Single-Channel Flow Injection Spectrophotometric Determination of Nickel Using Furildioxime in Micellar Solution

A very simple, selective, and fast flow injection spectrophotometeric method is developed for determination of nickel using furildioxime as complexing agent. Micellar solution of brij-35 is employed to solubilize the sparingly soluble complex of Ni-furildioxime in buffered aqueous system (pH-9.00). Under optimized conditions, absorbance is linear from 0.02 to 10 μg mL−1 using 500 μL sample volume and from 10 to 30 μg mL−1 using 50 μL sample volume of nickel at 480 nm, with R2 = 0.9971 and 0.9916, respectively. The molar absorption coefficient and Sandell's sensitivity were 6.0 × 103 L mol−1 cm−1 and 0.01 ng cm−2, respectively. The sample throughput of the method is 120 samples per hour with RSD of 0.01–0.2% for 0.02 to 10 μg mL−1 nickel (n = 5), indicating that the method is highly precise and reproducible. Interference from cobalt is removed by Nitroso R-salt-modified XAD-16. The developed method is validated by analysing certified reference materials and is applied to assess nickel content of commercially available cigarettes

A Novel Micellar Electrokinetic Chromatographic Method for Separation of Metal-DDTC Complexes

Micellar electrokinetic chromatography (MEKC) was examined for the separation and determination of Mo(VI), Cr(VI), Ni(II), Pd(II), and Co(III) as diethyl dithiocarbamate (DDTC) chelates. The separation was achieved from fused silica capillary (52 cm × 75 μm id) with effective length 40 cm, background electrolyte (BGE) borate buffer pH 9.1 (25 mM), CTAB 30% (100 mM), and 1% butanol in methanol (70 : 30 : 5 v/v/v) with applied voltage of −10 kV using reverse polarity. The photodiode array detection was achieved at 225 nm. The linear calibration for each of the element was obtained within 0.16–10 μg/mL with a limit of detection (LOD) 0.005–0.0167 μg/mL. The separation and determination was repeatable with relative standard deviation (RSD) within 2.4–3.3% (n = 4) in terms of migration time and peak height/peak area. The method was applied for the determination of Mo(VI) from potatoes and almond, Ni(II) from hydrogenated vegetable oil, and Co(III) from pharmaceutical preparations with RSD within 3.9%. The results obtained were checked by standard addition and rechecked by atomic absorption spectrometry

Cathodic Stripping Voltammetric Determination of Cefadroxil in Pharmaceutical Preparations and in Blood Serum

Abstract An analytical method has been developed using hanging mercury drop electrode (HMDE) for the quantitative determination of antibacterial drug cefadroxil (CFL) from pharmaceutical preparations and blood serum. Cathodic adsorptive stripping voltammetry was carried out in hydrochloric acid (0.1M): methanol (80: 20 v/v) and potassium chloride (0.1M) as supporting electrolyte. The reduction wave was obtained within -700 to -800 mV. Linear calibration curve was within 1-50µg/mL with detection limit of 0.1µg/mL of cefadroxil. Relative standard deviation for inter and intra day analysis of CFL was within 1-2%. The number of additives present in pharmaceutical preparations did not interfere the determination of cefadroxil. The analysis of pharmaceutical preparations and blood serum after chemotherapy with cefadroxil indicated relative standard deviation (RSD) within 0.8-1.2% and 2.6-3.8% respectively. The satisfactory results were obtained for quality control of cefadroxil in pharmaceutical preparations and in blood serum

Synthesis of new functionalized Calix[4]arene modified silica resin for the adsorption of metal ions: Equilibrium, thermodynamic and kinetic modeling studies

In this study, a new efficient resin-based material has been synthesized through the surface modification of silica by functionalized calix[4]arene and applied for the adsorption of metal ions from aqueous media. The synthesis of functionalized calix[4]arene modified silica (FCMS) resin was characterized by FTIR, CHNS, BET surface area, SEM analyses. The FCMS resin has high thermal and chemical stabilities that were checked by the thermogravimetric analysis and various acidic/basic conditions. The efficiency of the FCMS resin was checked by performing a set of batch experiments under optimized parameters such as concentration of the metal solution, pH, resin dosage, time, temperature, and competitive adsorption in mixed solutions. The results showed that better adsorption has been achieved at pH 7, with 25 mg adsorbent dosage and 10 min contact time. The equilibrium kinetic study showed that the metal adsorption follows the pseudo 2nd order kinetic model with quite high coefficients of determination values (R-2 > 0.99). The experimental data have been validated by applying three adsorption isotherm models and the results revealed that the Freundlich isotherm model (R-2 > 0.99) was the best fit for the adsorption of Cu2+, Pb2+, and Cd2+ ions. However, the sorption energy calculated from the D-R isotherm model for Cu2+, Pb2+, and Cd2+ ions suggested that an ion-exchange mechanism is involved on the surface of the FCMS resin. The thermodynamic data demonstrated that the reaction is spontaneous and endothermic. The FCMS resin was also applied on real wastewater samples and the results demonstrated that the resin has a good ability to treat metal-contaminated wastewater. (C) 2021 Elsevier B.V. All rights reserved

Identification of heavy metal ions from aqueous environment through gold, Silver and Copper Nanoparticles: An excellent colorimetric approach

Heavy metal pollution has become a severe threat to human health and the environment for many years. Their extensive release can severely damage the environment and promote the generation of many harmful diseases of public health concerns. These toxic heavy metals can cause many health problems such as brain damage, kidney failure, immune system disorder, muscle weakness, paralysis of the limbs, cardio complaint, nervous system. For many years, researchers focus on developing specific reliable analytical methods for the determination of heavy metal ions and preventing their acute toxicity to a significant extent. The modern researchers intended to utilize efficient and discerning materials, e.g. nanomaterials, especially the metal nanoparticles to detect heavy metal ions from different real sources rapidly. The metal nanoparticles have been broadly utilized as a sensing material for the colorimetric detection of toxic metal ions. The metal nanoparticles such as Gold (Au), Silver (Ag), and Copper (Cu) exhibited localized plasmon surface resonance (LPSR) properties which adds an outstanding contribution to the colorimetric sensing field. Though, the stability of metal nanoparticles was major issue to be exploited colorimetric sensing of heavy emtal ions, but from last decade different capping and stabilizing agents such as amino acids, vitmains, acids and ploymers were used to functionalize the metal surface of metal nanoparticles. These capping agents prevent the agglomeration of nanoparticles and make them more active for prolong period of time. This review covers a comprehensive work carried out for colorimetric detection of heavy metals based on metal nanoparticles from the year 2014 to onwards. © 202

Reversed-Phase Liquid Chromatographic Separation and Determination of Ni(II), Cu(II), Pd(II), and Ag(I) Using 2-Pyrrolecarboxaldehyde-4-phenylsemicarbazone as a Complexing Reagent

This paper reports the utilization of 2-pyrrolecarboxaldehyde-4-phenylsemicarbazone (PPS) as a complexing reagent for the simultaneous determination and separation of Ni(II), Cu(II), Pd(II), and Ag(I) by reversed-phase high-performance liquid chromatography with UV detector. A good separation was achieved using Microsorb C18 column (150 × 4.6 mm i.d.) with a mobile phase consisted of methanol : acetonitrile : water : sodium acetate (1 mM) (68 : 6.5 : 25 : 0.5 v/v/v/v) at a flow rate of 1 mL/min. The detection was performed at 280 nm. The linear calibration range was 2–10 μg/mL for all metal ions. The detection limits (S/N = 3) were 80 pg/mL for Ni(II), 0.8 ng/mL for Cu(II), 0.16 ng/mL for Pd(II), and 0.8 ng/mL for Ag(I). The applicability and the accuracy of the developed method were estimated by the analysis of Ni(II) in hydrogenated oil (ghee) samples and Pd(II) in palladium charcoal

Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Vegetables Grown in Pakistan

Distribution and risk assessment of eight priority polycyclic aromatic hydrocarbons (PAHs) contents have been examined in different varieties of vegetables grown in Pakistan. The results showed that the total PAH contents were higher for root vegetables like potato and carrot (~13 μg/kg) and relatively lower for turnip (10.9 μg/kg), respectively while for the fruit vegetables, all the peels were found to be more contaminated than cores. The ratio of total PAH concentrations in peels with respect to those of cores is found to be 1.45, 1.26, 1.31, 1.44, 1.40, and 1.36 for potato, turnip, carrot, eggplant, cucumber, and bitter gourd, respectively. For leafy vegetables, cabbage showed maximum PAH (11.6 μg/kg) as compared to the cores of fruit vegetables. Among individual PAH congeners, anthracene showed higher levels in all vegetables. For benzo(a)anthracene, maximum concentration (3.44±2.10 μg/kg) was encountered in turnip cores. Highest benzo(e)pyrene concentration was found in potato (3.19±1.67 μg/kg) followed by turnip (2.74±1.22 μg/kg). Benzo(b)fluoranthene and benzo(k)fluoranthene showed relatively lower levels in all samples studied. All the concentrations of PAHs are presented on a fresh weight basis. The results of human exposure of PAH by consumption of these vegetables showed that cumulative dietary exposure of Pakistani population to PAHs from vegetables ranges from 0.25 μg/p/d to 1.16 μg/p/d

A highly selective nickel-aluminum layered double hydroxide nanostructures based electrochemical sensor for detection of pentachlorophenol

With the widespread use of pesticides, environmental pollution has elevated to a top priority for humans. The pentachlorophenol (PCP) is one of the most dangerous chlorophenols, employed as pesticides, fungicides, and wood preservatives. In the current study, a nickel-aluminum layered double hydroxide modified glassy carbon electrode (Ni-Al-LDH@GCE) was used to build a straight forward, environmentally friendly, and accurate electrochemical sensor for the measurement of PCP. The fabricated Ni-Al-LDH was principally assessed using a variety of characterization methods to confirm its functionalities, morphology, porosity and crytallanity. The proposed Ni-Al-LDH@GCE sensor was also characterized electrochemically for the evaluation of its conductivity using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The linear dynamic range of the developed ultra-sensitive Ni-Al-LDH@GCE based electrochemical method was found as 0.05 to 50 µM at a scan rate of 50 mV/s in Britton-Robinson buffer of pH 6 for PCP. The limit of detection (LOD) and limit of quanitification (LOQ) of electrochemical sensor for PCP were determined as 0.004 μM and 0.0132 μM, respectively. The sensor's analytical suitability was evaluated using real water samples that showed the acceptable recovery values

Preparation of polyaniline montmorillonite clay composites for the removal of diethyl hexyl phthalate from aqueous solutions

<p>The work presents the synthesis of polyaniline functionalized montmorillonite (PANI/MMT) clay composites and evaluation of their performance as an adsorbent for the mitigation of toxic diethyl hexyl phthalate (DEHP) from water. The formation of composite was confirmed by different analytical techniques such as FTIR, zeta potential analysis, XRD, SEM, and AFM. The adsorption capacity of PANI/MMT was superior to MMT. DEHP followed partition mechanism on PANI/MMT whereas MMT favored surface adsorption mechanism. The performance of PANI/MMT for DEHP removal was unaffected by the change in pH of solution, change in salinity, and hardness contents in aqueous system and consecutive adsorption desorption cycles compared to MMT. Furthermore, both PANI/MMT and MMT exhibited greater adsorption capacities as compared to the previously published work and showed satisfactory performance in real water samples.</p