As a result of their growing use, platinum nanoparticles (PtNPs) can pollute different environmental compartments, especially road dust due to their application in vehicle catalytic converters. Their ...presence in these matrices should be controlled to achieve adequate environmental risk assessment, but there is a lack of standardized analytical methods for this purpose. Therefore, this study describes the development and analytical characterization of a rapid sample preparation strategy for the analysis of PtNPs in road dust by single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). Parameters within the critical steps of the extraction (such as the type of energy, sample-to-reagent ratio, intensity, or time), and subsequent phase separation have been optimized using a road dust reference material (BCR-723, certified for total Pt), and spiked road dust samples. The final method consists of a sonication probe assisted extraction, using water as extractant, followed by a separation based on centrifugation, and dilution prior to SP-ICP-MS. Information about size and both mass- and particle-based concentration is provided in <11 min. A recovery rate of 100 ± 1% is achieved in the spiked road dust samples, and a 12 ± 1% (n = 6) of the total Pt was found to be as PtNPs in the certified reference material. The applicability of this methodology has been proven performing the analysis of PtNPs in real road dust samples, with sizes between 15 and 75 nm, and concentrations (6.0–20.0 ng g−1) that represents from 11 to 27% of the Pt content.
Display omitted
•An ultrasonic probe-assisted extraction has been optimized for PtNPs in road dust.•The phase separation required after the extraction was a critical step.•Concentration and particle size distribution of PtNPs have been determined by SP-ICP-MS.•The method has been successfully applied to a reference material and real road dust samples.•Results are of interest for the standardization of quantitative methods for other NPs.
A novel method of ultrasonic probe-assisted ionic liquid dispersive liquid–liquid microextraction combined with electrothermal atomic absorption spectrometry (ETAAS) was developed for the ...determination of chromium(VI) species in water samples. In this procedure, the hydrophobic chelate of chromium(VI) with ammonium pyrrolidinedithiocarbamate (APDC) was extracted into the fine droplets of 1-hexyl-3-methylimidazolium hexafluorophosphate (HmimPF
6), which was dispersed into the aqueous sample solution by ultrasonication using an ultrasonic probe. Several variables such as the volume of HmimPF
6, sample pH, concentration of APDC, and extraction time were investigated in detail. Under the optimum conditions, the limit of detection of the proposed method was 0.07
ng
mL
−1 for Cr(VI) and the relative standard deviation for five-replicated determination of 2.0
ng
mL
−1 Cr(VI) was 9.2%. The proposed method has been also successfully applied to the determination of chromium(VI) species in lake and tap water samples.
Display omitted
•Ni2P2O7 prepared using ultrasonic probe supported chemical precipitation approach.•The XRD, FTIR, FESEM and EDS employed to study the active material.•The electrochemical analysis ...was studied in 2 M KOH electrolyte −0.2 to 0.8 V window.•The significant specific capacitance (514.7F/g at 1 mV/s) was achieved.•Excellent capacity retention (80% retention over 3000 cycles).
New materials and synthesis strategies are needed to achieve better electrochemical performance. In this context, we developed a Ni2P2O7 Nanosheets (NNS) as a new classical-type active electrode using a simple and low-cost method. Crystal phase, chemical structure, and morphology of the sample were inspected by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (FESEM) - Energy Dispersive Spectroscopy (EDS) analysis, respectively. As prepared electrode material was confirmed with monoclinic phase and nanosheet morphology identified from XRD and FESEM analysis, respectively. Various types of electrochemical approaches, such as CV, GCD, Cycling stability, and EIS applied in 2 M KOH electrolytes to investigate supercapacitive behaviour. As fabricated electrode material portrays satisfied specific capacitance (Cs) of 514.7F/g at a scan rate of 1 mV/s along with the excellent cyclic ability of 80 % retention upon 3000 continuous CV cycles, good rate capability in the extended potential window of 1 V. The GCD tests revealed remarkable specific capacity (462C/g) and exceptional energy density (64 Wh/Kg). Moreover, electrode material displayed impressive columbic efficiency as to be 77 % and 51 % at lower and higher current densities, respectively. These notable merits suggest that our designed Nanosheets (NNS) sample is the best opportunity for the development of sustainable supercapacitor devices.
Deep eutectic solvents (DESs) are receiving increased attention from researchers in many areas of science and technology. During the actual operation, the high viscosity of DESs, especially for ...solid-phase sample application, can be diminished by combination of water in the solvent system, heating, and consuming a large volume of DESs. In addition, plant matrix properties of Schisandra chinensis Baill fruits should be considered including sugars-rich and full of stone cells, which also dissolve into the solvent and to reduce extraction capacity. In this study, an ultrasonic probe-based system with a direct delivery of ultrasound to sample was developed to help the matrix materials become hydrated and swelled, which increases the diffusion and flow of solvent into the dry matrix and increases mass transfer, and also minish ultrasonic energy loss. Some parameters that potentially influence circulating and pulsating ultrasonic probe extraction (CPUPE) were methodically examined and improved using the Plackett–Burman, Box–Behnken design, and the optimum practical parameters were as follows: water content of DES, 20.2%; liquid-to-solid ratio, 11.0 mL/g; total ultrasonic treatment time, 24.7 min; ultrasonic setting temperature, 323 K; ultrasonic irradiation power, 90 W; and circulating rate, 25 mL/min. CPUPE provided a accessibility to use substituted green solvents of DESs (choline chloride-lactic acid) by improving their extraction performance. The high sample extraction capacity and circulation function of the suggested CPUPE technique makes it a quick and effective method for complex substrate plant samples. Under the circulating system, the osmotic pressure difference of the solvent is significantly increased. The CPUPE make the kind method operation simple, fast, can be apply in the on-line production analysis.
Display omitted
•CPUPE is suitable for high viscosity solvent, especially for DES.•CPUPE overcomes many problems brought from DES aqueous solution.•CPUPE effectively guarantee big sample amounts for ultrasonic probe application.•CPUPE promote solvent infiltration ability for the high-efficiency extraction.•CPUPE effectively guarantees the quality and yield of lignans.
•Ultrasound (USN) bath and probe influenced chemical composition of young red wine.•Mild USN conditions affected less phenolic, color and aroma.•USN bath (37–80 kHz/20–60 °C/40–100%) with highest ...impact on chemical composition.•USN probe (12.7–25.4 mm/3–9 min/25–100%) had the most important effect.•High power USN influenced wine phenolic composition after 6 months of storage in bottles.
In this study, the effects of both ultrasonic bath and probe treatments on the phenolic, chromatic and aroma composition of young red wine Cabernet Sauvignon were studied and modeled by artificial neural networks (ANNs). Moreover, the effect of high power ultrasound (HPU) along with antioxidants addition (sulfur dioxide and glutathione) was investigated during 6 months of aging in bottles. Lower amplitude and temperature, shorter treatment duration and particularly lower frequency showed a more favorable and milder effect on the chemical composition of wine. In the case of the ultrasonic probe treatment, similar effect was achieved primarily by a larger probe diameter as well as lower amplitude and treatment duration. Selected ANN models showed the best predictions for the chromatic characteristics followed by total phenolics and anthocyanins. The changes induced by HPU treatment after 6 months of aging were mainly detected in the composition of phenolic compounds (both total and individual), where higher concentration of antioxidants (sulfur dioxide and glutathione) slowed down the decrease rate of these compounds during aging. However, HPU treatment did not influence most of the chromatic characteristics and aroma compounds, except lightness and fatty acids. The obtained results indicated that suitable ultrasound treatment might accelerate some aging reactions and shorten the period of wine aging.
Phenolic acids of oak gall were extracted using ultrasonic-probe assisted extraction (UPAE) method in the presence of ionic liquid. It was compared with classical ultrasonic-bath assisted extraction ...(CUBAE) and conventional aqueous extraction (CAE) method, with and without the presence of ionic liquid. Remarkably, the UPAE method yielded two-fold higher extraction yield with the presence of ionic liquid, resulting 481.04 mg/g for gallic acids (GA) and 2287.90 mg/g for tannic acids (TA), while a decreased value of 130.36 mg/g for GA and 1556.26 mg/g for TA were resulted with the absence of ionic liquid. Intensification process resulted the highest yield of 497.34 mg/g and 2430.48 mg/g for GA and TA, respectively, extracted at temperature 50 °C with sonication intensity of 8.66 W/cm
and 10% duty cycle, diluted in ionic liquid, 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, BmimTf
N at concentration of 0.10 M with sample-to-solvent ratio 1:10 for 8 h. Peleg's model successfully predicted the UPAE process confirming that extraction capacity is the controlling factor in extracting phenolic acids. Hence, it can be concluded that UPAE method and ionic liquid have synergistic effect as it effectively enhanced the extraction efficiency to increase the bioactive constituents yield.
A method based on single-particle inductively coupled plasma mass spectrometry (sp-ICPMS) using a dwell time 50 μs for acquisition has been developed for silver nanoparticles (Ag NPs) determination ...and characterization in bivalve molluscs. Ultrasound assisted enzymatic hydrolysis has been proposed for a fast isolation of Ag NPs from seafood using pancreatin and lipase as extracting enzymes. Optimum extraction conditions imply ultrasonication at 80% amplitude for 10 min, using 10 mL of enzymatic solution (2 g L−1/2 g L−1 pancreatin:lipase, pH 7.4). Repeatability of the over-all procedure was 8%, and the limit of detection (LOD) in Ag NPs concentration was 0.417 × 107 NPs g−1 (the LOD in size was 13.6–16.2 nm). The analytical recovery was 92 and 103% when using Ag NPs standards of 40 and 60 nm, respectively. Several bivalve molluscs (clams, cockles, mussels, razor clams, oysters and variegated scallops) were analysed for total silver content (ICP-MS after microwave assisted acid digestion), and for Ag NPs by the proposed method. Ag NPs concentrations were from 1.56 × 107 to 59.2 × 107 NPs g−1. Mean sizes were within the 26–35 nm range.
•Ag nanoparticles (number of particles and size distribution) in bivalve molluscs•Ultrasound assisted enzymatic hydrolysis as sample pre-treatment for silver nanoparticle isolation•Single particle – inductively coupled plasma – mass spectrometry for silver nanoparticle assessment
A reliable non-destructive testing technique that enables effective detection and quantification of defects within safety-critical curved structures is highly demanded both in manufacture and ...service. Conventional Ultrasonic Testing (UT) methods usually adopt planar ultrasonic probes and it is preferable to adjust the probe axis direction perpendicular to the curved surface, because both the transmitting and receiving sensitivities in the probe axis direction are the highest. This paper proposes a new UT method using a hemispherical-omnidirectional ultrasonic probe. This probe has an omnidirectional directivity pattern and can cover curved surfaces with normal incident ultrasounds at different scan positions without the necessity of adjusting the probe attitude and position to follow the curved surface profiles. A surface reconstruction algorithm is firstly proposed to estimate curved surface profiles, which is based on a fast-imaging algorithm for ultra-wideband radar called the Shape Estimation Algorithm based on the Boundary scattering transform and Extraction of Directly scattered waves (SEABED). This method only uses surface reflection echoes, and thus can inspect curved structures without knowing the surface profiles a prior. Further, the Synthetic Aperture Focusing Technique (SAFT) is implemented to generate a focused image of internal defects by performing delay-and-sum beamforming on defect echoes based on the reconstructed surface profile. The proposed UT method is eventually experimentally verified on a curved plexiglass specimen with 29.4 mm surface curvature radius containing three Ø 3.5 mm Side Drilled Holes (SDHs) at different depths. Results show that compared with the planar ultrasonic probe, the reconstructed surface profile via SEABED is much wider and accurate with a relative error ≤ 0.47%. All SDHs are not only clearly positioned with relative errors ≤ 7.43%, but also can be accurately quantified from the curvature radius of SDH indications in the SAFT images with relative errors ≤ 8.60%. This work proves that the UT method based on the hemispherical-omnidirectional ultrasonic probe can emerge as a promising technique to inspect curved structures with high efficiency and accuracy, which has great potential in practical applications.
•A hemispherical-omnidirectional ultrasonic probe is presented for NDT purposes.•Curved structure is inspected by probe linear scanning with fixed attitude.•Surface profile is reconstructed from surface echo travel times with SEABED.•SAFT is used to generate a focused image with high accuracy.
The energy release from an aluminum dust explosion is related to the degree of turbulence and the local concentration distribution at a given nominal concentration. In the present work, the combined ...effects of turbulence and concentration on aluminum dust/air explosions in a 20 L spherical test vessel were examined using ultrasonic sensors. The relationship between the dust concentration and the ultrasonic attenuation coefficient was established, and real-time online measurements of aluminum dust concentrations were performed. The data show that the turbulent kinetic energy increases sharply during the initial stage of injection and then decreases gradually over time, while the concentration and uniformity of suspended dust gradually increase as the turbulence decreases. Explosion energy data were obtained at various dust concentrations and demonstrate that concentrations from 700 to 900 g/m3 are optimal.
Display omitted
•The ultrasonic signal spectrum had been obtained based on the Hilbert-Huang Transform.•The aluminum dust concentration had been calculated based on the amplitude attenuation of the pulsed ultrasonic frequency.•The results of calculations about turbulence been compared with experimental data.•The concentration distribution and uniformity of aluminum dust diffusion had been analyzed.•Explosion energy data were obtained at different aluminum dust concentrations.
Selecting and designing the optimum ultrasonic probe is vital for ultrasonic measurements and experiments. The amplitude of the emitted ultrasonic wave excitation signal as well as the diameter and ...the natural frequency of the probe seriously affect the validity of the probe results. In this paper, we analyze the significance of the key parameters of the ultrasonic probe theoretically. Further, an external fixed-point liquid level monitoring system was assembled according to the principle of ultrasonic reflection and transmission. On this experimental platform, we study the key parameters of the ultrasonic probe that affect the system evaluation through a simulation and experiment, and select the optimal sensor parameters for this experiment. The evaluations show that under the experimental conditions where the tested container is made of aluminum alloy and its wall thickness is 3 mm, the best results are obtained when the diameter of the ultrasonic sensor is 15 mm, the amplitude of the emitted excitation signal is ±15 V, and the frequency is 1 MHz. The results' average deviation is less than ±0.22 V. The evaluations are consistent with the simulation results. This research can effectively monitor the liquid in the closed, ultra-thin-walled container, and can realize non-contact measurement. It provides an effective basis for the parameters selection and design of the ultrasonic probe in the ultrasonic-based experiments and tests.
PDF
