Colloidal Surface Active Maghemite Nanoparticles for Biologically Safe CrVI Remediation: from Core‐Shell Nanostructures to Pilot Plant Development

The present study is aimed at the exploration of achievable improvements for Cr^VI ex situ and in situ water remediation by using novel naked colloidal maghemite (γ‐Fe₂O₃) nanoparticles (surface active maghemite nanoparticles, SAMNs). The reliability of SAMNs for Cr^VI binding and removal was demonstrated, and SAMN@Cr^VI complex was characterized, as well as the covalent nature of the absorption was unequivocally proved. SAMNs were structurally and magnetically well conserved after Cr^VI binding. Thus, in consideration of their affinity for Cr^VI, SAMNs were exploited in a biological model system, mimicking a real in situ application. The assay evidenced a progressive reduction of revertant colonies of Salmonella typhimurium TA100 strain, as maghemite nanoparticles concentration increased, till the complete suppression of Cr^VI mutagen effect. Finally, an automatic modular pilot system for continuous magnetic removal and recovery of Cr^VI from water is proposed. SAMNs, thanks to their colloidal, binding, and catalytic properties, represent a promising tool as a reliable nanomaterial for water remediation by Cr^VI.     

Fast simultaneous LC/MS/MS determination of 10 active compounds in human serum for therapeutic drug monitoring in psychiatric medication

A UPLC/MS/MS method with simple protein precipitation has been validated for the fast simultaneous analysis of agomelatine, asenapine, amisulpride, iloperidone, zotepine, melperone, ziprasidone, vilazodone, aripiprazole and its metabolite dehydro‐aripiprazole in human serum. Alprenolol was applied as an internal standard. A BEH C₁₈ (2.1 × 50 mm, 1.7 µm) column provided chromatographic separation of analytes using a binary mobile phase gradient (A, 2 mmol/L ammonium acetate, 0.1% formic acid in 5% acetonitrile, v/v/v; B, 2 mmol/L ammonium acetate, 0.1% formic acid in 95% acetonitrile, v/v/v). Mass spectrometric detection was performed in the positive electrospray ionization mode and ion suppression owing to matrix effects was evaluated. The validation criteria were determined: linearity, precision, accuracy, recovery, limit of detection, limit of quantification, reproducibility and matrix effect. The concentration range was as follows: 0.25–1000 ng/mL for agomelatine; 0.25–100 ng/mL for asenapine and iloperidone; 2.5–1000 ng/mL for amisulpride, aripiprazole, vilazodone and zotepine; 2.3–924.6 ng/mL for dehydroaripiprazole; 2.2–878.4 ng/mL for melperone; and 2.2–883.5 ng/mL for ziprasidone. Limits of quantitation below a therapeutic reference range were achieved for all analytes. Intra‐run precision of 0.4–5.5 %, inter‐run precision of 0.6–8.2% and overall recovery of 87.9–114.1% were obtained. The validated method was successfully implemented into routine practice for therapeutic drug monitoring in our hospital. Copyright © 2015 John Wiley & Sons, Ltd.     

Determination of the Dominant Species and Reactions in Non-equilibrium CO<Subscript>2</Subscript> Thermal Plasmas with a Two-Temperature Chemical Kinetic Model

It has become increasingly clear that deviations from local thermodynamic equilibrium occur in thermal plasmas. This paper is devoted to investigating the non-equilibrium characteristics of CO₂ thermal plasmas, which have wide application in industry. A two-temperature chemical kinetic model with a comprehensive chemical system is developed to calculate the non-equilibrium characteristics of CO₂ thermal plasmas for a wide temperature range, from 12,000 to 500 K, at atmospheric pressure. The non-equilibrium results are compared to the equilibrium composition obtained by Gibbs free energy minimization, and significant deviations are found at lower temperatures. Based on the dependence of molar fractions on temperature, the dominant species are determined in three temperature ranges. The dominant reactions are then obtained by considering their contribution to the generation and loss of the dominant species. Using the dominant species and reactions, the full model is simplified into three simpler models and the accuracy of the simplified models is evaluated. It is shown that this approach greatly reduces the number of species and reactions considered, while showing good agreement with the full model, with a root-mean-square error of no more than 4 %. Thus, the complicated physicochemical processes in non-equilibrium CO₂ thermal plasmas can be characterized by relatively few species and reactions. It is suggested that the two-temperature chemical kinetic model developed in this paper can be applied to the full range of pressures that occur in arc welding, arc quenching and other industrial applications. In addition, the simplified methods can be applied in multi-dimensional models to reduce the chemical complexity and computing time while capturing the main physicochemical processes in non-equilibrium CO₂ thermal plasmas.     

Plasma Induced Graft Polymerization of Three Hydrophilic Monomers on Nylon 6,6 Fabrics for Enhancing Antistatic Property

In this study, three hydrophilic monomers; 2-acrylamido-2-methyl-1-propanesulfonic acid, 2-hydroxyethyl methacrylate, diallyldimethylammonium chloride (DADMAC) were selected and their performance as an antistatic finish on nylon 6,6 fabrics was investigated. A non-thermal, high density atmospheric pressure plasma was used to graft polymerize the monomers on nylon 6,6 fabrics. Fabrics were first treated with solutions of monomer in water, air dried and then treated with helium plasma to graft polymerize the monomer on the fiber surface. Surface resistivity values were measured before and after soxhlet extraction with water. Results showed that the DADMAC monomer provided better antistatic properties to fabrics. Further studies with DADMAC monomer were made; effects of plasma post exposure time, plasma pre-exposure time, plasma power, concentration of the monomer and existence of a crosslinker were investigated. Higher plasma power, higher concentration of the monomer and longer post exposure times all gave better antistatic properties to the nylon 6,6 fabrics. Acid dye staining, UV–Vis and FT-IR measurements were conducted and results confirmed a grafted poly-DADMAC layer on the fabric surface.     

Trichloroethylene Combustion in a Submerged Thermal Plasma: Results and Chemical Kinetics Model

This work deals with incineration of organic liquid wastes using an oxygen thermal plasma jet, submerged in water. The results presented here concern incineration of trichloroethylene (TCE). During a trial run, the CO₂ and CO content in the exhaust gas is continuously measured; samples taken periodically from the solution are analyzed by appropriate methods: total organic carbon and chlorine content are measured. Process efficiency during tests with a few L/h of TCE is given by the mineralization rate. The trapping rate of chlorine as HCl is near 100 %. The TCE destruction and removal efficiency, measured by MS/GC, is better than 99.9999 %. A simplified kinetic model of gas quenching was constructed from a single-phase plug-flow reactor model taking into account 14 species and 34 reactions. It satisfies the requirements of heat balance and major components analysis, and reveals the major role of the OH radical on the concentrations of CO as well as HCl and/or Cl₂ in the off-gas stream.     

Low Temperature Diesel Particulate Filter Regeneration by Atmospheric Air Non-thermal Plasma Injection System

An experimental study of the regeneration of diesel particulate filter (DPF) was conducted through the use of a self-designed Non-thermal plasma (NTP) injection system with an experimental temperature of 20–300 °C, with atmospheric air being used as the gas source. The results revealed that the PM could be broken down into CO and CO₂ by NTP, through a discharge reaction of the NTP reactor. As the temperature increases, the mass of C₁ (mass of C in CO) showed an overall declining trend. Interestingly, the mass of C₂ (mass of C in CO₂) and C₁₂ (the sum of C₁ and C₂) both showed an initial increase, followed by a decrease. The peak mass of C₁₂ appears at 150 °C, and both axial and radial temperature gradients are less than the limit of DPF temperature gradient at this temperature. In conclusion, DPF can be regenerated by the NTP technology at a lower temperature, which can aid in the avoidance of thermal damage of DPF. The technology boasts a great advantage in adopting atmospheric air as its gas source, which can not only reduce costs, but also is convenient.     

Advanced Sensing of Antibiotics with Magnetic Gold Nanocomposite: Electrochemical Detection of Chloramphenicol

The sensing and accurate determination of antibiotics in various environments represents a big challenge, mainly owing to their widespread use in medicine, veterinary practice, and other fields. Therefore, a new, simple electrochemical sensor for the detection of antibiotic chloramphenicol (CAP) has been developed in this work. The amplification strategy of the sensor is based on the application of magnetite nanostructures stabilized with carboxymethyl cellulose (Fe₃O₄‐CMC) and decorated with nanometer‐sized Au nanoparticles (NPs) (Fe₃O₄‐CMC@Au). In this case, CMC serves as a stabilizing agent, preventing the aggregation of Fe₃O₄ NPs, and hence, enabling the kinetic barrier for electron transport to be overcome, and the Au NPs serve as an electron‐conducting tunnel for better electron transport. As a proof of concept, the developed nanosensor is used for the detection of CAP in human urine samples, giving a recovery value of around 97 %, which indicates the high accuracy of the as‐prepared nanosensor.     

Analytical performance of glucometers in a tertiary care hospital

Point-of-care (POC) testing of glucose (glucometers) represents a convenient alternative to monitor glycemia since the measurement procedure is performed without delay after sampling of the capillary blood, thereby avoiding the metabolism by the blood cells of glucose present in plasma. Likely because of sample instability, there is no proficiency test provider in Brazil for this type of POC sample. In this context, this study aimed to evaluate the analytical performance of glucometers used in a tertiary care hospital. The glucometers used were the Accu-Chek Performa^® model from Roche Diagnostics, which use the principle of amperometry. The reference method was the reaction with modified hexokinase/glucose-6-phosphate in a Dimension^® device. The stability evaluation of the control samples showed that it can be performed up to 90 min after the collection of whole blood samples. In the two rounds performed, only one result of the 17 glucometers evaluated was out of the threshold of two standard deviation. Thus, this method for control of glucometers met the expectations and enabled comparing the glucometers in a hospital. Given the current quality guidelines, daily internal quality control of glucometers is recommended, besides at least two annual comparisons between the results of the glucometers and the reference method and one EQA every 3 months.