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Electrolytes that achieve highest Li Coulombic efficiency display quantifiably higher rates of electrochemical Li+ exchange. The effect is attributed to their improved SEI and better-percolated Li deposits that boost Li+ exchange as the cell cycles.

Pesticide residues in vegetables (watercress, mustard green, choy sum, daikon, okra, and yam) from Mekong Delta, Vietnam were analysed by liquid chromatography-tandem mass spectroscopy (LC-MS/MS). QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction, matrix-matched calibration, and dynamic multiple reaction monitoring methods were used. The linear range used was 5 - 200 ng/mL, resulting in R2 > 0.99. The recovery was satisfactory with values within 74.47 - 116.93%, and the RSD was < 15% for most compounds. The percentage of samples with residues above the maximum residue levels (MRLs) was 59%. Pesticide residues were detected above their MRLs in samples of watercress (47%), mustard green (80%), choy sum (83%), daikon (87%), and yam (60%). The results indicated the prevalence of pesticide residues in commonly consumed vegetables in Vietnam, and emphasised the urgent need to develop comprehensive intervention measures to reduce the potential health risk to consumers.

Magnesium silicate is a porous material with a large specific surface area and is easily adsorbed. In particular, it is widely used commercially because it is very effective for adsorbing Na+, K+ ions and other catalysts. However, if the powder is used as an adsorbent as is, there are disadvantages, in that the adsorbed material is easily lost during the adsorption action and becomes difficult to recover. In this study, magnesium silicate was used as an adsorbent to remove pollutants (CO2) from the atmosphere. In addition, in order to overcome the disadvantages of using a powder adsorbent material, an inorganic binder (clay) and a reinforcing agent (glass fiber) were added to prepare a molded article which imparted strength to the adsorbent material. Changes in the properties of the adsorbent were confirmed. Changes in the physicochemical properties of the adsorbed material according to the calcination temperature, from 400 to 800°C, were confirmed. In addition, it was confirmed that a molded body with 15 wt% inorganic binder and 4 wt% reinforcing agent had a specific surface area of about 87 m²/g and a strength of 4.63 N. The prepared molded article could adsorb about 0.41 mmol/g of CO2 at atmospheric pressure, confirming its potential use as a CO2 adsorbent.

The insulator-to-metal phase transition from VO2(M1) to VO2(R) results in extensive improvements in electrocatalytic activity for both the OER and the HER.

The substitutional solid solution Mn1-xVxP compounds are proposed as a high performance anode for lithium ion batteries (LIBs) through a novel alloying/insertion hybrid electrochemical reaction concept by combining alloying reaction-type MnP and insertion reaction-type VP. The solid solution series of Mn1-xVxP are successfully synthesized via a facile high energy mechanical milling. Their electrochemical properties as an anode for LIBs are systematically studied and compared with those of MnP/VP mixture, particularly focusing on the verification of simultaneous alloying/insertion hybrid electrochemical reaction in the solid solution compounds. The Mn0.75V0.25P solid solution electrode shows the excellent high rate cyclability delivering the reversible capacity of 321 mAh g−1 after 5000 cycles at a high current density of 1.0 A g−1, resulting from the synergistic effects of two reaction mechanisms. The homogeneously substituted vanadium ions enable the alloying/insertion hybrid electrochemical reaction in a Mn1-xVxP single phase, which can effectively reduce the rate of volume change, hinder the pulverization and agglomeration of alloying reaction-type Li-Mn-P crystallite during cycling, and ensure the fast electron and ion transport. This simple, yet innovative, solid solution design with the consideration of structural relationships and electrochemical properties inspires the development of advanced ternary or multi-component compound electrode materials for LIBs or other energy storage devices.

In Vietnam, Physalis angulata L. is a wild species growing throughout the country that is often used in traditional medicine. The aim of study was to quantify seven major compounds, including phenolic acids (chlorogenic acid, caffeic acid, p-coumaric acid) and flavonoids (rutin, quercitrin, quercetin, and kaempferol) in three aerial parts of P. angulata. Chromatographic separation was carried out on a Kromasil C18 column (150 mm × 4.6 mm i.d., 5 µm) with a gradient elution of 0.1% formic acid in acetonitrile, 0.2% ammonium acetate/0.1% formic acid in water and methanol at a flow rate of 1.0 mL/min; detection was at 250 and 300 nm. The limits of detection and quantification were in the ranges of 0.1–0.3 and 0.3–1.0 µg/mL, respectively. The validated method was successfully applied to analyze active compounds in P. angulata and may be a useful tool for quality control of this plant.

A simple and reliable high-performance liquid chromatography method was developed to determine the enantiomeric impurity of tenofovir disoproxil fumarate, an orally bioavailable prodrug of tenofovir, commonly used for the treatment of human immunodeficiency virus and hepatitis B. Tenofovir disoproxil and its enantiomer, were completely separated on a Chiralpak IC column (3 μm, 100 × 4.6 mm, i.d.). The chiral separation was achieved using a mobile phase containing n-hexane, ethanol, methanol, and triethylamine 65/25/10/0.1 (v/v/v/v) at a flow rate of 0.6 mL/min. Ideally, the reversal of enantiomer elution order was achieved on the Chiralpak IC column, to allow the elution of the minor enantiomeric impurity before the major component. Moreover, the proposed method was able to discriminate the active ingredient from the related substances available in the tenofovir disoproxil fumarate raw materials. These compounds were isolated and structurally elucidated by MS and nuclear magnetic resonance. Based on the spectral data, the structures of related substances were confirmed as tenofovir isoproxil monoester and fumaric acid. The high-performance liquid chromatography method was optimized by the design of experiment approach and successfully validated following the International Conference on Harmonization guideline. Proposed method was effectively applied for the quantification of enantiomeric impurity in tenofovir disoproxil fumarate raw materials.

A simple and inexpensive liquid chromatography diode array detector (LC-DAD) procedure has been developed to analyse food dyes in beverages, candies, jams, salted fish, Chinese sausage, and cake. A reverse stationary phase provided sufficient selectivity and chromatographic performance for the separation of 11 water-soluble dyes (tartrazine, amaranth, indigo carmine, ponceau 4R, sunset yellow, allura red, carmoisine, fast green FCF (Food green 3), brilliant blue, quinoline yellow, and indocyanine green). The samples were extracted with 1% ammonium solutions and acetonitrile, purified, and concentrated using a C18 solid-phase extraction (SPE) cartridge for beverages, and weak anion exchange SPE cartridge for solid samples. They were determined using a reverse-phase C18 column with gradient elution of 0.2% ammonium acetate buffer, and acetonitrile as the mobile phase. Multiple-specific wavelengths were used to monitor the dyes in the visible range to provide higher sensitivity and an expanded scope for a large number of analytes. The limit of detection and limit of quantification of the dyes were in the range of 0.2 - 0.5 and 0.5 - 1.0 µg/mL, respectively. The precision of the method ranged from 2.71 to 6.31%, while recovery ranged from 90.8 to 105.6%. The validated method was successfully applied to the quantitative analysis of 11 water-soluble dyes in 36 commercial products obtained from the local supermarket. Application to the analysis of beverages and food samples available to consumers proved that the described methods are suitable for the routine analysis of dyes in food products containing a broad range of dyes.

Despite being a leading candidate to meet stringent energy targets of Li-ion batteries, the lithium (Li) metal anode has yet to achieve Coulombic efficiency (CE) requirements for long cycle life (>99.9%), particularly at high rates (>1 C). These limitations derive from the native solid electrolyte interphase (SEI) which, among multiple functions, stabilizes and protects deposited Li. The SEI also plays a critical role in regulating Li+ exchange between the electrolyte and the electrode, but quantification of this effect has been non-straightforward, and a general relationship between Li+ exchange and CE has not been clearly elucidated to date. Using electrochemical impedance and voltammetry, we report self-consistent Li+ exchange values of native SEIs over a range of relevant electrolytes with CE spanning 78.0% to >99%. CE and its retention at high rates are found to be positively correlated with the rate of SEI Li+ exchange. Additionally, Li+ exchange rates increased during cycling in high-CE electrolytes, in some cases by an order of magnitude to exceed 10 mA/cm2, whereas for low-CE electrolytes they remained low (1 mA/cm2).

The realization of high performance Ni-rich layered cathodes remains a challenge because of the multiple degradation factors that concurrently operate during battery cycling. In particular, depletion of oxygen charge and consequent lattice-oxygen instability at deep charge state accelerate the subsequent chemomechanical degradation mechanisms. Among the proposed methodologies, doping has proven to be effective in enhancing the cathode cycle life by stabilizing the layered structure. Herein, we achieved the electrochemically stabilized Ni-rich LiNi0.92Co0.04Mn0.04O2 through Zr doping, resulting in a 15% increase of the capacity retention after 100 cycles. In-depth investigations are conducted to unveil the effects of Zr doping on the layered cathode, and in particular, the critical role of Zr doping on the lattice oxygen stability is systematically studied. By combining state-of-the-art magnetometer characterization, X-ray analysis, and first-principles calculation, we reveal that Zr doping positively contributes the to lattice oxygen stability by alleviating the oxygen charge loss at deep charge, thereby improving the cathode electrochemical reversibility. Our findings provide an insight into the Zr doping mechanism and help to design Ni-rich layered oxides for future applications.

Although replacing biomass, (e.g., wood chips and pellets), with thinning wood and herbaceous biomass is eco-friendly and economically advantageous, their direct utilization in plant boilers is associated with ash-related challenges, including slagging and fouling. The aim of this study is to determine the effects of ash removal treatment (ashless biomass (ALB)) in the context of solid fuel power plant boilers. Ash was removed via neutralization of metal ions and carboxylic acids contained in the biomass ash. The ash removal rate of K, Na, Cl was indicated by assessing the total biomass before and after ash removal treatment, via XRF analysis. Co-combustion with sub-bituminous coal and ALB-treated biomass was analyzed using a drop tube furnace and revealed that NOx and SOx values converged converge toward an approximate 10 ppm error, whereas the Unburned Carbon (UBC) data did not exhibit a specific trend. Factors associated with slagging and fouling, (capture efficiency (CE), and energy based growth rate (GRE)) were calculated. All biomass samples without pretreatment exhibited V-shaped variation. Conversely, for ashless biomass (ALB) samples, CE and GRE gradually decreased. Thus, the ALB technique may minimize slagging and fouling in a boiler, thus, reducing internal corrosion associated with ash deposition and enhancing the economic operation of boilers.

A MnV2O6/graphene nanocomposite was fabricated through hydrothermal synthesis and high energy milling to introduce it as an efficient OER electrocatalyst. The MnV2O6/graphene nanocomposite with 20 wt% graphene exhibited superior electrocatalytic OER performance with a low overpotential and high stability and durability in 1 M KOH aqueous solution, exhibiting even after 1000 CV cycles.

Objective: To develop a simple and accurate HPLC-DAD method for simultaneous determination, the content of major components: limonin, evodiamine, and rutaecarpine in Evodiae fructus and evaluation the quality of Evodiae fructus sold in markets. Methods: Open column chromatography was used to separate and purify rutaecarpine and evodiamine, the two major alkaloids from Evodiae fructus extract as a laboratory standard. Chromatographic separation was achieved using a Germini C18 column (150 mm × 4.6 mm I.D., 5 µm), detected at 210 nm. The mobile phase consisted of acetonitrile (A), methanol (B), and water (C). The validated method simultaneously determined alkaloid content in 40 batches of samples collected from markets in different regions of Vietnam. Results: In one-step purification, our method yielded 326 mg of rutaecarpine and 128 mg of evodiamine from 3.2 g of crude extract, with purities of 98.9 and 98.5%, respectively. The structures of these compounds were identified using 1H NMR and 13C NMR. There was a significant correlation between alkaloid content and fruit size, with a Spearman correlation coefficient of>0.5 (p

Silicon (Si) is considered to be one of the most promising anode candidates for next-generation lithium-ion batteries because of its high theoretical specific capacity and low discharge potential. However, its poor cyclability, caused by tremendous volume change during cycling, prevents commercial use of the Si anode. Herein, we demonstrate a high-performance Si anode produced via covalent bond formation between a commercially available Si nanopowder and a linear polymeric binder through an esterification reaction. For efficient ester bonding, polyacrylic acid, composed of -COOH groups, is selected as the binder, Si is treated with piranha solution to produce abundant -OH groups on its surface, and sodium hypophosphite is employed as a catalyst. The as-fabricated electrode exhibits excellent high rate capability and long cycle stability, delivering a high capacity of 1500 mA h g

Owing to its high theoretical capacity (3860 mAh/g, over 10 times that of graphite) and its lowest theoretical electrochemical potential (-3.04 V vs SHE), Li metal is an ideal anode material for improving the capacity of rechargeable Li batteries [1]. However, the practical application of the Li anode is severely hindered by its high reactivity with standard electrolyte compositions, which results in limited Coulombic efficiency (CE) in those electrolytes (for instance, 85-90% with 1 M LiPF6 EC:DEC [2]). Strategies to improve CE have focused on electrolyte engineering, including development of highly concentrated electrolytes (HCE) and more recently, local high-concentration electrolytes (LHCE) [3]. A feature shared by these strategies is the promotion of contact-ion pairing, which enhances anion contributions to the solid electrolyte interphase (SEI). Among the best-performing salts are fluorinated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium bis(fluorosulfonyl)imide (LiFSI), which are believed to promote stable inorganic-rich SEIs and correlate with higher CE [4]. A second strategy of interest is to pursue development of additives incorporated at relatively low concentrations (e.g., 2-5 wt%) that can favorably alter the SEI, such as carbonates (e.g., vinylene carbonate (VC) [5] and fluoroethylene carbonate (FEC) [6]), sulfates (e.g., ethylene sulfate (DTD) and 1,3-propanesulfonate (PS) [7]), and borates (e.g., lithium difluoro(oxoalate) borate (LiDFOB) [8] and tris (2,2,2-trifluoroethyl) borate (TTFEB) [9]). An advantage of this strategy is the possibility to ultimately lower reliance on high fluorinated salt concentrations, which are costly and can be corrosive towards the Al current collector, and potentially expand the versatility of available electrolyte frameworks having competitive CE. However, compared to the principles developed for salt and solvent selection in HCE and LHCE, the mechanism behind successful additive activation needs elucidation. In this work, we examined the potential of "FSI-like," neutral sulfonyl/sulfamoyl fluorides (R-SO2F and R-R’-NSO2F, Figure 1) as functional additives for Li cycling, motivated by their structural similarity to the high-performance FSI- anion. The examined baseline electrolytes include high-CE systems consisting of LiFSI dissolved in various solvents: fluoroethylene carbonate (FEC, 1 and 4 M salt), 1,2-dimethoxyethane (DME, 4 M), and dimethyl carbonate (DMC, 6 M). The ability for each additive to coordinate with Li+ was first examined by NMR, with trends rationalized in part by supporting microcalorimetry data on the degree of solvent coordination strength. We relate these to CE and cycling outcomes in each electrolyte. Interestingly, we find that additives have negligible effect on CE in FEC-based electrolytes, whereas significant impacts were observed in DME and DMC. We relate these diverse outcomes to the SEI chemical compositions and gases evolved during galvanostatic cycling, as characterized by X-ray photoelectron spectroscopy (XPS) and gas chromatography (GC), which help to rationalize competitive reactions among solvent, anion, and additive. Unfortunately, additives had a negative-to-neutral impact on CE in these systems. Thus, we finally examined a LiPF6 in carbonate electrolyte, 1 M LiPF6 in EC/DMC (LP40), where we hypothesized that competitive reduction of coordinating additives over problematic carbonate solvent would lead to performance gains. Indeed, significant improvements (up to 94%, compared to baseline 89% over the initial 50 cycles) in CE were observed for two additives, with their structural advantages further discussed. Overall, our findings provide insights into the effects of sulfonyl/sulfamoyl fluoride additive structures on Li metal cyclability and the compositions of baseline electrolytes whose electrochemical cycling stability can be effectively modulated by these additives. Xu, W., et al., Lithium metal anodes for rechargeable batteries. Energy & Environmental Science, 2014.7(2):p.513-537. Genovese, M., et al., Combinatorial methods for improving lithium metal cycling efficiency. Journal of The Electrochemical Society, 2018.165(13):p.A3000. Hobold, G.M., et al., Moving beyond 99.9% Coulombic efficiency for lithium anodes in liquid electrolytes. Nature Energy, 2021.6(10):p.951-960. Suo, L., et al., Fluorine-donating electrolytes enable highly reversible 5-V-class Li metal batteries. Proceedings of the National Academy of Sciences, 2018.115(6):p.1156-1161. Aurbach, D., et al., On the use of vinylene carbonate (VC) as an additive to electrolyte solutions for Li-ion batteries. Electrochimica acta, 2002.47(9):p.1423-1439. Markevich, E., et al., Fluoroethylene carbonate as an important component in electrolyte solutions for high-voltage lithium batteries: role of surface chemistry on the cathode. Langmuir, 2014.30(25):p.7414-7424. Han, B., et al., Poor Stability of Li2CO3 in the Solid Electrolyte Interphase of a Lithium ‐Metal Anode Revealed by Cryo ‐Electron Microscopy. Advanced Materials, 2021.33(22):p.2100404. Liu, J., et al., Lithium difluoro (oxalato) borate as a functional additive for lithium-ion batteries. Electrochemistry communications, 2007.9(3):p.475-479. Ma, Y., et al., Enabling reliable lithium metal batteries by a bifunctional anionic electrolyte additive. Energy Storage Materials, 2018.11:p.197-204. Figure 1. (a) Sulfonyl/sulfamoyl fluoride chemical structures and (b) R-S and S-F bond lengths calculated by density functional theory. Figure 1

It has been widely suggested in literature that a lithium fluoride (LiF)-rich solid electrolyte interphase (SEI) affects Coulombic efficiency (CE) of the Li metal anode used with liquid electrolytes. Yet, the influence of LiF on Li metal deposition has been challenging to examine. Herein, we developed a method to synthesize LiF nanoscale particles with tunable sizes (30–300 nm) on Cu electrodes by electrochemical reduction of fluorinated gases under controlled discharge rates and capacities. The impact of LiF nanoparticles on overpotential and morphology of Li deposition was further studied in a conventional carbonate electrolyte. By cyclic voltammetry, Li plating overpotentials exhibit a clear correlation with the total surface area of LiF particles. Additionally, Li metal deposits (10 μAh cm−2) nucleated under galvanostatic conditions (0.5 mA cm−2) on Cu/LiF showed increasing feature sizes with a lower average LiF particle size and higher coverage of LiF. However, no significant improvement in CE was observed for LiF-coated Cu. Our findings provide evidence that a particle-based mode of SEI fluorination can influence early-stage Li nucleation to a modest degree, and this effect is maximized when LiF is uniformly and densely distributed. However, sparser and larger LiF have vanishing or even detrimental effect on cycling performance.

Alkaloids are distributed in plant kingdom and play important role in protection, germination as well as plant growth stimulants. Most of them are chiral compounds and are clinically administered as the racemic mixture, even though its enantiomers have been known to exert different pharmacological activity. Liquid chromatography using chiral stationary phases (CSP) proved to be an essential tool with a wide range of applications, including analysis of the stereochemistry of natural compounds. This review gives an overview of chiral separation alkaloids that were used in theoretical studies and/or applications in recent years. It shows the possibilities of polysaccharide CSPs have now also been established as the first-choice of chiral phases for enantiomer separation.

A MnV2O6/graphene nanocomposite was fabricated through hydrothermal synthesis and high energy milling to introduce it as an efficient OER electrocatalyst. The MnV2O6/graphene nanocomposite with 20 wt% graphene exhibited superior electrocatalytic OER performance with a low overpotential and high stability and durability in 1 M KOH aqueous solution, exhibiting even after 1000 CV cycles.

To meet the ever growing demand for high energy density and high power density lithium ion batteries, silicon (Si) has been spotlighted as a promising anode material due to its high theoretical specific capacity. However, the practical use of Si anodes is hindered by the large volume change during the lithiation/delithiation process and resultant electrode pulverization. Significant progress has been made using nanostructured Si-based materials, but their low initial coulombic efficiency and low volumetric capacity are undesirable for practical applications. Si microparticles (SiMPs) are considered as an alternative because of low cost, commercial availability, and high tap density. Herein, we introduce a novel concept of in situ formation of a graphene oxide (GO)–polyacrylic acid (PAA) composite cage encapsulating silicon microparticles (SiMPs) as an anode for LIBs. The mechanically robust covalent bond was formed between the carboxylic acid group of the PAA binder and the hydroxyl group of GO through an esterification reaction. The ester bonded GO–PAA cage confined the pulverized SiMPs within and maintained the structural integrity resulting in high coulombic efficiency, excellent capacity retention, and high rate capability. The as-fabricated electrode delivered a high capacity of 2300 mA h g−1 after 200 cycles at a high current density of 1000 mA g−1. Furthermore, stable cycling was achieved with a high Si mass loading (1.98 mA h cm−2 after 500 cycles) and in a full cell (1.45 mA h cm−2 after 100 cycles).

A new P2-type Na0.7(Ni0.6Co0.2Mn0.2)O2 was prepared via co-precipitation and its electrochemical properties as a cathode for sodium ion batteries were compared with those of O3-type Na(Ni0.6Co0.2Mn0.2)O2, focusing on phase stability and cycling performance. The P2-type delivered a high capacity of 108 mA h g-1 after 300 cycles at 2C.

The substitutional solid solution Mn1−xFexP compounds between alloying reaction-type MnP and conversion reaction-type FeP are successfully synthesized via facile high energy mechanical milling and their electrochemical properties as an anode for lithium ion batteries (LIBs) are investigated. A complete solid solution is formed between two end members and the Mn1−xFexP solid solution phosphide electrodes show an enhanced electrochemical performance, delivering a capacity of 360 mA h g−1 after 100 cycles at a high current density of 2 A g−1 when the advantages of the two reaction mechanisms are beneficially combined. These synergistic effects resulted from the in situ generated nanocomposite of the Li–Mn–P alloying element and the Fe nano-network in combination with the surrounding amorphous lithium phosphide, which effectively buffers the accompanying volume variation, hinders the aggregation of the alloying element, and ensures the electron and ion transport.

V4P7 nanoparticles were synthesized via high-energy mechanical milling and their electrochemical properties as an anode for sodium-ion batteries were studied and compared with those of VO2(B)/Na and V4P7/Li cells, focusing on the electrochemical reaction mechanism and cycle performance. The V4P7 showed excellent cycling behavior even without any conductive material.

Linagliptin is a highly specific, long-acting inhibitor that is used as an orally administrable agent for type-2 diabetes treatment. Because only the R-enantiomer is of clinical use, we developed a capillary electrophoresis method for the determination of the enantiomeric impurity of this compound. Carboxymethyl-β-cyclodextrin was selected as the chiral selector for the separation of linagliptin enantiomers. Design of experiments and desirability functions were used for the analytical optimization, which was focused on understanding and improving the electrophoretic process. The effects of significant parameters (background electrolyte concentration and pH, cyclodextrin concentration, temperature, and voltage) were thoroughly investigated. The complete separation of linagliptin and its enantiomeric impurity with baseline resolution was achieved within 10 min on an uncoated fused-silica capillary (50 μm inner diameter, 365 μm outer diameter, 64.5/56 cm in total/ effective length) maintained at 25°C, under an applied voltage of 28.0 kV. The background electrolyte contained 70 mM sodium acetate and 4.7 mM carboxymethyl-β-cyclodextrin, and the pH was adjusted to 6.10. The method was validated, and a limit of quantitation of 0.05% for the impurity was estimated.

The V4P7 phase is synthesized by a facile high energy mechanical milling (HEMM) using vanadium (V) and red phosphorus (P), and its electrochemical properties and reaction mechanism as an anode for lithium ion batteries (LIBs) are investigated. As-synthesized 100 nm-sized V4P7 nanopowder electrode shows the insertion reaction during lithiation/delithiation by forming the amorphous Li-V-P ternary phase and delivers the high discharge and charge capacities of 1035 and 882 mA h g-1, respectively, with a high Coulombic efficiency of 85% at the current density of 100 mA g−1. In addition, V4P7 nanopowder is encapsulated with the conformal carbon layer, which is achieved through polymerization of dopamine and subsequent carbonization. As-fabricated core-shell V4P7@C nanocomposite electrode exhibits the much improved high rate capability and long cycle stability, delivering a high capacity of 388 mA h g-1 after 200 cycles at a high current density of 1 A g−1, which is attributed to high electrical conductivity, high Li+ ion mobility, and structural stability to restrict the aggregation and pulverization of active materials.

A simple, sensitive, and rapid assay based on hydrophilic interaction liquid chromatography (HILIC) with tandem mass spectrometry was developed and validated for the simultaneous determination of metformin and 13 other oral antihyperglycaemic drugs in human urine using metoprolol as an internal standard. A simple sample clean-up procedure using the "dilute and shoot" approach enabled fast and reliable analysis. Chromatographic separation was performed on a HILIC column using an elution gradient of mobile phase A, composed of 1 mM ammonium formate (pH 5), and mobile phase B, composed of acetonitrile, at a flow rate of 0.35 mL/min. Quantitation was performed on a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode by using electrospray ionization in positive ion mode. The total chromatographic run time was 20 min. Calibration curves for each analyte were linear over concentration ranges of 2-300, 5-400, or 20-500 ng/mL, with a coefficient of determination above 0.99. The method was validated for selectivity, sensitivity, recovery, linearity, accuracy and precision, system suitability, robustness, and stability. Inter-batch and intra-batch coefficients of variation across four validation runs were ≤ 13.62%. The present method was successfully applied for the analysis of metformin and nateglinide in urine samples after their oral administration to healthy human subjects under fasted conditions.

Nickel phosphide (NiP2) nanoparticles were prepared via a high energy mechanical milling (HEMM), and their electrochemical properties as an anode for sodium ion batteries (SIBs) were studied. As-synthesized NiP2 was highly agglomerated nanoparticles of 100∼200 nm, which were composed of ∼10 nm nanocrystallites. The NiP2 electrode showed the reversible conversion reaction by forming the Na3P and Ni phases along with unreacted NiP2 and delivered the discharge and charge capacities of 653 and 489 mAh g−1, respectively, with an initial Coulombic efficiency of 75% at a current density of 50 mA g−1. The low reaction potential between Na and NiP2 inhibited the full conversion reaction, which required an activation process. In addition, NiP2/C nanocomposite was fabricated by HEMM using as-synthesized NiP2 and acetylene carbon black. The high resolution transmission electron microscopy (HRTEM) image indicated that the NiP2 nanoparticles were completely covered with ∼10 nm thick carbon layer. The NiP2/C nanocomposite electrode exhibited the improved sodium storage performance and delivered a specific capacity of 428 mAh g−1 after 100 cycles at a current density of 50 mA g-1. The enhanced cycle performance of NiP2/C nanocomposite was attributed to high electrical conductivity, high Na+ ion mobility, and reduction of nanoparticle aggregation during cycling. Furthermore, NiP2/C nanocomposite was successfully operated even at the full cell configuration.

Tin phosphide (Sn4P3) has emerged as an anode for sodium ion batteries (SIBs) due to its high reversible capacity and low redox potential. Sn4P3 shows a synergistic Na-storage reaction to form Na15Sn4 and Na3P, but suffers from large volume expansion and Sn aggregation during the Na+ insertion–extraction resulting in poor cycle stability. Sn4P3 has also been considered a promising anode material for lithium ion batteries (LIBs), but very limited studies have been performed. Herein, core–shell Sn4P3–C (carbon) composite nanospheres are fabricated by carbonization/reduction and phosphorization of SnO2–GCP (glucose-derived, carbon-rich polysaccharide) nanospheres. The size of Sn4P3–C nanospheres is controlled to optimize their electrochemical performance as long-term stable anodes for SIBs and LIBs. Among them, the 140 nm-sized Sn4P3–C nanosphere electrode exhibits high reversible capacity, high rate capability, and ultra-long cycle stability as an anode for both SIBs and LIBs, delivering a high capacity of 420 mA h g−1 after 2000 cycles (SIBs) and 440 mA h g−1 after 500 cycles (LIBs) at a high current density of 2000 mA g−1. Hence, the Sn4P3–C nanospheres can be considered as a promising anode material for next generation SIBs and LIBs.

New red-emitting Eu2+-doped SrLu2O4 phosphors were synthesized by a solid state reaction, and the effects of starting material composition, annealing temperature, and Eu2+ doping concentration on the phase formation and photoluminescence (PL) properties were investigated. A single phase SrLu2O4:Eu2+ phosphor was obtained between 1400 and 1500 °C in Sr-rich condition under 5% H2/N2 atmosphere. As-synthesized SrLu2O4:Eu2+ phosphors exhibited a strong red emission centered at 610 nm under the excitation of λex=450 nm. The highest emission intensity was observed in 0.004 mol Eu-substituted composition, which was ~85% compared to that of commercial (Sr,Ca)AlSiN3:Eu2+ phosphor. SrLu2O4:Eu2+ phosphors showed a strong thermal quenching, which suggests a high potential as an optical temperature sensor.

In attempt to contribute in official monographs of Korean Pharmacopoeia, an HPLC method was developed and fully validated for the determination of tolperisone hydrochloride in tablets which have never been published in other forgein Pharmacopoeia. Analysis was carried out in an ODS column (250 × 4.6 mm I.D., 5 μm) with common solvents include acetonitrile and ammonium hydrophosphate buffer as mobile phase. The assay was validated according to International Conference on Harmonization (ICH) guidelines. The method has good linearity in the range of 5 – 200 μg/mL tolperisone. Intra-day precision varied between 0.04 and 0.10 %. Relative standard deviations of inter-day precision ranged between 0.43 and 1.24 % for peak area. The percentage recovery of the tolperisone ranged between 99.8 and 101.2 % in material. Recoveries in tablets were ranged between 98.7 and 100.8 %, thus confirmed the suitability of method for estimation of tolperisone hydrochloride in tablet dosage form.

Rabeprazole is one of the latest proton-pump inhibitors used for treatment of several gastrointestinal disorders. For therapeutic applications, rabeprazole has been administered as a mixture of R-(+) and S-(-) enantiomers. Owing to pharmacological and toxicological differences between stereoisomers, chiral recognition has now become an integral part of drug research and development. A simple and rapid liquid chromatographic method for enantioselective separation and determination of R-(+) and S-(-) enantiomers of rabeprazole in bulk drug and pharmaceutical formulations was developed. Chiralpak IC (150 × 4.6 mm, 5 μm) column and μmobile phase containing hexane:ethanol:ethylenediamine (30:70:0.05 v/v) in an isocratic mode yielded baseline separation with resolution greater than 6.0 at 35 °C. Effects of additives and n-hexane were evaluated. Optimized condition was validated as per ICH guidelines. The method has good linearity, high sensitivity with LOD was 0.01 μg/mL and LOQ was 0.03 μg/mL for both enantiomers. Intra-day precision varied between 0.44 and 1.79% for S-(-) enantiomer, 0.65 and 1.97% for R-(+) enantiomer. Relative standard deviations of inter-day precision were less than 1.81% for both enantiomers. The percentage recovery for both enantiomers of rabeprazole ranged between 99.81 and 101.95%, 98.82 and 101.36% in material and tablets, respectively. The method was successfully applied to determine content of each enantiomer in commercial tablets.

A high performance liquid chromatographic method was developed and validated for the determination of urazamide in pharmaceutical preparation with novel green aqueous mobile phase modified with room temperature ionic liquids (RTILs). 1-Ethyl-3-methyl-imidazolium tetrafluoroborate ([EMIM][BF4]) was selected as a mobile phase additive to improve retention and avoid baseline disturbances at t0. Various mobile phase parameters such as cation moiety, chaotropic anion moiety, pH and concentration of RTILs were optimized to determine urazamide at the proper retention time. The assay was validated according to International Conference on Harmonization guidelines. The linearity of the calibration curve was good (r2 > 0.999). Intra-day precision varied between 0.50 and 1.23%. Relative standard deviations of inter-day precision ranged between 1.07 and 1.66%. Recoveries in tablets ranged between 99.7 and 101.2% and it was successfully applied to determine urazamide in pharmaceutical preparations.

A new P2-type Na0.7(Ni0.6Co0.2Mn0.2)O2 was prepared via co-precipitation and its electrochemical properties as a cathode for sodium ion batteries were compared with those of O3-type Na(Ni0.6Co0.2Mn0.2)O2, focusing on phase stability and cycling performance. The P2-type delivered a high capacity of 108 mA h g-1 after 300 cycles at 2C.

The substitutional solid solution Mn1-xFexP compounds between alloying reaction-type MnP and conversion reaction-type FeP are successfully synthesized via facile high energy mechanical milling and their electrochemical properties as an anode for lithium ion batteries (LIBs) are investigated. A complete solid solution is formed between two end members and the Mn1-xFexP solid solution phosphide electrodes show an enhanced electrochemical performance, delivering a capacity of 360 mA h g-1 after 100 cycles at a high current density of 2 A g-1 when the advantages of the two reaction mechanisms are beneficially combined. These synergistic effects resulted from the in situ generated nanocomposite of the Li-Mn-P alloying element and the Fe nano-network in combination with the surrounding amorphous lithium phosphide, which effectively buffers the accompanying volume variation, hinders the aggregation of the alloying element, and ensures the electron and ion transport.