Shot noise sets the limit of quantification in electrochemical measurements

Detection of single molecules, particles, and rapid redox events is a challenge of electrochemical investigations and requires either an amplification strategy or significant averaging for the electrochemical current to exceed the noise level. We consider the minimum number of electrons required to reach the limit of quantification in these electrochemical measurements. A survey of the literature indicates that the state-of-the-art limit in current detection for different types of measurements (e.g. voltammetry, single-molecule redox cycling, ion channel recordings of single molecules, metal nanoparticle collision, and phase nucleation) is independent of the nature of the measurement and increases linearly with reciprocal response time, Δt^?1, over ～5 orders of magnitude (from ～10 to ～10⁶ s^?1). We demonstrate that the practical limit of quantification requires cumulative measurement of ～2100 electrons during Δt and is determined by statistics of counting electrons, that is, the shot noise in the current.     

Preparation of carbon-aerogel polypyrrole composite for desalination by hybrid capacitive desalination method

Capacitive Deionization (CDI) is an emerging technology with great potential applications. Most researchers view it as a viable water treatment alternative to reverse osmosis. This research reports the preparation and application of a carbon aerogel polypyrrole (CA-PPy) composite for the desalination of NaCl solution by the hybrid CDI method. The carbon aerogel (CA) was prepared from a Resorcinol / Formaldehyde precursor by the sol–gel method. The aerogel obtained from the sol–gel was then pyrolysed in a tube furnace to form CA. Polypyrrole (PPy) was prepared by the Oxidative chemical polymerisation of pyrrole, ferric chloride hexahydrate (oxidant), and sodium dodecyl sulfate (dopant). A composite of CA and PPy was then prepared and used to modify carbon electrodes. The CA-PPy composite was characterised to verify its composition, morphology, thermal properties, and functional groups. The electrochemical properties of the material were determined by Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) tests. The electrochemical tests were done using a GAMRY potentiostat electrochemical workstation, a 1.0 M KCl was used as the electrolyte, and the applied potential window was (-0.2 to + 0.6) V for the CV test. The EIS test was done with the same concentration of KCl electrolyte at an applied potential of 0.22 V and at a frequency range of (0.1 – 100, 000) Hz. The optimal specific capacitance of the CA is 115F/g, and that of the composite is 360.1F/g, they were both obtained at a scan rate of 5 mV/s. The CDI desalination study of the CA-PPy composite showed a salt adsorption capacity (SAC) of 10.10 mg/g (300 mg/L NaCl solution) – 15.7 mg/g (800 mg/L NaCl solution) at 1.2 V applied voltage. The salt recovery efficiency of the electrode material in the 300 mg/L solution is 27 %, in the 500 mg/L solution, it is 20.12 %, and in the 800 mg/L solution, it is 15.41 %. The electrode material also showed good electrochemical stability after nine cycles of ion adsorption/desorption study.     

Enhanced photocatalytic degradation of nitrobenzene using MWCNT/β-ZnMoO4 composites under UV light emitting diodes (LEDs)

The β-ZnMoO₄/MWCNT nanocrystal composites were synthesized using hydrothermal method. The physicochemical properties such as structure, morphology and bandgap of synthesized photocatalysts were characterized using PXRD, UV-vis DRS, FTIR, FT-Raman, SEM and TEM analytical methods. PXRD pattern shows the peak shift in the case of synthesized ZnMoO₄/MWCNT which confirms the formation of nanocomposites. Moreover, the strong absorbance in UV region which was evidenced in UV-vis DRS spectra for all the case of synthesized ZnMoO₄ and ZnMoO₄/MWCNT composites. From the SEM and TEM images, the MWCNT was found to have adhered over the ZnMoO₄ nanocrystals. Compared to bare β-ZnMoO₄, β-ZnMoO₄/MWCNT nanocrystal composites exhibited significant higher photocatalytic activity under ultraviolet light emitting diodes (UVLEDs) irradiation for the degradation of nitrobenzene (NB; 2.606 × 10^?4 M). This may be due to the effective charge transfer in the composite and optimized electron hole pair recombination. The photocatalytic activity of the synthesized photocatalysts was also studied under visible LEDs and it is observed that the photocatalytic degradation of NB was 97%, 77%, 65% and 52% under the irradiation of UV, blue, green, and red LEDs respectively.     

An ultrasensitive electrochemical immunosensor for CA72-4 based on a signal amplification strategy of MoS2 nanoflower-supported Au nanoparticles

Accurate detection of cancer antigen 72-4 (CA72-4), a tumor-associated glycoprotein, is of great significance for gastric cancer diagnosis and immunotherapy monitoring. Modification of noble metal nanoparticles on transition metal dichalcogenides can significantly enhance functions, such as electron transport. Molybdenum disulfide gold nanoparticles nanocomposites (MoS₂-Au NPs) were prepared in this study and a series of characterization studies were carried out. In addition, a label-free, highly sensitive electrochemical immunosensor molybdenum disulfide -Au nanoparticles/Glassy carbon electrode (MoS₂-Au NPs/GCE) was also prepared and used for the detection of CA72-4. The electrochemical performance of the immunosensor was characterized by electrochemical techniques, such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The results indicated that better MoS₂-Au NPs nanomaterials have been synthesized, and the prepared electrochemical immunosensor, MoS₂-Au NPs/GCE, showed excellent electrochemical performance. The sensor exhibited high detection sensitivity under optimal conditions, including an incubation time of 30 min, an incubation temperature of 25 °C, and a pH of 7.0. The electrochemical immunosensor also had a low detection limit of 2.0 × 10^?5 U/mL (S/N = 3) in a concentration range of 0.001–200 U/mL, with good selectivity, stability, and repeatability. In conclusion, this study provided a theoretical basis for the highly sensitive detection of tumor markers in clinical biological samples.     

Paper-based diagnostic platforms and devices

Paper-based analytical devices have become lately “must have” components in equipment and instrumental designed for point-of-care applications, especially when they are used in tandem with microfluidic platforms. Nowadays, paper-based electrochemical devices (PEDs) represent the first choice in the development of lab-on-a-chip biosensors because of their benefits in biomedical diagnosis in terms of simplicity, affordability, portability, and disposability. Moreover, cellulose is a biodegradable and biocompatible substrate, ideal for building disposable devices for use in remote locations or low-resource settings. Despite their low costs and simplicity, PEDs must face a tough challenge—meeting the affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to end users criteria. The latest achievements in microfluidic PEDs for clinical diagnosis will be critically discussed, putting emphasis on innovative assay formats and methods for surface modification.     

Hydrides compounds for electrochemical applications

Hydrides have been used since a long time for solid-state hydrogen storage and electrochemical nickel-metal hydride batteries. Besides these applications, growing attention has been devoted to their development as anode materials, as well as solid electrolytes for Li-ion and other ion batteries. Herein, we review and summarize the recent advances of hydrides as negative electrodes for Ni-MH and A-ion batteries (A = Li, Na), and as electrolyte for all solid-state batteries (ASSB). Metallic hydrides such as intergrowth compounds are highlighted as the best compromise up to now for Ni-MH. Regarding anodes of Li-ion batteries, MgH₂, especially its combination with TiH₂, provides very promising results. Complex hydrides such as Li-borohydride and related closo-borates and monovalent carborate boron clusters appear to be very attractive as solid electrolytes for Li-based ASSB, whereas closo-hydroborate sodium salts and closo-carboborates are investigated for Na- and Mg-ASSB. Finally, further research directions are foreseen for hydrides in electrochemical applications.     

Ethanol leaf extract of Ruspolia hypocrateriformis abrogated hepatic redox imbalance and oxidative damage induced by heavy metal toxicity in rats

Humans and animals are frequently exposed to heavy metals in the environment, which are highly toxic to the physiological milieu and organs of the body. We investigated the ameliorative potentials of ethanol leaf extract of Ruspolia hypocrateriformis against redox imbalance due to exposure of rats to heavy metals. The in vitro study explored the antioxidant potentials of the ethanol leaf extract using 1,1-diphenyl-2-picryl hydrazyl, nitric oxide and ferric reducing antioxidant potential assays respectively. HPLC was used to quantify the amount of flavonoids and phenolic acids in the extract. For in vivo study, 30 rats were randomly divided into 5 groups. Group A received normal saline. Group B received combined solution of Lead Nitrate and Mercury Chloride (11.25 mg/kg and 0.4 mg/kg) per Bwt/day. Group C, D and E were administered with the leaf extract at doses of 200, 400 and 600 mg/kg body weight respectively for 28 consecutive days. Biomarkers of hepatic dysfunctions and oxidative stress were investigated in the study rats. The HPLC study revealed high amount of gallic and ferulic acids (17.86 ± 2.68), which are the major phenolic compounds found in the extract. The extract further exhibited high antioxidant potentials in inhibiting the scavenging activity of free radicals produced in vitro. Interestingly, 600 mg/kg dosage of the leaf extract successfully ameliorated the distorted redox imbalance and oxidative damage in the liver of the rats caused by exposure to the heavy metals. Leaf extract of Ruspolia hypocrateriformis demonstrated strong antioxidant potentials, which could be exploited in pharmaceutical preparations.     

Efficient synthesis of magnetic nanoparticle-Musa acuminata peel composite for the adsorption of anionic dye

The impregnation of magnetite (Mt) nanoparticle (NPs) onto Musa acuminata peel (MApe), to form a novel magnetic combo (MApe-Mt) for the adsorption of anionic bromophenol blue (BPB) was studied. The SEM, EDX, BET, XRD, FTIR and TGA were used to characterize the adsorbents. The FTIR showed that the OH and CO groups were the major sites for BPB uptake onto the adsorbent materials. The average Mt crystalline size on MApe-Mt was 21.13 nm. SEM analysis revealed that Mt NPs were agglomerated on the surface of the MApe biosorbent, with an average Mt diameter of 25.97 nm. After Mt impregnation, a decrease in BET surface area (14.89 to 3.80 m²/g) and an increase in pore diameter (2.25–3.11 nm), pore volume (0.0052–0.01418 cm³/g) and pH point of zero charge (6.4–7.2) was obtained. The presence of Pb(II) ions in solution significantly decreased the uptake of BPB onto both MApe (66.1–43.8%) and MApe-Mt (80.3–59.1%), compared to other competing ions (Zn(II), Cd(II), Ni(II)) in the solution. Isotherm modeling showed that the Freundlich model best fitted the adsorption data (R² > 0.994 and SSE < 0.0013). In addition, maximum monolayer uptake was enhanced from 6.04 to 8.12 mg/g after Mt impregnation. Kinetics were well described by the pseudo-first order and liquid film diffusion models. Thermodynamics revealed a physical, endothermic adsorption of BPB onto the adsorbents, with ΔH^o values of 15.87–16.49 kJ/mol, corroborated by high desorption (over 90%) of BPB from the loaded materials. The viability of the prepared adsorbents was also revealed in its reusability for BPB uptake.     

Eco-friendly synthesis of size-controlled silver nanoparticles by using Areca catechu nut aqueous extract and investigation of their potent antioxidant and anti-bacterial activities

Silver nanoparticles (AgNPs) have attracted considerable attention owing to their unique biological applications. AgNPs synthesized by plant extract is considered as a convenient, efficient and eco-friendly material. In this work, the aqueous extract of Areca catechu L. nut (ACN) was used as the reducing and capping agents for one-pot synthesis of AgNPs, and their antioxidant and antibacterial activities were investigated. UV (Ultra Violet)-visible spectrum and dynamic light scattering (DLS) analysis revealed that the size of AgNPs was sensitive to the synthesis conditions. The synthesized AgNPs were composed of well-dispersed particles with an small size of about 10 nm under the optimal conditions (pH value of extract was 12.0; AgNO₃ concentration was 1.0 mM; reaction time was 90 min). In addition, scanning electron microscope with energy dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD) results further verified that the synthesized AgNPs had a stable and well-dispersed form (Zeta potential value of ?30.50 mV and polydispersity index of 0.328) and a regular spherical shape (average size of 15–20 nm). In addition, Fourier transform infrared spectrometry (FTIR) results revealed that phytochemical constituents in ACN aqueous extract accounted for Ag⁺ ion reduction, capping and stabilization of AgNPs. The possible reductants in the aqueous extract of Areca catechu L. nut were identified by high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (HPLC-ESI-qTOF/MS) method. More importantly, the synthesized AgNPs indicated excellent free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH, IC₅₀ = 11.75 ± 0.29 μg/mL) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS⁺, IC₅₀ = 44.85 ± 0.37 μg/mL), which were significant higher than that of ascorbic acid. Moreover, AgNPs exhibited an enhanced antibacterial activity against six selected common pathogens (especially Escherichia coli and Staphylococcus aureus) compared with AgNO₃ solution. In a short, this study showed that the Areca catechu L. nut aqueous extract could be applied for eco-friendly synthesis of AgNPs.     

Investigating the binding measurements of human α-acid glycoprotein with chlorambucil and dacarbazine in the presence of imidazolium based -ionic liquid by affinity capillary electrophoresis

Human alpha (α1)-acid glycoprotein (AGP) is an acute phase protein whose plasma concentration increases several-folds in the presence of various diseases. The variability in AGP plasma concentration is expected to have a huge impact on the drug binding equilibrium. Therefore, a precise measurement of AGP-drug binding is of great demand for drug development. In the current study, an ionic liquid-based aqueous two-phase system combined with affinity capillary electrophoresis (ILATPS/ACE) was utilised in order to improve the accuracy of AGP-drug binding analysis through the measurements of electrophoretic mobilities. The utilisation of ILATPS has shown to have a positive impact on the stability of AGP activity solution during the storage for an extended period of time. In addition, the effect of various alkyl chains (C2-C10) of imidazolium-based ILs with concentrations ranging between 10.00 and 1000.0 μmol L⁻¹ on the AGP binding with the anti-cancer drugs chlorambucil (CHL) and dacarbazine (DAC) was examined by the system developed (ILATPS/ACE). A 100.00 μmol L⁻¹ 1-ethyl-3-methylimidazolium chloride (EMImCl) prepared in the physiological buffer conditions containing AGP (5.00–100.00 µmol L⁻¹) has provided an accurate apparent binding constant of 1.99 ± 0.11 and 6.95 ± 0.14 L mmol⁻¹ with CHL and DAC respectively. Apart from the ACE analysis, EMImCl/phosphate buffer solution was found to be a distinguished system that could lengthen the stability of AGP activity for a period of time reaching 90 days during the solution storage at 4.00 °C. This effect is thought to be due to the easy conversion of one-phase EMImCl/phosphate buffer/AGP at the ambient lab temperature into the two-phase solution at refrigerator temperature, 4.00 °C, and vice versa. Therefore, the ILATP/ACE system could be used to enhance the accuracy for other AGP-drug bindings with a fast, easy to use, and cost-effective analysis.     

Microfluidics and electrochemistry: an emerging tandem for next-generation analytical microsystems

Microfluidic and electrochemical technologies have been at the forefront of the development of emerging analytical microsystems. Microfluidics and electrochemistry show a synergistic relationship, empowering their inherent features. Thus, integration of microfluidics and electrochemical (bio)sensors is envisioned as a powerful tandem for boosting the next generation of lab-on-a-chip platforms, including point-of-care and point-of-need systems. In this review, a general overview of the advantages, drawbacks, and gaps as well as remaining challenges and future trends of coupling microfluidics and electrochemical cells is presented. Special attention is given to the manufacturing and scale-up of the integrated devices and all those aspects that can push on the development of true lab-on-a-chip platforms for reaching the industrial domain and actual commercialization.     

Ascorbic acid supported Carboxymethyl cellulose stabilized silver nanoparticles as optical nanoprobe for Au3+ detection in environmental sample

Heavy metals (HMs), pollution of major environmental matrices and its attendant effects on human health and the environment, continue to generate huge scientific interest, particularly in monitoring and detection. Herein, the optical property of carboxymethyl cellulose stabilized silver nanoparticles (CMC-AgNPs), supported with ascorbic acid, is exploited as a colorimetric probe for the detection of toxic Au³⁺ ion in solution. The as-synthesized CMC-AgNPs showed sharp absorption maximum at 403 nm, with sparkling yellow color and average particles size distribution less than 10 nm. It was further characterized using ATR-FTIR, TEM, FESEM/EDS, XRD and DLS/zeta potential analyzer. Au³⁺ ion detection strategy involves the addition of ascorbic acid (AA) to a pH adjusted CMC-AgNPs, followed by the analyte addition. AA would facilitate the reduction of Au³⁺ on CMC-AgNPs (seed), with resultant color perturbations from light yellow to yellow, orange, ruby red and purple red, under 8 min incubation, at room temperature (RT). The CMC-AgNPs could also serve as a catalyst, by promoting AA mediated reduction of Au³⁺, in-situ. Moreover, we propose, that the color and the absorption spectra change is attributed to the deposition of gold nanoparticles (AuNPs), on the CMC-AgNPs/AA probe, to form (CMC-Ag@Au) nanostructures, depending on the analyte concentration. Absorbance ratio (A₅₄₀/A₄₀₃) showed good linearity with Au³⁺ concentration from 0.25 to 100.0 µM, and an estimated LOD of 0.061 µM. The assay was applied to Au³⁺ detection in environmental wastewater sample, showing satisfactory real sample detection potentiality.     

Nanoparticles: Properties,applications and toxicities

This review is provided a detailed overview of the synthesis, properties and applications of nanoparticles (NPs) exist in different forms. NPs are tiny materials having size ranges from 1 to 100 nm. They can be classified into different classes based on their properties, shapes or sizes. The different groups include fullerenes, metal NPs, ceramic NPs, and polymeric NPs. NPs possess unique physical and chemical properties due to their high surface area and nanoscale size. Their optical properties are reported to be dependent on the size, which imparts different colors due to absorption in the visible region. Their reactivity, toughness and other properties are also dependent on their unique size, shape and structure. Due to these characteristics, they are suitable candidates for various commercial and domestic applications, which include catalysis, imaging, medical applications, energy-based research, and environmental applications. Heavy metal NPs of lead, mercury and tin are reported to be so rigid and stable that their degradation is not easily achievable, which can lead to many environmental toxicities.     

Effect of potassium permanganate on morphological,structural and electro-optical properties of graphene oxide thin films

This work investigated the effect of Potassium Permanganate (KMnO₄) on graphene oxide (GO) properties, especially on electrical properties. The GO thin films were deposited on a glass substrate using drop casting technique and were analysed by using various type of spectroscopy (e.g. Scanning Electron Microscopy (SEM), Ultra- Violet Visible (UV–VIS), Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), optical band gap, Raman Spectroscopy). Furthermore, the electrical experiments were carried out by using current–voltage (I-V) characteristic. The GO thin film with 4.5 g of KMnO₄ resulted in higher conductivity which is 3.11 × 10^?4 S/cm while GO with 2.5 g and 3.5 g of KMnO₄ achieve 2.47 × 10^?9 S/cm and 1.07 × 10^?7 S/cm, respectively. This further affects the morphological (SEM), optical (band gap, UV–Vis, FTIR, and Raman), and crystalline structural (XRD) properties of the GO thin films. The morphological, elemental, optical, and structural data confirmed that the properties of GO is affected by different amount of KMnO₄ oxidizing agent, which revealed that GO can potentially be implemented for electrical and electronic devices.     

Application of stress induces ascorbate peroxidases of S. polyrhiza for green-synthesis Cu nanoparticles

The objective of this study was to assess the effects of stress on physiology/biochemical component of S. polyrhiza and its impact on CuNPs synthesis and bioethanol production. NaCl with RV5 provokes oxidative stress in S. polyrhiza and significantly increase MAD, Proline, H₂O₂, ROS, SOD and APX activity compare to control condition. Starch accumulation in S. polyrhiza was found 354% higher and correspond 4.4 times higher ethanol yield under stress condition compare to control. CuNPs were synthesized with an average size of 23–26 nm by purified fraction of APX having 37 KDa MW, 1.44 IU specific activity. Synthesized CuNPs were stable up to 15 consecutive cycles and potency against wide range of reactive dyes. The maximum remedial efficiency of synthesized CuNPs for COD and BOD was 55263.3 ± 3298.5 mg/m³min. and 30560.3 ± 1987.5 mg/m³min. respectively for RV5 wastewater. 0.072 mg/g of bioethanol was produced from the wet pulp remaining after nanoparticles synthesis. High efficiency of CuNPs and significant production of Ethanol, indicate that the feasibility for circular model for continuous industrial wastewater treatment.     

UV/TiO2 photodegradation of metronidazole,ciprofloxacin and sulfamethoxazole in aqueous solution: An optimization and kinetic study

Emerging pharmaceutical ingredients (APIs) like sulfamethoxazole (SMX), metronidazole (MNZ) and ciprofloxacin (CIP) are biopersistent and toxic to the environment and public health. In this study, UV/TiO₂ photodegradation was applied in the degradation of SMX, MNZ and CIP individually and in a mixture. For a 5 mg/L SMX solution, about 97% of SMX was degraded within 360 min, which was reduced to 80% for 80 mg/L of SMX solution at the same TiO₂ dosage and photodegradation time. The maximum removals of MNZ and CIP as individual components were 100% and 89%, respectively at 600 min of photodegradation reaction time. For binary mixtures, the highest removal (100%) was achieved for MNZ and CIP ([MNZ] = [CIP] = 40 mg/L) mixture at 120 min whereas the degradations were 97% and 96% for SMX and MNZ, and SMX and CIP binary mixtures, respectively, even after 600 min of experimental time at the same concentrations. For tertiary mixture, the maximum degradation 99% was observed for (SMX = CIP] = 20 mg/L and [MNZ] = [40 mg/L) at 600 min. The observed reaction rate was 0.01085 min^?1 when SMX concentration was 5 mg/L, which decreased to 0.00501 min^?1 for SMX concentration of 80 mg/L, indicating decreasing of reaction rate at higher concentration. The results indicate that the UV/TiO₂ process is promising to apply for the treatment of pharmaceutical wastewaters.     

Influence of extractions on physicochemical characterization and bioactivity of Piper nigrum oils: Study on the non-isothermal decomposition kinetic

Black pepper oils have been investigated frequently in the recent years. However, there is a significant variation in physicochemical properties and bioactivity of oils depended on extraction techniques. In this study, the systemic investigation of four various extraction methods was performed to evaluate the physicochemical characterizations, antioxidant and antibacterial activity. The investigation of ¹H NMR, FTIR and UV–Vis spectra confirmed presence of non-volatile components in oils extracted through supercritical CO₂ and hexane-soaking extractions which induced their typical thermal properties. The isothermal behaviour of extracted oils related to evaporation was within range of 3.2–7.3% (w/w) at 27 °C. The SEM images of the black pepper confirmed different operation manners of mechanism between extractions using the solvents and heating process. The lowest MIC for both essential oils from conventional hidrodistillation and microwave-assisted hidrodistillation against two bacteria including E. coli and B. subtilis were found to be 137 µg mL⁻¹. The non-isothermal decomposition kinetics were investigated on the essential oil of microwave-assisted hydrodistillation extraction. The activation energies and pre-exponent factors of non-isothermal decomposition were found to be in range of 36.5–73.7 KJ mol⁻¹ and 4.98 × 10³–1.97 × 10⁸ s⁻¹, respectively, dependent on conversional fractions of the oil. The results revealed that chemical components, physicochemical properties and bioactivity of black pepper essential oils depended on the extraction techniques.     

Paramagnetic surface active ionic liquids: synthesis,properties, and applications

Paramagnetic surface active ionic liquids (PMSAILs) classify task-specific ionic liquids with magnetic properties by incorporating metal into the cationic or anionic part of the ionic liquid. Paramagnetic ionic liquids had long-chain either in cations or anions and showed excellent surface activity and magnetic properties without any need for the magnetic nanoparticles. These PMSAILs have inherent unique ionic liquid properties and self-assembled into various nano-aggregates such as micelles, vesicles, rod-like micelles, and etc., by modification in the structure of cations or anions. PMSAILs provide stimuli-responsive properties, which is one of the essential aspects of targeted applications. The appropriate functional tunability of anions and cations in PMSAILs leads to various multifaceted chemical and biological applications. A new emerging trend in PMSAIL research is hybridization with flexible materials. This review will mainly deal with the synthesis, characterization, and brief history of PMSAILs and their potential advantages in the various applications in micellar catalysis, purification and separation of biomolecules, compaction and decompaction of DNA, drug delivery, and other biomedical applications.     

Antitubercular and antioxidant activities of hydroxy and chloro substituted chalcone analogues: Synthesis,biological and computational studies

A series of chalcone analogues (1–15) were synthesized by Claisen-Schmidt condensation in good yields (70–95%) and characterized by FT-IR, ¹H NMR and mass spectral methods. Additionally, compounds 3 and 7 were characterized by ¹³C NMR. Antitubercular and antioxidant activities of the chalcones were evaluated by MABA and DPPH free radical assays. In MABA assay analogues 3 (MIC = 14 ± 0.11 µM) and 11 (MIC = 14 ± 0.17 µM) bearing fluorine and methoxy groups at para and meta positions were 1.8-times more active than the standard pyrazinamide (MIC = 25.34 ± 0.22 µM). The chalcone analogues such as compound 7 (IC₅₀ = 4 ± 1 µg/mL) containing electron releasing groups such as OH at ortho position had slightly more antioxidant activity than Gallic acid (IC₅₀ = 5 ± 1 µg/mL). The potential compounds 3, 7, 9 and 11 were less selective and toxic against human live cell lines-LO2. Further, molecular docking results of chalcones against anti-tubercular drug target isocitrate lyase (PDB ID: 1F8M) revealed that compound 3 and 11 shown least binding energies as ?7.6, and ?7.5 kcal/mol are in line with in vitro MABA assay, suggesting that these compounds 3 and 11 are strong inhibitor of isocitrate lyase. SwissADME programme estimated the drug likeliness properties of compounds 3, 7, 9 and 11. The lead molecules arisen through this study helps to develop new antitubercular and antioxidant agents.     

Modified QuEChERS method for phenolic compounds determination in mustard greens (Brassica juncea) using UHPLC-MS/MS

A modified QuEChERS method (Quick, Easy, Cheap, Effective, Rugged, and Safe) for the determination of fifteen phenolic compounds in mustard greens (Brassica juncea) using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) analysis was developed. The QuEChERS partitioning step and dispersive solid phase extraction (d-SPE) clean-up sorbents were investigated, aimed at phenolic compound extraction and pigment removal, respectively. QuEChERS acetate version combined with 25 mg of diatomaceous earth (DE) and 5.0 mg of graphitized carbon black (GCB) provided the best conditions for sample preparation of the target compounds. Under the optimized conditions, all phenolic compounds showed good linearity (r ≥ 0.99) over the concentration range of 0.1 to 8000 μg kg⁻¹, and the quantification limits were in the range of 0.06–230 μg kg⁻¹. The spectrophotometric analysis showed that the clean-up step promoted a significant removal of chlorophyll, which is the major pigment present in the sample. Furthermore, antioxidant activity analysis was also carried out after the clean-up step and, together with chromatographic data, showed that no significant retention of the phenolic compounds occurs in the clean-up step. Two mustard greens varieties – Southern Giant Curled (SGC) and Florida Broadleaf (FB) - were analyzed with the proposed method. Seven phenolic compounds (4-hydroxybenzoic, p-coumaric, ferulic and sinapic acids, naringenin, apigenin and kaempferol) were found in both varieties, the greatest abundance being for sinapic acid (1261.5 ± 23 μg kg⁻¹ in SGC and 1235.5 ± 26 μg kg⁻¹ in FB) and ferulic acid (2861 ± 24 μg kg⁻¹ in SGC and 3204.5 ± 45 μg kg⁻¹ in FB).