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Smart network management automation (SNMA) is a technology that enables the automation of network management tasks. It provides a platform for automating network management, allowing administrators to manage their networks more reliably and efficiently. It provides the tools to monitor and manage network performance, identify and troubleshoot problems, and automate the deployment of new services and applications. SNMA also allows for scalability to meet the needs of any organization, regardless of size or complexity. With SNMA, network administrators can quickly and accurately identify problems, increase network uptime, and reduce time spent on manual tasks. The SNMA provides the ability to adjust configurations quickly and respond to changes in the network environment. It can help reduce costs and improve the efficiency of network operations. This paper proposed an intelligent network management automation algorithm for network administration and management in 5G communication networks. The proposed algorithm achieved 91.82% of remote network administration, 95.25% of global network administration, 96.59% of urban network administration, and 95.07% of local network administration. It creates a single submission to the network to make configuration changes, register network resources, manage users’ IP addresses, and filter packets to ensure information security and other tasks.

The overuse of antibiotics increases resistant bacteria, and their accumulation in the human body resulting in a pernicious influence or allergic effect on human health. As antibiotics have been used in livestock, their residue in food products is a serious problem. Therefore, the determination of tetracycline (TC) – an antibiotic in food samples by a simple, highly sensitive technique is necessary. This report presents a fluorescence sensor to detect TC based on fluorescence quenching by inner filter effect (IFE) between TC and Cs4PbBr6/CsPbBr3 perovskite material. Cs4PbBr6/CsPbBr3 acts as a fluorescence source with high luminescence quantum yield, narrow emission peak, and short radiative lifetime. It is also protected by perofluorooctyltriethyloxylsilane fluorocarbons assembled on the particle surface to form a water-resistance layer due to the high hydrophobic groups, –CF2– and –CF3, resulting in high aqueous dispersion. Under optimized conditions, the proposed sensor showed high sensitivity and selectivity to detect TC in food samples. The limit of detection is calculated as 76 nM with a linear range of 0.4 – 10 µM. The fluorescence quenching mechanism is assigned to IFE based on the excitation spectrum of Cs4PbBr6/CsPbBr3 and the absorption spectrum of TC, as well as the compensatory fluorescence intensity of Cs4PbBr6/CsPbBr3 with the energy absorbed by TC concentration.

Photocatalytic degradation of pollutants is considered to be an effective green method to remove organic dyes from contaminated water. This research work presents the synthesis of a magnetically recoverable ruthenium-magnetite (Ru/Fe3O4) nanocomposite for the photocatalytic degradation of methylene blue (MB) in an aqueous solution under UV and sunlight radiation. The magnetic Ru/Fe3O4 nanocomposite is synthesized in a single step using the chemical co-precipitation method. The synthesized nanocomposite sample is characterized by various techniques, including, XRD, FT-IR, SEM, TEM, TEM–EDX, XPS and VSM whereas the photocatalytic degradation of MB is analyzed by the UV–Vis spectrophotometer. The formation of ruthenium nanoparticles in magnetic Fe3O4 has been confirmed by TEM, TEM–EDX and XPS studies. The catalytic activity of the synthesized Ru/Fe3O4 nanocomposite is evaluated by photodegradation of the MB dye aqueous solution under UV and sunlight radiation. The influences of various operation parameters on photocatalytic degradation such as pH, dye initial concentration and catalyst dosage are examined. The results revealed a complete photocatalytic degradation of MB in the aqueous solution occurred by exposure to both UV and sunlight radiation. Furthermore, the photocatalytic degradation of MB under UV light is faster than sunlight. The photocatalytic degradation reaction of MB is found to be consistent with the pseudo-first-order kinetics. The strong ferromagnetic nature of Fe3O4 enables the nanocomposite to be separated from the solution for recycling and has a photocatalytic efficiency of greater than 90% for up to five cycles. The synthesized Ru/Fe3O4 photocatalyst efficiently degrades MB dye, so it can be used as a potential catalyst for the removal of MB in aqueous solutions.

We report an ultrasensitive nanohybrid electrochemical DNA sensor developed to detect the LipL32 gene of Leptospira interrogans that causes leptospirosis. A carboxylated multiwalled carbon nanotubes electrode with gold nanoparticles (c-MWCNTs/nano-Au) was modified with polyamidoamine (PAMAM) and graphene quantum dots using cysteine (Cys) as a linker. The c-MWCNTs/nano-Au electrode was covalently bonded to polyamidoamine (PAMAM) via Cys through Au-SH bonding. The amino group of PAMAM was linked to carboxyl moiety of graphene quantum dots (GQD) to form a c-MWCNTs/nano-Au/Cys/PAMAM/GQD nanohybrid electrode. A 5’-amino (NH2) labeled single-stranded DNA (ssDNA) probe based on the LipL32 gene was immobilized on the surface of a c-MWCNTs/nano-Au/Cys/PAMAM/GQD nanohybrid electrode. The different dilutions of single-stranded genomic DNA (ssG-DNA) of L. interrogans were treated on immobilized DNA probe to allow the hybridization. The hybridization events are measured using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) using redox indicators of 1 mM methylene blue and potassium ferricyanide. Field emission scanning electron microscopy (FE-SEM) was performed to analyze the modifications done on the surface of the electrode. The developed nanohybrid sensor has a sensitivity of 1952.3 µA cm−2 ng−1 and a lower limit of detection (LOD) of 0.112 pg/µl (R2 = 0.98). The nanohybrid sensor showed good reproducibility over a period of 6 months, exhibiting only a 10% loss in actual DPV current. The developed nanohybrid sensor is found to be specific to L. interrogans with high sensitivity and reproducibility, and it can be used for routine analysis for L. interrogans identification and leptospirosis diagnosis.

This work describes photocatalytic application of γ-alumina (γ-Al2O3) surface-anchored palladium and palladium oxide nanoparticles (Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs) synthesized by a novel co-precipitation technique. The palladium(0) NPs (Pd-γ-Al2O3) were formed by calcination of the sample in inert medium, whereas PdO NPs (PdO-γ-Al2O3) were obtained by calcination of the sample in atmospheric oxygen. As-synthesized Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs are characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, field emission scanning electron microscopy and photoluminescence (PL) spectra. The PL spectra of Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs display visible-light emissions from 450 to 500 nm at room temperature. This work aims to study the photocatalytic degradation of organic dye pollutants, including bromocresol green (BCG), bromothymol blue, methylene blue and methyl orange using Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs as potential photocatalysts. Experimental parameters, including the admitting concentration of the organic dye solution, Pd-γ-Al2O3 and PdO-γ-Al2O3 photocatalyst dosage, and pH, were varied to ascertain favorable conditions for photocatalytic degradation. The results indicate that the organic dye BCG is completely (100%) degraded in aqueous solution under ultraviolet light, compared with the other organic dyes. Furthermore, Pd-γ-Al2O3 NPs showed better photocatalytic performance than PdO-γ-Al2O3 NPs. The possible photocatalytic degradation mechanism of the organic dyes by Pd-γ-Al2O3 and PdO-γ-Al2O3 photocatalysts is proposed. The studies reveal that Pd and PdO NPs anchored on the γ-Al2O3 surface are promising and effective catalysts for photocatalytic degradation of organic dyes.

Upconversion fluorescence is the process of converting optical energy from low absorption energies to high emission energies. The upconversion (UC) materials exhibit significant advantages such as ...

Abstract: More than 10 million people worldwide have Alzheimer's disease (AD), a degenerative neurological illness and the most prevalent form of dementia. AD's progression in memory loss, cognitive deterioration, and behavioral changes are all symptoms. Amyloid-beta 42 (Aβ42), the hyperphosphorylated forms of microtubule-associated tau protein, and other cellular and systemic alterations are all factors that contribute to cognitive decline in AD. Rather than delivering a possible cure, present therapy strategies focus on reducing disease symptoms. It has long been suggested that various naturally occurring small molecules (plant extract products and microbiological isolates, for example) could be beneficial in preventing or treating disease. Small compounds, such as flavonoids, have attracted much interest recently due to their potential to alleviate cellular stress. Flavonoids have been proven helpful in various ways, including antioxidants, anti-inflammatory agents, and anti-apoptotic agents, but their mechanism remains unknown. The flavonoid therapy of Alzheimer's disease focuses on this review, which includes a comprehensive literature analysis.

The presence of pesticide residues in food and vegetables is a growing concern for consumers. To monitor these residues reliably, a selective and sensitive multiresidue system has been developed and validated in tomato by gas chromatography–tandem mass spectrometry (GC-MS/MS). Titanium-coated graphite with carbon nanotube (CNT) in acrylonitrile–butadiene–styrene (ABS) used as reversed-dispersive solid-phase (extraction materials with modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method. Titanium-coated graphite with CNT-ABS is synthesized, characterized by X-ray diffraction and scanning electron microscopy. The clean-up performance of titanium-coated graphite with CNT-ABS was demonstrated to be better to primary secondary amine and graphitized carbon black cartridges. The processing of two multiple reaction monitoring transformations for each analyte is done using GC-MS/MS in electron impact mode. Satisfactory purification and recovery effects (74%–100%) of 35 pesticides were achieved in tomato matrices when using 5 mg of titanium-coated graphite ABS-CNT nanocomposite. It was observed that quinolphos and deltamethrin are present above the maximum residue limit. The technique proved to be reliable and sensitive in tomato samples for the routine testing of 35 pesticides.

Chronic lung diseases such as asthma, chronic obstructive pulmonary disease, lung cancer, and the recently emerged COVID-19, are a huge threat to human health, and among the leading causes of global morbidity and mortality every year. Despite availability of various conventional therapeutics, many patients remain poorly controlled and have a poor quality of life. Furthermore, the treatment and diagnosis of these diseases are becoming increasingly challenging. In the recent years, the application of nanomedicine has become increasingly popular as a novel strategy for diagnosis, treatment, prevention, as well as follow-up of chronic lung diseases. This is attributed to the ability of nanoscale drug carriers to achieve targeted delivery of therapeutic moieties with specificity to diseased site within the lung, thereby enhancing therapeutic outcomes of conventional therapies whilst minimizing the risks of adverse reactions. For this instance, monoolein is a polar lipid nanomaterial best known for its versatility, thermodynamic stability, biocompatibility, and biodegradability. As such, it is commonly employed in liquid crystalline systems for various drug delivery applications. In this review, we present the applications of monoolein as a novel nanomaterial-based strategy for targeted drug delivery with the potential to revolutionize therapeutic approaches in chronic lung diseases.

In this work, reduced graphene oxide-nickel (RGO–Ni) nanocomposite is synthesized. X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM–EDS (Energy Dispersive X-Ray Spectroscopy) are used to study the crystalline nature, morphology and elemental composition of the RGO–Ni nanocomposite, respectively. As synthesized RGO–Ni nanocomposite is used to develop selective adsorptive removal of Rhodamine B (RhB) dye from the aqueous solution. The experiments have been performed to investigate RhB uptake via RGO–Ni nanocomposites which include, contact time (60 min), initial dye concentration (50 mg/100 ml), adsorbent dosage (0.5 mg) and pH 8 of dye solution. The equilibrium concentration is determined by using different models namely, Freundlich, Langmuir and Tempkin. Langmuir isotherm has been fitted well. Langmuir and Tempkin equations are determined to have good agreement with the correlation coefficient data. The kinetic study concluded that RhB dye adsorption follows with the pseudo-second-order kinetic model. Further, adsorption mechanism of RGO–Ni is proposed which involves three steps. The synthesized adsorbent is compared with the other adsorbents in the literature and indicates that RGO–Ni nanocomposite used in this study shown better results for a particular adsorption capacity than polymeric, natural and synthetic bioadsorbents. The regeneration and reusability experiments suggest RGO–Ni nanocomposite can be used for many numbers of times for purification/adsorption., Reduced graphene-nickel nanocomposite (RGO–Ni); Rhodamine B dye; SEM; XRD; Adsorption kinetics

This work describes photocatalytic application of γ-alumina (γ-Al

We investigated the effect of La substitutional ions on the structural, optical, and electrochemical properties of bismuth ferrite (BiFeO3) and used them as electrode materials for high performance supercapacitors. The compositions of 1.05Bi1-xLaxFeO3 (0.0 x 0.10) nanoparticles were prepared through sol-gel conventional route and denoted as 1.05BiFeO3: BF0; 1.05Bi0.95La0.05FeO3: BF5; 1.05Bi0.90La0.10FeO3: BF10. The Rietveld refinement results of XRD patterns suggested the formation of rhombohedrally distorted perovskite structure (space group: R3c) with negligible secondary phase. The crystallite sizes determined using Scherrer’s formula were found to be in the 59−48 nm range and observed to decrease with an increase in La content. The bandgap measured using UV absorption spectroscopy was found to decrease with an increase in La content in BiFeO3. The SEM micrographs revealed that the prepared samples were composed of nanocrystalline grains with particle sizes ranging from 25 to 40 nm. The electronic structural modification has been confirmed by the XAS analysis of Fe L3,2 and O K edge spectra as a result of La doping. Electrochemical measurements showed that 5% La-doped BFO (BF5) as an electrode demonstrated excellent performance for supercapacitors with a specific capacitance of 328 F g−1 measured with a scan rate of 10 mV s−1. It also exhibited tremendous cyclic stability with capacitance retention of >97 % for 1000 cycles measured at 1A g−1.

Milk adulteration is one of the major global concerns as milk is being consumed as a wholesome dairy product in every part of the world. The fraudulent practice of milk adulteration is on the rise, which is making people apprehensive about the purity and quality of milk. The adulterants such as water, vegetable and animal fat, extraneous proteins and chemical components viz. melamine, urea, formalin, detergents, ammonium sulphate, boric acid, caustic soda, benzoic acid, salicylic acid, hydrogen peroxide and sugars deliberately mixed in milk can be an be harmful to the health of consumers. This necessitates the availability of procedures and technologies that could curb this ill practice of milk adulteration. Over the years, various methods have been developed for the detection of milk adulterants. The chromatographic methods such as HPLC and GC, coupled with mass spectrometry have been used for selective identification as well as detection of different milk adulterants. Immunological techniques such as ELISA and various DNA based procedures like PCR have also been used for the specific detection of some common milk adulterants. Spectroscopic methods, namely FTIR and NIR in association with chemometrics have raised the bar of adulterant detection systems. The equipments such as electronic nose and electronic tongue are some of the fancy procedures used in milk and other food adulterants detection. The biosensors are the detection systems that can be used for rapid and real time detection of milk adulterants. This review brings insight into the biosensor application in milk adulterant detection and also tries to explore the potential of biosensors in identifying some common milk adulterants.

In order to determine the health status of people and provide the most appropriate treatment, rapid and accurate diagnosis is required. Recently all the clinical analysis is piloted in specialized laboratories which require specific and automated instruments. The pre-diagnosis of any disease is important in effective treatment and it becomes a lifesaving option. The conventional disease diagnostic methods require highly skilled labor, use expensive chemicals and are time consuming. They also suffer from problems like less sensitivity and specificity. Biosensors can help address these problems and provide specific, fast diagnosis with low cost, ease of use and portability. Biosensors are instruments which have a capability to detect a biological compound like nucleic acids and proteins. They may be optical, piezoelectric, and electrochemical. This review discusses the role of various biosensors in disease detection and diagnosis. Use of different nanostructured materials in biosensors is also being reviewed. These devices demonstrate appropriate sensitivity, specificity and efficient diagnosis. © 2021 The Authors

Recently, organic ligands have been shown to play a significant role in optical and electronic properties of CdSe quantum dots and also in solar cell applications. We report organic dithiols as novel capping ligands for CdSe quantum dots (QDs). The organic dithiol compounds were designed in such a way that the two thiol groups of a dithiol (acts as a bidentate ligand) can bond directly to an inorganic CdSe QD surface which passivate effectively to show high optical efficiency by promoting interfacial charge transfer. This work would offer a direct and effective pathway to synthesize CdSe QDs that attaches dithiol ligands with aromatic functionality while maintaining the size and shape control of the CdSe QDs. The structure, crystallinity, and optical properties of the dithiol-capped CdSe QDs were analyzed by XRD, TEM, and photoluminescence. The covalent immobilization of dithiols onto CdSe QDs was confirmed by XPS, FT-IR, TGA, XRD and TEM characterizations. Further, the influence of dithiol-type capping ligands on the optical properties of highly luminescent CdSe QDs was investigated. It has been found that the growth rate and the photoluminescence intensity of CdSe QDs were strongly dependent on the type of dithiol ligands. We also experimentally investigated the use of dithiol-capped CdSe QDs in solar cells. The dithiol shell allows for the electron transport from the surface of the QDs, evidenced by better performance as CdSe QDs sensitized solar cells. The power conversion efficiency (η) of CdSe QDs reached up to 0.65%.

nanocatalysts. Click chemistry has recentlyemerged to become one of the most powerful tools in drug discovery, chemical biology, proteomics, medicalsciences and nanotechnology/nanomedicine. In addition, preliminary tests of recycling showed good resultswith neither loss of activity or significant precipitation. Key Words : Ru

The present work reports a chemical co-precipitation process to synthesize palladium (Pd) nanoparticles using alumina as a supporting material. The optimized temperature for the formation of nanocrystalline palladium was found to be 600 °C. The X-ray diffraction (XRD) and Raman spectroscopy were used to study the chemical nature of the Pd in alumina matrix. The surface morphology and properties of the nanocrystalline powders were examined using thermogravimetric analysis (TG–DTA), XRD, Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The calcinations in different atmospheres including in the inert medium forms the pure nano Pd0 while in the atmospheric air indicates the existence pure Pd0 along with PdO nanoparticles. The catalytic activities of the as-synthesized nanocrystalline Pd nanoparticles in the alumina matrix were investigated in Suzuki coupling, Hiyama cross-coupling, alkene and alkyne hydrogenation, and aerobic oxidation reactions.

Separation of enantiomers is one of the most interesting and challenging tasks in the field of separation science. High-performance liquid chromatography (HPLC) and recently capillary electrochromatography (CEC) using chiral stationary phases (CSP) are two of the most useful techniques for both enantioseparation and determination of enantiomeric composition. Although silica has been extensively used as the base material for the stationary phases due to attractive properties including desirable mechanical strength, surface characteristics, catalytic inertness, and surface derivatization possibilities, it has some inherent shortcomings including the narrow range of pH and thermal stability. The zirconia-based stationary phases have shown excellent performance in the separation of wide range of compounds and have been considered as an alternative to silica-based stationary phases due to desirable chemical and physical properties such as resistance to thermal conditions, resistance to extreme pHs, and mechani...

Porous zirconia monolith (ZM) modified with cellulose 3,5-dimethylphenylcarbamate (CDMPC) was used as chiral stationary phaseto separate basic chiral compounds in capillary electrochromatography. The electroosmotic flow behavior of bare and CDMPC-modified zirconia monolithic (CDMPC-ZM) column was studied in ACN/phosphate buffer eluents of pH ranging from 2 to 12. The CDMPC-ZM column was evaluated by investigatingthe influences of pH, the type and composition of organic modifier of the eluent on enantioseparation. CEC separations at pH 9 provided the best resolutions for the analytes studied, which are better than those observed on CDMPC-modified silica monolithic columns under similar chromatographic conditions. No appreciable decline in retention and resolution factors after over 200 injections, and run-to-run and day-to-day repeatabilities of the column of less than 3% indicate the stability of the zirconia monolithic column in basic media.

Cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) is an excellent chiral selector for enantioseparation of a wide variety of chiral compounds. The monolithic chiral columns are becoming popular in liquid chromatography and capillary electrochromatography. In this work, we present the fast separation of chiral β-blockers on a CDMPC-modified zirconia monolithic column by capillary electrochromatography (CEC). The porous zirconia monolithic capillary column was prepared by using the sol-gel technology and then zirconia surface modified with CDMPC. The enantioseparations were performed in reversed-phase (RP) eluents of a phosphate solution (pH 4.4) modified with acetonitrile or alcohol. The enantioseparations of a set of eight chiral β-blockers were achieved in less than one minute. Influences of the applied voltage, column temperature, concentration of acetonitrile and the type of alcohol as the organic modifier in the mobile phase, and sample injection time on enantioseparation were investigated. CEC separations at the applied voltage of 10 kV and 15 °C in the ACN-modified mobile phase provided the best resolutions for the analytes studied. Run-to-run and day-to-day repeatabilities of the column in the RP-CEC separation were less than 1 and 2%, respectively.

A gradient reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for separation and quantitation of impurities in pharmaceutical dosage form of ofloxacin tablets. The developed method was a stability indicating test method for estimation of related impurities generated during synthesis, formulation, and storage of ofloxacin tablets. Forced degradation studies were performed on ofloxacin tablets including acid hydrolysis (5.0 M hydrochloric acid), base hydrolysis (5.0 M sodium hydroxide), oxidation (30% hydrogen peroxide), heat (105°C) humidity degradation 25°C/92% RH/119 b & 40 min, and photolytic degradation (2600 Lux/119 h & 40 min). From the degradation study, the degradation was found between 0–15%. Limit of detection and limit of quantification were established in terms of percentage for all potential impurities. The recovery studies were conducted on finished dosage samples (tablets) for all potential impurities and the average percentage recovery was ranged from 90.8 ...

This paper describes the separation, identification and proposed structures of the degradation products formed during degradation analysis of aripiprazole in its final dosage form by high performance liquid chromatography (HPLC) coupled with quadrupole time-of-flight mass spectrometry (QToF-MS). The drug product was subjected to stress conditions including acid, base, thermal, oxidation, humidity and photolytic degradations. Aripiprazole was found to be stable in all conditions except in thermal and peroxide degradations. The degradation impurities were first separated by HPLC and then identified using QToF mass spectrometry. QToF mass spectrometer provided high order of mass accuracy for unknown impurities and their fragment ions to explore the elemental composition. Based on the fragmentation pattern, the possible structures of the unknown impurities were proposed. To the best of our knowledge, there were no methods available to identify the impurities during degradation of aripiprazole tablets by liquid chromatography-mass spectrometry.

A rapid, sensitive and specific ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–QToF-MS) method has been developed and validated for simultaneous determination of three tetracyclines (TCs) including oxytetracycline, tetracycline, and chlortetracycline in human urine. Human urine sample preparation involves pH adjustment to 4 with hydrochloric acid, pre-concentration, and cleanup by solid phase extraction (SPE) process. The chromatographic separation of all TCs was achieved in less than 5 min using UPLC and ESI-QToF-MS was successfully employed for the identification and quantification. The accurate masses of the product ions were calculated using lock mass correction, and were deviated from the theoretical masses by 0.5–1.9 mDa and 1.1–4.5 ppm, respectively. The developed method was validated in terms of linearity, sensitivity, selectivity, decision limit, detection capability, accuracy, and precision. Limit of detection and limit of quantitation for all TCs were estimated in the range of 0.089–0.138 ng mL− 1 and 0.294–0.455 ng mL− 1, respectively. High overall recoveries of greater than 90% were achieved with linear responses over the 0.5–2 ng mL− 1 range for all TCs in urine samples.

Chirality has become a central theme in scientific research and is an important task in the field of analytical chemistry. In the past few decades, demand for chiral recognition and separation has increased due to the importance of chirality in many fields such as pharmaceutics, chemical industry, agriculture, and biological and clinical analysis. A survey of the literature suggests that different spectroscopic methods are applied to achieve the analysis of chiral enantiomeric compounds. This article is intended to focus on chiral analysis and affords a brief overview on chiral analysis of enantiomeric compounds using different spectroscopic methods, such as fluorescence spectroscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. In this review, primarily the intensive studies of how chiral recognition is achieved and an updated view of the different strategies used up to recognize the chirality of enantiomeric compounds are discussed.

dihydroceramide, M = transition metal ion). The different complexation behavior of copper is responsible for relatively lower affinity of dihydroceramides to copper compared to those of other transition metals. It is also found that in the mass spectrum of the dihydroceramide complexes with copper(II), [2DHCer+Cu-H]

A rapid, simple, sensitive, and selective spectrophotometric method is investigated for the determination of traces of vanadium (V) in foodstuffs, alloy steels, and pharmaceutical, water, soil, and urine samples in aqueous DMF medium. The metal ion forms a green colored complex with 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) in an acidic buffer of pH 6.0. The green colored solution, having an absorbance maximum at 380 nm, is stable for more than 72 hours. Beer's law is obeyed in the range of 0.051–2.037 µg ml−1. The molar absorptivity and Sandell's sensitivity of the method are found as 2.75 × 104 l mol−1 cm−1 and 0.0018 µg cm−2, respectively. The green colored complex has 1:2 [V(V)-HMBATSC] stoichiometry. The stability constant of the complex is determined as 3.267 × 1011 by Job's method. The optimum reaction conditions and other analytical parameters are studied. A sensitive and selective second-order derivative spectrophotometry has also been proposed for the determination of...

A rapid, sensitive, simple and accurate mass spectrometric analysis for the recognition and quantitation of d - and l -thyroxine ( d - and l -T4) was achieved by using kinetic method. The method uses the kinetics of competitive unimolecular fragmentations of trimeric transition metal ion-bound clusters formed under electrospray ionization (ESI). Singly charged cluster ions containing the divalent central metal ion Ca(II)/Mn(II), an amino acid/modified amino acid chiral reference, and the analyte d - and l -T4 were generated by ESI. The cluster ion of interest was mass-selected, and subjected to collision-induced dissociation for undergoing dissociation by competitive loss of either a neutral reference or a neutral analyte. The chiral selectivity (Rchiral), the ratio of the two competitive dissociation rates (abundances of fragment ion) containing the analyte in one enantiomeric form expressed relative to that for the fragments of the other enantiomer, ranges from 0.46 to 3.03. Method by using fixed ligand such as peptide has also successfully improved chiral recognition and quantitative accuracy, which simplifies the dissociation kinetics, in which only the reference ligand or the analyte can be lost. The linear relationship between the logarithm of the fragment ion abundance ratio (ln R) and enantiomeric compositions (ee%) of the T4 allows the chiral purity of enantiomeric mixtures to be determined. The average relative errors were less than 2% between the actual and experimental enantiomeric compositions.

A fixed ligand (FL) version of the kinetic method was applied to rapid, simple, and accurate chiral analysis of DOPA, which is an important drug used for treatment of Parkinson's disease. Singly charged clusters containing the transition metal ion CuII, pyridyl ligands which serve as a fixed ligand, some amino acid as a reference, and the analyte DOPA were generated by electrospray ionization. The cluster ion of interest was mass-selected, and the kinetics of its competitive unimolecular dissociations was investigated in an ion trap mass spectrometer. The chiral selectivity (Rchiral), the ratio of the two fragment ion abundances when the cluster contains one pure enantiomer of the analyte expressed relative to that for the other enantiomer, varies with fixed ligands, references, and transition metals. Chiral discrimination was optimized in 1,10-phenanthroline as a FL, L-Phe and L-Pro as a reference, and Cu(II) as a central metal ion. Quantitative determinations of the enantiomeric composition of DOPA were achieved using two-point calibration curves. The linear relationship between the logarithm of the fragment ion abundance ratio (ln R) and enantiomeric compositions (ee%) of the DOPA allows the determination of the chiral purity of enantiomeric mixtures. Copyright © 2008 John Wiley & Sons, Ltd.