Abstract: A new method to estimate case specific prediction uncertainty for univariate trilinear partial least squares (tri-PLS1) regression is introduced. This method is, from a theoretical point of view, the most exact finite sample approximation to true prediction uncertainty that has been reported up till now. Using the new method, different error sources can be propagated, which is an advantage that cannot be offered by data driven approaches such as the bootstrap. In a concise example, it is illustrated how the method can be applied. In the Appendix, efficient algorithms are presented to compute the estimates required.

Abstract: Airborne particulate matter (PM) includes semi-volatile organic compounds (SVOCs), which can be deposited on vegetation matrices such as plant leaves. In alternative to air-point measurements or artificial passive substrates, leaf monitoring offers a cost-effective, time-integrating means of assessing local air quality. In this study, leaf washing solutions from ivy (Hedera hibernica) leaves exposed during one-month at different land use classes were explored via comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS). The composition of leaf-deposited SVOCs, corrected for those of unexposed leaves, was compared against routinely monitored pollutants concentrations (PM10, PM2.5, O3, NO2, SO2) measured at co-located air monitoring stations. The first study on leaf-deposited SVOCs retrieved from washing solutions, herein reported, delivered a total of 911 detected compounds. While no significant land use (rural, urban, industrial, traffic, mixed) effects were observed, increasing exposure time (from one to 28 days) resulted in a higher number and diversity of SVOCs, suggesting cumulative time-integration to be more relevant than local source variations between sites. After one day, leaf-deposited SVOCs were mainly due to alcohols, N-containing compounds, carboxylic acids, esters and lactones, while ketones, diketones and hydrocarbons compounds gained relevance after one week, and phenol compounds after one month. As leaf-deposited SVOCs became overall more oxidized throughout exposure time, SVOCs transformation or degradation at the leaf surface is suggested to be an important phenomenon. This study confirmed the applicability of GCxGC-TOFMS to analyze SVOCs from leaf washing solutions, further research should include validation of the methodology and comparison with atmospheric organic pollutants.

Abstract: We introduce a rapid method to test the photocatalytic activity of singlet‐oxygen‐producing photosensitizers using a batch cell, a LED laser and a conventional potentiostat. The strategy is based on coupling of photo‐oxidation of hydroquinone and simultaneous electrochemical reduction of its oxidized form at a carbon electrode in an organic solvent (methanol). This scheme gives an immediate response and avoids complications related to long‐term experiments such as oxidative photo‐degradation of photosensitizers and singlet oxygen traps by reactive oxygen species (ROS). Among the tested compounds, a fluoro‐substituted subphthalocyanine showed the highest photocurrent and singlet oxygen quantum yield (ΦΔ) in comparison to phenoxy‐ and tert‐butyl‐substituted analogues, whereas the lowest photocurrents and yields were observed for aggregated and dimeric phthalocyanine complexes. The method is useful for fast screening of the photosensitizing activity and represents the first example of one‐pot coupling of electrochemical and photocatalytic reactions in organic media.

Abstract: Suspended particles and dissolved substances in water provide reactive surfaces, influence metabolic activity and contribute to the net sediment deposition. It therefore plays an important part in the ecology and quality of the water mass. The water quality in reservoirs is crucial and it is naturally maintained by flushing and sedimentation, which continuously remove phosphorus from the water. In some reservoirs, however, these removal processes are countered by recycling of ions which could play a key role to start and/or maintain the eutrophic state. The combination of macro-, trace- and microanalysis techniques can be useful to trace pollution sources through a chemical fingerprint, whether be during an acute environmental disaster or a long-term release of pollutants. The water quality and total metal content of reservoir sediments were assessed in a reservoir, situated in the capital of the Paraná State, in the South-Eastern part of Brazil. The goal of this paper was to determine the metal presence in the sediment and metal and ionic speciation in the Green River reservoir water. Water and bed sediment samples, collected from various sites during 2008 and 2009, were investigated using XRF, ICP-OES, ICP-MS, XRD and zeta potential measurements. Based on the results, the heavy metal concentration and chemical composition of the suspended matter in the water samples, as well as the sediment's chemical composition will be discussed.

Abstract: Using laser microprobe mass analysis, we studied the ultrastructural localization of aluminum in liver and bone tissue of chronic-hemodialysis patients with proven aluminum-induced osteomalacia. In the liver, aluminum was observed to be almost exclusively associated with iron. Detectable aluminum and large amounts of iron were found in lysosomes of both hepatocytes and Kupffer cells. In bone, aluminum was localized at the osteoid/calcified-bone interface and also was associated with iron in some cases.

Abstract: Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-mu-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-mu-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5-15 mu m on the less porous stone, while a 20-30 mu m thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer.

Abstract: Assay and electrochemical behaviour of betahistine hydrochloride in BrittonRobinsons (BR) buffer of pH range 2.512.0 at a glassy carbon electrode have been investigated. Addition of anionic surfactant (sodium lauryl sulphate) to the betahistine hydrochloride solution containing electrolyte enhanced the reduction current signal while neutral surfactant (Tween-20) and cationic surfactant cetyl trimethylammonium bromide (CTAB) showed an opposite effect. Voltammograms of betahistine hydrochloride exhibited a single wave. Based on reduction behaviour of betahistine hydrochloride, a direct square-wave voltammetric method has been developed for the assay of betahistine hydrochloride in pharmaceutical formulation. The proposed method has been validated as per ICH guideline. System and method precision in terms of RSD were 1.88% and 1.60% respectively, whereas the method accuracy was indicated by the recovery of 97.6101.9%. Reduction peak current was linear over the target concentration with correlation coefficient 0.998. The proposed method was successfully applied to the determination of betahistine hydrochloride in pharmaceutical formulation. The results were compared with those obtained by the reference high performance liquid chromatographic method. No significant differences were found between results of proposed and reference methods.

Abstract: A sensitive electroanalytical method for determination of gemifloxacin in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at multi-walled carbon nanotubes modified glassy carbon electrode in the presence of CTAB. Solubilized system of different surfactants including SDS, Tween-20 and CTAB were taken for the study of electrochemical behaviour of gemifloxacin at modified electrode. The reduction peak current increases in the presence of CTAB while other surfactants show opposite effect. The modified electrode exhibits catalytic activity, high sensitivity, stability and is applicable over wide range of concentration for the determination of gemifloxacin. The mechanism of electrochemical reduction of gemifloxacin has been proposed on the basis of CV, SWV, DPV and coulometeric techniques. The proposed squarewave voltammetric method shows linearity over the concentration range 2.4715.5 μg/mL. The achieved limits of detection (LOD) and quantification (LOQ) are 0.90 ng/mL and 3.0 ng/mL respectively.

Abstract: Synchrotron-based techniques are increasingly used in the field of cultural heritage, and this review focuses notably on the application of nano-beams to access high-spatial-resolution information on fragments sampled in historical or model artworks. Depending on the targeted information, various nano-analytical techniques can be applied, providing both identification and localization of the various components. More precisely, nano-X-ray fluorescence probes elements, nano-X-ray diffraction identify crystalline phases, and nano X-ray absorption spectroscopy is sensitive to speciation. Furthermore, computed tomography-based techniques can provide useful information about the morphology and in particular the porosity of materials. (C) 2018 Academie des sciences. Published by Elsevier Masson SAS.

Abstract: The main goal of this work was to determine the chemical composition of building materials used in Turkey by utilizing energy dispersive X-ray fluorescence (EDXRF) spectrometry. Gas concrete, cement, sand, bricks, roofing tiles, marble, lime and gypsum materials were selected as building materials for this research. The chemical contents and their trace concentrations of the selected samples were determined. The most abundant oxides measured were generally SiO2, Al2O3, CaO, MgO, Fe2O3, K2O and SO3 for all samples. While the main chemical component of gas concrete, cement, sand and marble samples were SiO2 and CaO, brick and roofing tile mainly consisted of SiO2 and Al2O3. CaO and SO3 were major component of lime and gypsum samples, respectively. For U and Th concentrations in the samples, activities of 226Ra and 232Th were measured by utilizing gamma spectrometry. ANOVA and Pearson correlation analyses were performed on the studied data for statistical analysis.

Abstract: Allergic contact dermatitis caused by polyvinyl chloride gloves is rarely reported, and in only 2 cases was bisphenol A considered to be the responsible sensitizer. We report a patient with occupational hand dermatitis after the use of a new type of high-density vinyl (HDV) gloves. Patch tests showed positive (++) reactions to both used and new HDV gloves and to bisphenol A. Chemical analysis by gas chromatography-mass spectrometry demonstrated the presence of bisphenol A in the HDV gloves. Replacement by nitrile rubber gloves resulted in complete clearance of the hand dermatitis.

Abstract: Galvanised iron is popular in many applications, particular as a roofing material. However, just like other materials, especially metallic ones, it is prone to degradation by corrosion. In this particular study, the degradation of galvanised roof sheets was investigated at a coastal, urban and rural site in Tanzania, Africa. Samples were exposed to various outdoor environments over a period of 3 years. In addition, some accelerated laboratory investigations were conducted in different simulated air pollution environments in an artificial corrosion chamber constructed for this purpose to supplement the outdoor exposure tests. It was found that the combination of the tropical climate and increasing air pollution due to industrial development in the capital Dar-es-Salaam resulted in substantial atmospheric corrosion of the roof sheets, which eventually leads to failure and the necessity for replacement. The rural site had the lowest degree of atmospheric corrosion as expected. A combination of different corrosion products was identified as a result of the atmospheric corrosion by Raman and EDX analyses. The information gained from this investigation could be utilised to construct more durable structures requiring less frequent replacement and maintenance in future.

Abstract: The presence of residues from frequent antibiotic use in animal feed can cause serious health risks by contaminating products for human consumption such as meat and milk. The present article gives an overview of the electrochemical methods developed for the detection of phenicol antibiotic residues (chloramphenicol, thiamphenicol, and florfenicol) in different kinds of foodstuffs. Electrochemical sensors based on different biomolecules and nanomaterials are described. The detection limit of various developed methods with their advantages and disadvantage will be highlighted.