A Flexible Chemosensor Based on Colorimetric and Fluorescent Dual Modes for Rapid and Sensitive Detection of Hypochlorite Anion

A flexible chemosensor has been developed based on colorimetric and fluorescent dual modes using tetraphenylethylene-centered tetraaniline (TPE4A) for rapid and sensitive detection of hypochlorite anion. The fluorescent probe TPE4A exhibits a unique aggregation-induced emission (AIE) character which is proved by a blue shift of the fluorescent peak from 544 to 474 nm with the water equivalents increasing. With the addition of hypochlorite in solution, the absorbance of the probe changes and the responding fluorescence color can be observed to change from light green to purple. The detection limit of hypochlorite is 1.80 × 10−4 M in solution, and the visual detection limit is 1.27 µg/cm2 with the naked eye for the flexible paper-based chemosensor. The proposed flexible chemosensors show a good selectivity and sensitivity which has great potential for effective detection of hypochlorite anions without any spectroscopic instrumentation.

Uncovering the illegible: multi-analytical approach to reveal paint stratigraphy of corroded signposts from the Auschwitz-Birkenau State Museum

Object discoveries from the Auschwitz-Birkenau State Museum (PMA-B) in Poland challenge the efforts to preserve paint on corroded steel supports. The objects have been exposed to outdoor weathering conditions and then buried for about 65 years. This caused severe damage, such as corrosion and paint delamination. The fragile condition of such cultural heritage objects makes their preservation difficult and comprehensive studies for paint conservation are lacking. Additionally, a thorough investigation of used materials is needed to put objects produced by forced labour in historical context. In this study, we analysed signposts from the Auschwitz-Birkenau State Museum (Poland) collection to gain information about used materials, the object’s genesis as well as damage phenomenology. Literature research suggests that the signposts may be produced within the former German NAZI concentration and extermination camp. Inorganic constituents were identified using elemental analysis, such as X-ray fluorescence (XRF) and scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM–EDS). Organic matter was analysed utilizing vibrational spectroscopic instrumentation Fourier transform infrared spectroscopy (FTIR). Our results include the use of synthetic organic pigments (SOPs) and binders, which were newly emerged paint materials at that time. The study highlights the need for conservators to have detailed understanding of composite materials and demonstrates the need for further investigation concerning painted steel objects.

Whole-Organism Analysis by Vibrational Spectroscopy

Vibrational spectroscopy has contributed to the understanding of biological materials for many years. As the technology has advanced, the technique has been brought to bear on the analysis of whole organisms. Here, we discuss advanced and recently developed infrared and Raman spectroscopic instrumentation to whole-organism analysis. We highlight many of the recent contributions made in this relatively new area of spectroscopy, particularly addressing organisms associated with disease with emphasis on diagnosis and treatment. The application of vibrational spectroscopic techniques to entire organisms is still in its infancy, but new developments in imaging and chemometric processing will likely expand in the field in the near future.

Astrophotonic Spectrographs

Astrophotonics is the application of photonic technologies to channel, manipulate, and disperse light from one or more telescopes to achieve scientific objectives in astronomy in an efficient and cost-effective way. Utilizing photonic advantage for astronomical spectroscopy is a promising approach to miniaturizing the next generation of spectrometers for large telescopes. It can be primarily attained by leveraging the two-dimensional nature of photonic structures on a chip or a set of fibers, thus reducing the size of spectroscopic instrumentation to a few centimeters and the weight to a few hundred grams. A wide variety of astrophotonic spectrometers is currently being developed, including arrayed waveguide gratings (AWGs), photonic echelle gratings (PEGs), and Fourier-transform spectrometer (FTS). These astrophotonic devices are flexible, cheaper to mass produce, easier to control, and much less susceptible to vibrations and flexure than conventional astronomical spectrographs. The applications of these spectrographs range from astronomy to biomedical analysis. This paper provides a brief review of this new class of astronomical spectrographs.