to the control sample.

scholarly journals The Structural and Magnetic Properties of Gadolinium Doped CoFe2O4Nanoferrites

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Qing Lin ◽  
Jinpei Lin ◽  
Yun He ◽  
Ruijun Wang ◽  
Jianghui Dong
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Crystallite Size ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Structural And Magnetic Properties

Gadolinium substituted cobalt ferrite CoGdxFe2−xO4(x= 0, 0.04, 0.08) powders have been prepared by a sol-gel autocombustion method. XRD results indicate the production of a single cubic phase of ferrites. The lattice parameter increases and the average crystallite size decreases with the substitution of Gd3+ions. SEM shows that the ferrite powers are nanoparticles. Room temperature Mössbauer spectra of CoGdxFe22−xO4are two normal Zeeman-split sextets, which display ferrimagnetic behavior. The saturation magnetization decreases and the coercivity increases by the Gd3+ions.

scholarly journals Iron-Doped Titanium Dioxide Nanoparticles As Potential Scaffold for Hydrazine Chemical Sensor Applications

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 182 ◽  
Author(s):  
Ahmad Umar ◽  
Farid A. Harraz ◽  
Ahmed A. Ibrahim ◽  
Tubia Almas ◽  
Rajesh Kumar ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Tio2 Nanoparticles ◽  
High Performance ◽  
Chemical Sensor ◽  
Limit Of Detection ◽  
Titanium Dioxide Nanoparticles ◽  
Average Crystallite Size ◽  
Average Diameter ◽  
Structural Morphology ◽  
Doped Tio2

Herein, we report the fabrication of a modified glassy carbon electrode (GCE) with high-performance hydrazine sensor based on Fe-doped TiO2 nanoparticles prepared via a facile and low-cost hydrothermal method. The structural morphology, crystalline, crystallite size, vibrational and scattering properties were examined through different characterization techniques, including FESEM, XRD, FTIR, UV–Vis, Raman and photoluminescence spectroscopy. FESEM analysis revealed the high-density synthesis of Fe-doped TiO2 nanoparticles with the average diameter of 25 ± 5 nm. The average crystallite size of the synthesized nanoparticles was found to be around 14 nm. As-fabricated hydrazine chemical sensors exhibited 1.44 μA µM−1 cm−2 and 0.236 µM sensitivity and limit of detection (LOD), respectively. Linear dynamic ranged from 0.2 to 30 µM concentrations. Furthermore, the Fe-doped TiO2 modified GCE showed a negligible inference behavior towards ascorbic acid, uric acid, glucose, SO42−, NO3−, Pb2+ and Ca2+ ions on the hydrazine sensing performance. Thus, Fe-doped TiO2 modified GCE can be efficiently used as an economical, easy to fabricate and selective sensing of hydrazine and its derivatives.

Skin exposure: requirements to methods determining active ingredient of pesticides in washings

2019 ◽  
pp. 43-48
Author(s):  
V. N. Rakitskii ◽  
N. E. Fedorova ◽  
I. V. Bereznyak ◽  
N. G. Zavolokina ◽  
L. P. Muhina
Keyword(s):  
Lower Limit ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Absorbed Dose ◽  
Ambient Air ◽  
Safety Coefficient ◽  
Limit Value ◽  
Calculated Risk ◽  
Nature Studies ◽  
Active Substances

The article presents results of studies exemplified by diquat on analysis concerning influence of lower limit value of quantitative assessment in washing sample for safety coefficient in exposure and in absorbed dose, if acting substance is absent in workplace ambient air samples and in dermal washings of workers. To control diquat in dermal washings, there is a method based on ion-pair liquid chromatography with ultraviolet detection (working wavelength 310 nm). To concentrate sample, cartridges for solid-phase extraction, containing ion exchange sorbent (Oasis MCX 6cc/500 mg), are used. Lower limit of assessment in washing sample — 0,15 micrograms. Experimentally set washing completeness is within range of 80–92%, standard deviation of repetition is 7,0% at most. The method created was tested in nature studies determining dermal exposure in workers subjected to 5 various preparations based on diquat dibromide when used for surface spraying from tractor and from aircraft. For lower limit of detection in washing sample (0,15 micrograms/washing), calculated risk value of exposure varied within 0,26–0,36; risk of absorbed dose was low — 0,23 (the allowable one ≤1). Findings are that present measuring methods which provide lower limit of detection 1 and 5 micrograms in washing sample could result in unallowable risk establishment even with absence of the substance in all samples of workplace air and dermal washings. The calculation formula suggested enables to give theoretic basis for requirements to lower limit of detecting active substances in dermal washing samples for evaluating risk of pesticides use in agriculture.

Eco-Friendly Green Liquid Chromatographic Separations of a Novel Combination of Azelastine and Fluticasone in the Presence of their Pharmaceutical Dosage form Additives

2020 ◽  
Vol 16 (3) ◽  
pp. 277-286
Author(s):  
Amal A. El-Masry ◽  
Mohammed E. A. Hammouda ◽  
Dalia R. El-Wasseef ◽  
Saadia M. El-Ashry
Keyword(s):  
Lower Limit ◽  
Dosage Form ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Uv Detection ◽  
Simultaneous Estimation ◽  
Limit Of Quantification ◽  
Chromatographic Separations ◽  
Pharmaceutical Dosage Form ◽  
Liquid Chromatographic

Background: The first highly sensitive, rapid and specific green microemulsion liquid chromatographic (MELC) method was established for the simultaneous estimation of fluticasone propionate (FLU) and azelastine HCl (AZL) in the presence of their pharmaceutical dosage form additives (phenylethyl alcohol (PEA) and benzalkonium chloride (BNZ)). Methods: The separation was performed on a C18 column using (o/w) microemulsion as a mobile phase which contains 0.2 M sodium dodecyl sulphate (SDS) as surfactant, 10% butanol as cosurfactant, 1% n-octanol as internal phase and 0.3% triethylamine (TEA) adjusted at pH 6 by 0.02 M phosphoric acid; with UV detection at 220 nm and programmed with flow rate of 1 mL/min. Results: The validation characteristics e.g. linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), accuracy, precision, robustness and specificity were investigated. The proposed method showed linearity over the concentration range of (0.5-25 µg/mL) and (0.1-25 µg/mL) for FLU and AZL, respectively. Besides that, the method was adopted in a short chromatographic run with satisfactory resolution factors of (2.39, 3.78 and 6.74 between PEA/FLU, FLU/AZL and AZL/BNZ), respectively. The performed method was efficiently applied to pharmaceutical nasal spray with (mean recoveries ± SD) (99.80 ± 0.97) and (100.26 ± 0.96) for FLU and AZL, respectively. Conclusion: The suggested method was based on simultaneous determination of FLU and AZL in the presence of PEA and BNZ in pure form, laboratory synthetic mixture and its combined pharmaceutical dosage form using green MELC technique with UV detection. The proposed method appeared to be superior to the reported ones of being more sensitive and specific, as well as the separation was achieved with good performance in a relatively short analysis time (less than 7.5 min). Highly acceptable values of LOD and % RSD make this method superior to be used in quality control laboratories with of HPLC technique.

scholarly journals Graphite Studded with Facile-Synthesized Cu2O Nanoparticle-Based Cubes as a Novel Electrochemical Sensor for Highly Sensitive Voltametric Determination of Mebeverine Hydrochloride

Chemosensors ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 35
Author(s):  
Ahmed H. Naggar ◽  
Ahmed Kotb ◽  
Ahmed A. Gahlan ◽  
Mahmoud H. Mahross ◽  
Abd El-Aziz Y. El-Sayed ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Lower Limit ◽  
Electrochemical Behavior ◽  
Cuprous Oxide ◽  
Density Functional ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Chemical Reduction ◽  
Anodic Stripping Voltammetry ◽  
Mebeverine Hydrochloride

Herein, a feasible chemical reduction method followed by intensive mixing was applied for the preparation of an attractive material based on graphite studded with cuprous oxide nanoparticle-based cubes (Cu2ONPs–C@G). Transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV) were utilized for characterization. Cuprous oxide nanoparticles (Cu2ONPs), with a diameter range mainly distributed from 4 to 20 nm, aggregate to form microcubes (Cu2ONPs–C) with an average diameter of about 367 nm. Paste electrode was prepared using Cu2ONPs–C@G (Cu2ONPs–C@G/PE) for voltametric quantification of the musculotropic antispasmodic drug: mebeverine hydrochloride (MEB). The electrochemical behavior of MEB was studied using CV, and the optimum analytical parameters were investigated using square wave adsorptive anodic stripping voltammetry (SWAdASV). Moreover, density functional theory (DFT) was used to emphasize the ability of MEB to form a complex with Cu2+, confirming the suggested electrochemical behavior of MEB at Cu2ONPs–C@G/PE. With good stability and high reproducibility, SWAdASV of Cu2ONPs–C@G/PE shows successful quantification of MEB over the concentration range of 5.00 × 10−11–1.10 × 10−9 M with lower limit of detection (LOD) and lower limit of quantification (LOQ) values of 2.41 × 10−11 M and 8.05 × 10−11 M, respectively. Finally, accurate quantification of MEB in dosage forms (tablets) and biological fluids (spiked human urine and plasma samples) was achieved using Cu2ONPs-C@G/PE.

scholarly journals Application of an LC–MS/MS Method for the Simultaneous Quantification of Homovanillic Acid and Vanillylmandelic Acid for the Diagnosis and Follow-Up of Neuroblastoma in 357 Patients

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3470
Author(s):  
Narae Hwang ◽  
Eunbin Chong ◽  
Hyeonju Oh ◽  
Hee Won Cho ◽  
Ji Won Lee ◽  
...  
Keyword(s):  
Lower Limit ◽  
Large Scale ◽  
Homovanillic Acid ◽  
Limit Of Detection ◽  
Method Comparison ◽  
Vanillylmandelic Acid ◽  
Limit Of Quantification ◽  
Spot Urine ◽  
Minimal Sample ◽  
Clinical Biomarkers

Homovanillic acid (HVA) and vanillylmandelic acid (VMA) are end-stage metabolites of catecholamine and are clinical biomarkers for the diagnosis of neuroblastoma. For the first time in Korea, we implemented and validated a liquid chromatography tandem mass spectrometry (LC–MS/MS) assay to measure urinary concentrations of HVA and VMA according to Clinical and Laboratory Standards Institute guidelines. Our LC–MS/MS assay with minimal sample preparation was validated for linearity, lower limit of detection (LOD), lower limit of quantification (LLOQ), precision, accuracy, extraction recovery, carryover, matrix effect, and method comparison. A total of 1209 measurements was performed to measure HVA and VMA in spot urine between October 2019 and September 2020. The relationship between the two urinary markers, HVA and VMA, was analyzed and exhibited high agreement (89.1% agreement, kappa’s k = 0.6) and a strong correlation (Pearson’s r = 0.73). To our knowledge, this is the first study to utilize LC–MS/MS for simultaneous quantitation of spot urinary HVA and VMA and analyze the clinical application of both markers on a large scale for neuroblastoma patients.

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