Optimal Experimental Conditions Research Articles

High-temperature assisted barium molybdate incorporation into heteroatom-doped porous carbon sheets for selective detection of sulfonamide derivatives

Electrochemical sensors are inherently dependent upon novel electrocatalyst materials with excellent properties. A rapid analytical technique was developed to determine 5-aminosalicylic acid (5-ASA) without the need for time-consuming separation steps. In this study, the perovskite-type barium molybdate (BaMoO3) nanocubes and phosphorous-doped graphitic carbon nitride (P-gC3N5) were prepared by coprecipitation followed the chemical vapour deposition method. Various spectroscopic techniques were performed to analyse the morphology and structure of the proposed electrocatalyst (BaMoO3/P-gC3N5). BaMoO3/P-gC3N5 modified glassy carbon electrodes (GCE) exhibit superior electrocatalytic activity towards 5-ASA detection over unmodified electrodes. Difference Pulse Voltammetry (DPV) was used under optimal experimental conditions for determining 5-ASA accurately. Combining BaMoO3 and P-gC3N5 forms an electrocatalytic hybrid composite with a large specific surface area, rapid electron transfer, and high electrical conductivity. BaMoO3/P-gC3N5 modified electrodes possess a broad detection range (0.01–723 µM), low limit of detection (4.0 nM), excellent selectivity, sensitivity (1.046 µAµM-1cm−2), and good reproducibility toward the detection of 5-ASA. Human serum, urine, and river water samples were successfully tested for 5-ASA content with the electrochemical sensor fabricated.

Simulation and Selection of the Optimal Experimental Conditions to Determine the Low-Energy Parameters of the np Interaction in the nd Breakup Reaction at a Neutron Energy of 5 MeV

Simulation and Selection of the Optimal Experimental Conditions to Determine the Low-Energy Parameters of the np Interaction in the nd Breakup Reaction at a Neutron Energy of 5 MeV

Nanostructured TiO2-X/CuXO-based electrochemical sensor for ultra-sensitive glyphosate detection in real water samples

Glyphosate, a widely employed non-selective pesticide for enhancing crop productivity through weed control, poses significant health and environmental concerns due to its potential link to chronic diseases, cancers, and disruptions in natural symbiotic relationships. Quantifying glyphosate values becomes imperative for effective monitoring and mitigation of associated risks. In response, a novel electrochemical sensor was developed utilizing nanostructured TiO2 films modified with Ti3+ ions and copper oxides for precise detection and quantification of glyphosate in real water samples. The nanotubular structure, synthesized via potentiostatic anodization, underwent further modification through cathodic reduction of Ti4+ to Ti3+ ions and copper electrodeposition. Under optimal experimental conditions, the sensor exhibited a notable ability to detect glyphosate traces by inhibiting peak current in Differential Pulse Voltammetry (DPV). It achieved low limits of detection (LOD = 0.34 pmol/L) and quantification (LOQ = 0.70 pmol/L) within a linear working range of 0.55 to 1000.00 pmol/L. The sensor demonstrated robust stability and excellent precision (repeatability and intermediate precision) without significant variations in analytical response and yielded recovery rates ranging from 91.06 to 99.38 %. These promising results underscore the sensor’s potential application for detecting glyphosate in real aquatic matrices, contributing to effective environmental monitoring and health protection.

Nitrogen-Doped Carbon Dots Enhanced Hydrogen Carbonate-Hydrogen Peroxide Chemiluminescent Reaction and its Application in Ascorbic Acid Sensing.

Nitrogen-doped carbon dots (N-CDs) were prepared by self-exothermic procedure using grasshopper powder as a single precursor. The prepared N-CDs not only have excellent fluorescence properties, but also can catalyze and enhance the ultra-weak chemiluminescence of NaHCO3-H2O2. The reaction conditions of NaHCO3-H2O2-N-CDs CL were optimized. Under the optimal experimental conditions, when AA was added to the NaHCO3-H2O2-N-CDs CL system, AA had a significant inhibitory effect on the CL intensity of NaHCO3-H2O2-N-CDs. There was a good linear relationship between the calculated lg(I0/I) and the concentration of AA (C), and the calibration curve equation was lg(I0/I) = 0.03667C-0.00708 (µM). The established CL analysis method has a detection limit of 0.12 µM for AA and a linear range of 0-50 µM. The selectivity of CL method was evaluated, and the method was successfully applied to the determination of AA in vegetable and fruit samples. The spiked recoveries were between 88.9% and 118.9%, which indicated that the method was simple, rapid, and sensitive, and had great potential in the determination of AA in foods.

Low-temperature fabrication of high-entropy rare earth hexaboride powders

Herein, we report a low-temperature method for synthesizing high-entropy rare earth hexaboride powders by reaction among rare earth oxides, B4C, and Al powders. Al was used as a reducing and decarburization agent in this process, which further reduced the Gibbs free energy change for the reaction of RexOy with B4C to form REB6. By investigating the influence of reacting temperature and amount of Al added on preparation of LaB6, the optimum experimental conditions of this method were determined to be 1300 °C and 2 times the stoichiometric ratio of Al. Theoretical supports were proposed to verify the feasibility for formation of high-entropy borides. Then, multicomponent hexaborides La0.5Ce0.5B6, La0.33Ce0.33Nd0.33B6, and La0.25Ce0.25Nd0.25Sm0.25B6 as well as high-entropy hexaboride La0.2Ce0.2Nd0.2Sm0.2Eu0.2B6 powders were successfully prepared by doping with Ce, Nd, Sm, and Eu on LaB6. RE elements with different radius were uniformly distributed in the multicomponent boride powders without obvious segregation. More importantly, the lattice distortion and stress induced by the element substitution contribute to the reduction of the average powder particle size. Finally, the DTA-TG curves show that rare earth hexaborides have good oxidation resistances when the temperature is below about 1000 °C.

An electrochemical 3D platform using poly (alizarin red S) and magnetite nanoparticles for rapid recognition and determination of tryptophan enantiomers in whole blood samples

The construction of a simple and convenient electrochemical platform for the recognition of enantiomers is crucial for the life sciences and medical fields. Herein, a portable electrochemical 3D platform based on a carbon paste electrode modified (CPE) with poly (alizarin red S) (PARS) and magnetite nanoparticles (Fe3O4NPs) for the recognition and determination of tryptophan enantiomers from whole blood samples was developed. Several methods, including scanning electron microscopy (SEM), differential pulse voltammetry (DPV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), were used to evaluate the morphologies and electrochemical behaviors of the modified electrode. The synthesized magnetite nanoparticles are studied using SEM with energy-dispersive X-ray analysis (EDAX). Under the optimum experimental conditions, the current intensity ratio of d-Trp to l-Trp (ID/IL) was found to be 1.32 at PARS/Fe3O4NPs/CPE, according to the results of differential pulse voltammetry. Furthermore, the developed platform showed a good linear correlation between response current intensity and tryptophan enantiomer concentration, ranging from 0.001 to 0.2 mM. The detection limits for both d-Trp and l-Trp were found to be 0.3 µM. This study demonstrates that the designed platform is capable of rapidly detecting the enantiomeric ratio in a non-racemic tryptophan mixed solution. Finally, the proposed platform was used to identify the Trp enantiomers in human whole blood, confirming the effectiveness of the modified electrode in analyzing real samples. The electrochemical 3D platform is thus used not only to recognize tryptophan enantiomers but also exhibits a significant promise for practical uses.

Zirconia nanoparticles/carbon quantum dots modified carbon paste electrode as electrochemical sensor for determination of antiepileptic drug eslicarbazepine acetate in bulk and pharmaceutical dosage form

A new, sensitive and selective electrochemical method has been developed for determination of the antiepileptic prodrug eslicarbazepine acetate (ESL) that is used for the treatment of partial-onset seizures in adults with epilepsy. It belongs to the class of sodium channel blockers called dibenzoazepine family. A novel modified zirconia nanoparticles carbon paste nanocomposite, carbon dots sensor prepared from banana peels by solvothermal method has been fabricated. The voltammetric method is based on the direct anodic oxidation of ESL at the electrode surface using differential pulse voltammetry. Under the optimum experimental conditions, ESL exhibited a linear relationship in the range of 3.04 × 10-8 to 9.66 × 10-5 M with a lower detection limit of 7.57 × 10-9 M and quantification limit of 2.29 × 10-8 M. The proposed method was validated according to ICH guidelines and was applied for estimating ESL in raw material showing high accuracy and precision with successful application on tablet dosage form.

Enhanced electrochemical detection of nitrite and nitrate in water using Chitosan-Copper phthalocyanine nanocomposite

In this investigation, we study the behavior of a hybrid nanomaterial system combining chitosan-based tetrasulfonated copper phthalocyanine catalyst (Chit/Ts-CuPc) modified carbon screen-printed electrodes (CSPE) for the determination of nitrite and nitrate. Under optimal experimental conditions defined by cyclic voltammetry (CV) and square wave voltammetry (SWV) surveys, the functionalized CSPE exhibited significant catalytic activity towards nitrite and nitrate with a considerable enhancement of the cathodic-anodic peak currents. The Chit/Ts-CuPc nanocomposite enabled the sensors to have a broad linear detection range, which allows quantifying analytes at various concentrations, from 40 to 100 µM for nitrite and 1 to 10 µM for nitrate. Low detection limits (3Sb/m) have been achieved, which are 0.06 µM and 0.05 µM for nitrite and nitrate ions, respectively. Moreover, the proposed modified electrode showed its applicability by measuring the concentration of nitrite and nitrate ions with interfering species and in real water samples.

An ultrasensitive fluorescence sensing platform for HCV detection based on the T7 isothermal amplification combined with aggregation-induced emission luminogens strategy

Hepatitis C virus infection constitutes a significant global public health concern. Fluorescence technique (FL) is a promising biosensor, however, many conventional dyes exhibit reduced fluorescence or no emission at high concentrations. To break through this shackle, an ultrasensitive AIE-based (aggregation-induced emission) FL sensing platform was developed for HCV detection by using the FLRNAs-based T7 isothermal transcription amplification RNA diagnosis combined with AIE luminogens (FTAR) strategy. In the FTAR strategy, the T7 transcription amplification process was responsible for the recognition of the target HCV and produced Pepper aptamer, which could form aggregates of nanoparticles with the HBC, an AIEgen, to produce high-intensity FL. The multi-integrated signal amplification strategy led to ultrasensitivity. Moreover, under the optimal experimental conditions, HCV could be assayed in the range of 100aM-100pM. The proposed strategy has been successfully applied in detecting HCV in clinical samples. In summary, this research was the first to utilize aptamer restriction of AIEgens internal rotation to achieve aggregation-induced emission and presented the successful development of a specific, sensitive and rapid FTAR assay for HCV diagnosis. The proposed FTAR platform with facile operation, short analysis time, low-cost as well as excellent quantification ability could provide a promising tool for point-of-care testing (POCT).

A self-powered photoelectrochemical aptasensor based on target response and Ag-CdIn2S4 photosensitive material for ultrasensitive detection of prostate-specific antigen

In this study, Ag-CdIn2S4 was selected as a photosensitive material and combined with the zeolite imidazole frame-90 encapsulated methylene blue (ZIF-90@MB) to establish a controlled release system. On that basis, a self-powered photoelectrochemical (PEC) aptasensor was constructed based on target responses to realize the highly sensitive detection of prostate-specific antigen (PSA). The self-powered sensing method was employed to effectively avoid interference from other oxidizing/reducing substances in the system and improve the accuracy of the detection method. The band gap of CdIn2S4 was adjusted by Ag doping, and the visible light absorption capacity and photoelectric conversion efficiency of the material were improved by the local surface plasmon resonance (LSPR) effect of metal Ag. The ZIF-90 porous material was used as a carrier, the MB photosensitizer as a signal molecule was loaded in the ZIF-90 pore channel. The PSA aptamer (PApt) was attached to the ZIF-90@MB surface to form a simple biological gate. In the presence of the PSA, the recognition interaction between PApt and PSA made the biological gate open, then many MB molecules were released from ZIF-90 and enhanced the photocurrent signal. Under the optimal experimental conditions, the linear range of the sensor was 0.005 ∼ 50 ng mL−1, and the detection limit was 2.35 pg mL−1. The accurate determination of PSA in human serum was achieved, which provided a novel sensing strategy for the early diagnosis of clinical biomarkers.

Co-Extraction of Aluminum and Silicon and Kinetics Analysis in Carbochlorination Process of Low-Grade Bauxite.

Addressing the issue that the Bayer process is not suitable for low-grade bauxite, carbochlorination was proposed to recover aluminum and silicon from low-grade bauxite. This study focused on the behavior of aluminum and silicon during the carbochlorination process of low-grade bauxite. The impact of various process parameters on the chlorination efficiency was investigated, and the chlorination mechanism and kinetics of aluminum and silicon chlorination in bauxite were analyzed and discussed. Under optimal experimental conditions, the chlorination efficiency of Al2O3 and SiO2 reached 94.93% and 86.32%, respectively. The carbochlorination of aluminum and silicon in bauxite adhered to a shrinking, unreacted core model governed by gas diffusion within the product layer. This process can be bifurcated into two stages. Additionally, calculations were conducted to determine the apparent activation energy and reaction order of the chlorination processes involving Al2O3 and SiO2. Examining the chlorination mechanism revealed that the bauxite carbochlorination encompasses transformations among various minerals. Notably, the aluminum component prefers to participate in the carbothermal chlorination reaction over silicon.

Adsorption of β-Lactoglobulin on Thiol-Functionalized Mesoporous Silica.

SBA-15 mesoporous materials were synthesized with different pore sizes (5 and 10 nm) and thiol-functionalized groups and then characterized to describe their ability to differentially adsorb β-lactoglobulin (BLG), a globular protein with an ellipsoid shape measuring 6.9 nm in length and 3.6 nm in width. All adsorption experiments showed that the adsorption capacities of mesoporous materials for BLG were dependent on the duration of contact between the two materials (mesoporous material and BLG) and the initial BLG concentration. It was also shown that the pore sizes and thiol groups of SBA-15-based adsorbents are important factors for the BLG adsorption capacities. Among the tested adsorbents, thiol-functionalized SBA-15 with a 10 nm pore size (SBA-15-SH-10) showed the highest adsorption capacity (0.560 g·g-1) under optimal experimental conditions. Kinetics studies demonstrated that the adsorption occurs predominantly inside the pores, with interactions occurring on heterogeneous surfaces. In addition, the thermodynamic parameters indicate a spontaneous and exothermic behavior of the BLG adsorption process onto the thiol-functionalized SBA-15 mesoporous adsorbent. Finally, the characterization of the SBA-15-SH-10 adsorbent at 308 K showed the occurrence of an oxidation reaction of the thiol groups to sulfonate groups during the adsorption process as confirmed by Raman spectroscopy. The spectra recorded after adsorption of the protein showed that this adsorption did not affect the secondary structure of the protein.

Deep Eutectic Solvents-Based Ultrasonic-Assisted Dispersive Liquid-Liquid Microextraction for the Determination of Organophosphorus Pesticides in Honeysuckle Dew Samples.

A deep eutectic solvent (DES) with the ability to change from hydrophilic to hydrophobic was designed and synthesized and applied to the determination of organophosphorus (OPP) pesticides in honeysuckle dew samples. Choline chloride, phenol, and tetrahydrofuran (THF) were used as the hydrogen bond acceptor, hydrogen bond donor, and demulsifier, respectively. Eight OPP pesticides were extracted by DES coupled with ultrasonic-assisted extraction (UA) and then chromatographed by GC-MS. DES used as an extract solvent has the advantages of high extraction efficiency, low cost, and environmental protection. Furthermore, DES is compatible with GC-MS. The single factor experiment design and Box-Behnken design (BBD) were applied to the optimization of experimental factors, including the type and composition of extraction solvent, type of demulsifier solvent, the volume of DES and THF, pH of sample solution, and ultrasonic time. Under the optimum experimental conditions, the high degree of linearity from 0.1 to 20.0 ng mL-1 (R2 ≥ 0.9989), the limits of detection from 0.014 to 0.051 ng mL-1 (S/N = 3), and the recoveries of analytes from 81.4 to 104.4% with relative standard deviation below 8.6%. In addition, the adsorption mechanism of OPPs on DES was explored by adsorption kinetic studies. These results have demonstrated that the present method has offered an effective, accurate, and sensitive methodology for OPP pesticides in honeysuckle dew samples, and this method provides a reference for the detection of pesticide residues in traditional Chinese medicine.

Preparation of g-C3N4/NS-CQDs composites and their application in the detection of hydrogen peroxide and glucose

Based on the excellent properties of g-C3N4, co-doped carbon quantum dots (NS-CQDs) were selected to modify it in order to enhance its peroxidase-like activity, and the synthesized NS-CQDs/g-C3N4 nano-enzymes were applied to the detection of common small molecules, such as hydrogen peroxide and glucose, to provide theoretical basis for the construction of g-C3N4 nano-enzymes-based biosensors. FT-IR, SEM, TEM, and other characterization methods determined the composition and morphology of NS-CQDs/g-C3N4. This paper discusses the influence of different morphologies on composites’ catalytic activity. According to the fluorescence spectrum, thecatalytic mechanismfollowsthe hydroxyl radicalmechanism. Under the optimal experimental conditions, the prepared composites were used to detect glucose, and the resultant detection limit of glucose was 1.63 μΜ. The results showed that NS-CQDs/g-C3N4 outperforms most of the nanoenzymes of similar materials, which provides a new idea to broaden its application in nanoenzymes.

Thermal effects and biological response of breast and pancreatic cancer cells undergoing gold nanorod-assisted photothermal therapy

To increase the therapeutic efficacy of nanoparticle (NP)-assisted photothermal therapy (PTT) and allow for a transition toward the clinical setting, it is pivotal to characterize the thermal effect induced in cancer cells and correlate it with the cell biological response, namely cell viability and cell death pathways. This study quantitatively evaluated the effects of gold nanorod (GNR)-assisted near-infrared (NIR) PTT on two different cancer cell lines, the 4T1 triple-negative breast cancer cells and the Pan02 pancreatic cancer cells. The interaction between nanomaterials and biological matrices was investigated in terms of GNR internalization and effect on cell viability at different GNR concentrations. GNR-mediated PTT was executed on both cell lines, at the same treatment settings to allow a straightforward comparison, and real-time monitored through thermographic imaging. A thermal analysis based on various parameters (i.e., maximum absolute temperature, maximum temperature change, temperature variation profile, area under the time-temperature change curve, effective thermal enhancement (ETE), and time constants) was performed to evaluate the treatment thermal outcome. While GNR treatment and NIR laser irradiation alone did not cause cell toxicity in the selected settings, their combination induced a significant reduction of cell viability in both cell lines. At the optimal experimental condition (i.e., 6 μg/mL of GNRs and 4.5 W/cm2 laser power density), GNR-assisted PTT reduced the cell viability of 4T1 and Pan02 cells by 94% and 87% and it was associated with maximum temperature changes of 25 °C and 29 °C (i.e., ∼1.8-fold increase compared to the laser-only condition), maximum absolute temperatures of 55 °C and 54 °C, and ETE values of 78% and 81%, for 4T1 and Pan02 cells, correspondingly. Also, the increase in the GNR concentration led to a decrease in the time constants, denoting faster heating kinetics upon irradiation. Furthermore, the thermal analysis parameters were correlated with the extent of cell death. Twelve hours after NIR exposure, GNR-assisted PTT was found to mainly trigger secondary apoptosis in both cell lines. The proposed study provides relevant insights into the relationship between temperature history and biological responses in the context of PTT. The findings contribute to the development of a universal methodology for evaluating thermal sensitivity upon NP-assisted PTT on different cell types and lay the groundwork for future translational studies.

Two‐Dimensional Copper‐Based Metal‐Organic Framework for Efficient Removal of Methylene Blue from Wastewater

AbstractMetal‐organic frameworks (MOFs) can effectively remove methylene blue (MB) from wastewater due to their abundant adsorption sites and multi‐level pores. In this paper, a copper‐based MOF: {[Cu ⋅ (L) ⋅ (H2O)] ⋅ (DMF)}n (1) (H2L=2‐hydroxyterephthalic acid; DMF=N,N‐dimethylformamide), was synthesized by hydrothermal synthesis method. X‐ray single crystal diffraction showed that a two‐dimensional structure was formed by the carboxyl group of L2− in 1 took μ2‐η1 : η1 bridged two adjacent Cu(II). In this two‐dimensional structure, the coordinated water molecules and hydroxyl group on L2− were distributed on the surface of 1. Thus, it had abundant adsorption sites. The transmission electron microscopy (TEM) of copper‐based MOF nano adsorbent showed that the particle diameter of the nano adsorbent prepared by a cell fragmentation apparatus was about 50 nm. The performance of the copper‐based MOF nano adsorbent in adsorbing MB indicated that the optimal adsorbent dosage was 0.20 g/L and the solution pH was 6. Under the optimal experimental conditions, its maximum adsorption capacity for MB was 143.3 mg/g, which was superior to most MOFs adsorbents. The adsorption thermodynamic analysis showed that the copper‐based MOF nano adsorbent at 25–45 °C was an exothermic (ΔH<0), and spontaneous (ΔG<0) process.

Studies on Sorption and Release of Doxycycline Hydrochloride from Zwitterionic Microparticles with Carboxybetaine Moieties.

The aim of this study was to examine the use of zwitterionic microparticles as new and efficient macromolecular supports for the sorption of an antibiotic (doxycycline hydrochloride, DCH) from aqueous solution. The effect of relevant process parameters of sorption, like dosage of microparticles, pH value, contact time, the initial concentration of drug and temperature, was evaluated to obtain the optimal experimental conditions. The sorption kinetics were investigated using Lagergren, Ho, Elovich and Weber-Morris models, respectively. The sorption efficiency was characterized by applying the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The calculated thermodynamic parameters (ΔH, ΔS and ΔG) show that the sorption of doxycycline hydrochloride onto zwitterionic microparticles is endothermic, spontaneous and favorable at higher temperatures. The maximum identified sorption capacity value is 157.860 mg/g at 308 K. The Higuchi, Korsmeyer-Peppas, Baker-Lonsdale and Kopcha models are used to describe the release studies. In vitro release studies show that the release mechanism of doxycycline hydrochloride from zwitterionic microparticles is predominantly anomalous or non-Fickian diffusion. This study could provide the opportunity to expand the use of these new zwitterionic structures in medicine and water purification.

Aptamer and sodium alginate decorated graphene oxide composite material with ion responsiveness for Low-density lipoprotein trapping

The accumulation of excess Low-density lipoprotein (LDL) is strongly associated with the occurrence of heart failure, coronary artery disease and hypercholesterolaemia, and is a major factor in cardiovascular and cerebrovascular disease. Concerns about the ways to decrease LDL level have continuously arisen. In this study, an ionic stimulation-responsive composite (i.e., GO@Apt@SA) is prepared with modification of graphene oxide (GO) utilising LDL-aptamer (Apt) and sodium alginate (SA). The ion-responsive behaviour of GO@Apt@SA synergistically interacts with the specific recognition property of the aptamer, enabling adsorption of LDL with higher capacity and specificity. Under the optimal experimental conditions, the maximum adsorption capacity of GO@Apt@SA for LDL is 730.6 μg mg−1. Interestingly, the aptamer complementary chain could trigger the release of LDL with favourable elution efficiency, which competitively binds with LDL-specific aptamer to trigger LDL release. More importantly, GO@Apt@SA exhibits satisfactory adsorption performances for LDL in goat serum, meaning that the composite material and technology are available for the extraction of LDL from complex sample matrices.

Multi-functional nanozyme-based colorimetric, fluorescence dual-mode assay for Salmonella typhimurium detection in milk.

Rapid and high-sensitive Salmonella detection in milk is important for preventing foodborne disease eruption. To overcome the influence of the complex ingredients in milk on the sensitive detection of Salmonella, a dual-signal reporter red fluorescence nanosphere (RNs)-Pt was designed by combining RNs and Pt nanoparticles. After being equipped with antibodies, the immune RNs-Pt (IRNs-Pt) provide an ultra-strong fluorescence signal when excited by UV light. With the assistance of the H2O2/TMB system, a visible color change appeared that was attributed to the strong peroxidase-like catalytic activity derived from Pt nanoparticles. The IRNs-Pt in conjunction with immune magnetic beads can realize that Salmonella typhimurium (S. typhi) was captured, labeled, and separated effectively from untreated reduced-fat pure milk samples. Under the optimal experimental conditions, with the assay, as low as 50 CFU S. typhi can be converted to detectable fluorescence and absorbance signals within 2 h, suggesting the feasibility of practical application of the assay. Meanwhile, dual-signal modes of quantitative detection were realized. For fluorescence signal detection(emission at 615 nm), the linear correlation between signal intensity and the concentration of S. typhi was Y = 83C-3321 (R2 = 0.9941), ranging from 103 to 105 CFU/mL, while for colorimetric detection(absorbamce at 450 nm), the relationship between signal intensity and the concentration of S. typhi was Y = 2.9logC-10.2 (R2 = 0.9875), ranging from 5 × 103 to 105 CFU/mL. For suspect food contamination by foodborne pathogens, this dual-mode signal readout assay is promising for achieving the aim of convenient preliminary screening and accurate quantification simultaneously.

Cu2S/Ni3S2 nanosheets combined with nickel foam substrate for efficient catalytic ozonation of p-nitrophenol in wastewater

Cu2S/Ni3S2@NF catalyst was prepared by hydrothermal method, and the catalytic ozonation of PNP solution (100 mg/L) was carried out. The removal rate of PNP under optimal experimental conditions was 99.9 % in 40 minutes, which was a significant increase over other systems. ESR revealed that singlet oxygen and superoxide radicals were the primary active ingredients. After the catalyst was used for five times, the catalytic activity remained basically unchanged. The possible degradation pathway and mechanism of Cu2S/Ni3S2@NF catalytic ozonation of PNP were proposed by gas chromatography-mass spectrometry. In real wastewater samples with complex compositions, the Cu2S/Ni3S2@NF/O3 system also achieved efficient degradation. The mechanism and possible pathway of Cu2S/Ni3S2@NF catalytic ozonation of PNP were proposed. This study provides an efficient, durable, and easy-to-recycle ozone catalyst, which provides a feasible pathway for the treatment of phenolic pollutants.