Coated blade spray (CBS) is a technology based on solid‐phase microextraction (SPME) that has been designed for the quick extraction/cleanup of analytes from complex matrices and direct ...desorption/ionization under ambient mass spectrometry conditions. The entire analytical process can be completed in less than 3 min and enables limits of quantitation in the low picogram‐per‐milliliter region to be reached.
There's no hiding now: Coated blade spray is a technique based on solid‐phase microextraction that has been designed for the quick extraction/cleanup of analytes from complex matrices and direct desorption/ionization under ambient MS conditions. The entire analytical process can be completed within 3 min (see picture; HV=high voltage, SRM=selected reaction monitoring) with limits of quantitation in the low picogram‐per‐millimeter region.
•We describe the evolution and applications of comprehensive chromatography.•Comprehensive 2D chromatography provides powerful methods for the analysis of foods.•We emphasize the coupling of ...comprehensive chromatography and mass spectrometry.
The outstanding selectivity and sensitivity of specific comprehensive two-dimensional chromatography (C2DC) methodologies (particularly with mass-spectrometry detection) have made feasible trace (ppb level), and ultra-trace (ppt level and lower) analysis of target compounds, reducing the need for tedious sample-preparation processes.
The present review can be considered a continuation of a review published in 2004 J. Chromatogr., A 1054 (2004) 3. Rather than an exhaustive description of the C2DC food applications since then, we provide detailed critical descriptions of significant changes and applications.
The aim of this work is to investigate the effect of grain size on slip activity, a critical issue for materials design that remains unsolved. Three pure magnesium polycrystals with average grain ...sizes (d) of 36, 19 and 5 mu m and with very similar textures and grain boundary (GB) misorientation distributions were designed by selecting appropriate rolling and annealing conditions. The three microstructures were tested in tension along the rolling direction (RD) at 50 degree C and at an strain rate of 10-3 s-1 and the incidence of the different deformation mechanisms was evaluated by electron backscattered diffraction (EBSD)-assisted slip trace analysis. A clear transition from non-basal to basal slip-dominated flow takes place when d decreases below 36 mu m, i.e. at grain size ranges that are very relevant for most structural applications. This change in slip activity is shown to be consistent with an increase in the CRSSnon-basal/CRSSbasal ratio with decreasing d, i.e. with a more potent GB strengthening of non-basal than basal systems. Accordingly, a transition in the mechanisms responsible for the accommodation of local stress concentrations at GBs takes place with decreasing grain size. Intergranular compatibility becomes increasingly difficult with grain refinement due to the progressively lower availability of active deformation mechanisms. Macroscopically, these phenomena translate to a reduction of work hardening and ductility with decreasing grain size.
Birds are commonly used as bioindicators, and their feathers are considered suitable tissues for assessing the presence of contaminants, such as trace elements, in the environment. In agroecosystems, ...trace elements’ occurrence can be associated with both natural and anthropogenic processes, including vehicular traffic, traditional fertilizers, food feed additives for livestock, and the use of sewage sludge as fertilizer. Here, we evaluated the concentrations of twelve trace elements (Aluminium, Arsenic, Cadmium, Chromium, Copper, Iron, Mercury, Manganese, Nickel, Lead, Selenium, and Zinc) in the feathers of barn swallow (Hirundo rustica) nestlings. We then compared the concentrations of these elements between nestlings grown in areas amended or not amended with sewage sludge in 2019 and 2020 in a broad region of the Po Plain (Northern Italy). Multivariate analysis showed that the element content of the feathers significantly differed among years and areas, suggesting that the concentration of nestlings’ feathers may indicate the local level of contamination. However, univariate analyses did not show clear spatial differences, possibly due to co-occurring sources of trace elements other than sewage sludge. These results suggest that barn swallow nestlings can be a reliable sentinel for the monitoring of local variation of the environmental occurrence of trace elements.
A sulfation‐controlled binding of heavy metal ions to glycans was realized using electrochemical analysis. The artwork presents glassy carbon electrodes modified by a series of hyaluronans with ...similar sizes but different sulfation patterns. The binding of heavy metal ions to these surfaces resulted in changes of the layer density that produced impedimetric response. The impedimetric response revealed that the selectivity of the hyaluronans to a specific metal ion depends on their sulfation pattern. More information can be found in the Full Paper by J. Rademann, S. Yitzchaik, M. Hurevich, et al. on page 12083.
In this work electron backscattered diffraction-assisted slip trace analysis was utilized to investigate the origin of the high temperature reversed yield asymmetry in a Mg-rare earth alloy. This ...material was tested at room and high temperature, in tension and compression, both in the as-extruded condition, in which the alloying elements are in solid solution, as well as following two aging treatments which gave rise to different precipitation levels. A statistically relevant number of slip traces were analyzed after each test in order to estimate the influence of the testing conditions and the precipitation state on the relative activity of basal, prismatic and pyramidal <c+a> systems. In tension, basal slip was found to be the dominant deformation mechanism under all the testing conditions investigated. In compression, twinning predominated always at room temperature and was replaced by basal slip in the aged samples at high temperature. A pronounced reversed yield asymmetry, i.e., the presence of a higher yield stress in compression than in tension, was observed at high temperature in the aged alloy samples. Careful microstructural examination of the spatial distribution of slip traces by high resolution scanning electron microscopy (SEM) revealed increased intra- and intergranular basal slip localization in those specimens under tensile deformation at high temperature. The high temperature reversed yield asymmetry observed in the aged samples was thus attributed to the suppression of twinning in compression and to enhanced softening in tension due to basal slip localization.
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A monotonic state-trace implies that a single latent factor is sufficient to explain the joint variation between two outcome variables across a set of conditions. There are, however, few methods ...available for assessing how much evidence a sample of data provides about whether the variables are truly monotonically related or not. We present a model that estimates the statistic Mˆ which reflects the amount of evidence a dataset provides about whether two or more outcome variables are jointly monotonically related at the group level. This statistic is based on modeling the covariation between outcome measures in terms of a kernel function, which allows for computation of the latent derivatives of each outcome variable with respect to the other. We then compare the prior and posterior probabilities that these derivatives are all of the same sign (and are thus monotonic) to obtain Mˆ. Simulations show that Mˆ discriminates between monotonic and non-monotonic state traces and an example illustrates how the model can be applied to both continuous and binomial data from between-subjects, within-subjects, or mixed designs.
•Quantifies evidence that two or more outcome variables are jointly monotonic.•Monotonicity implies that these variables can be explained by a single factor.•Bayesian estimation quantifies uncertainty about monotonicity.•Kernel methods allow estimation of plausible relations between outcome variables.
The deformation and fatigue crack nucleation mechanisms were studied by means of slip trace analysis and secondary electron microscopy in a textured AZ31B-O Mg alloy subjected to fully-reversed ...cyclic deformation at two different cyclic strain semi-amplitudes. Samples were deformed in two orientations leading to symmetric and non-symmetric cyclic stress-strain curves due to the activation of different deformation mechanisms. They were ascertained in longitudinal sections of the specimens, which included a large number of grains (from 1500 to 4500 for each specimen), to obtain statistically significant results. If the dominant deformation mechanisms were basal slip and tensile twinning/detwinning, the most damaging fatigue cracks were nucleated along twins in large grains, together with cracks parallel to basal slip bands associated with the localization of deformation in clusters of small grains suitably oriented for basal slip. If the main deformation mechanisms were tensile twinning/detwinning and pyramidal slip, the longest fatigue cracks were nucleated along pyramidal slip bands in large grains. Grain boundary cracks around small grains were found in all cases, but they were not critical from the viewpoint of fatigue failure. This information is relevant to assess the effect of the microstructural features on the fatigue life of Mg alloys and as input to simulate the fatigue behavior of Mg alloys using fatigue indicator parameters.
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The abuse of antibiotics resulted in the pollution of river is more and more serious and it was necessary to exploit a sensitive detection method to improve the traditional analysis measurement. In ...this test, it is reported an Ag-based SERS sensing membrane synthesized by the technique of SERS detection and membrane separation. SERS analysis technique presented sensitive detection property, which could be applied into trace analysis. Membrane separation could effectively enrich the analytes to improve the sensitivity. The SERS membrane was synthesized by filtrating Ag nanoparticles (NPs) on the surface and investigating the amount of PVP and Ag NPs to the sensitivity. Meanwhile, the addition of Ag NPs effectively improved the hydrophilia to promote the detection effectivity in the water. By the investigations of optical analysis, the SERS membrane presented high sensitivity in the detection of antibiotics. Under the optimal condition, the SERS intensity presented good linear relationship with the concentration of antibiotics between 1.0 nmol L−1 and 200 nmol L−1. This method provided a sensitive detection approach and broadened the investigation field of antibiotics detection.
The preparation process had been exhibited in Scheme 1, this study focused on preparing Ag-based SERS analysis system for the detection of enrofloxacin hydrochloride (EH) on the PVDF membrane. Briefly, the PVDF membrane was synthesized by the method of non-solvent induced phase separation (NIPS) and fabricated with amount of Ag NPs by suction filtration to prepare the APM. Moreover, in order to enhance the sensitivity and increase the number of “hot spots”, citric acid was selected to regulate morphology of Ag NPs with flower-like. The APM as a kind of flexible materials could more effectively be applied into detection vessels and avoid the waste caused by the centrifugation. This test provided a novel direction of SERS investigation. Display omitted
•The technique mentioned can avoid the waste caused by the traditional centrifugation.•The surface and amount of Ag nanoparticles were adjusted to improve the sensitivity of the SERS detection.•This method carried out a method which ensured detection sensitivity and observably reduced the detection time.
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