Surface-enhanced Raman spectroscopy (SERS) with subsequent chemometric evaluation was performed for the rapid and non-destructive differentiation of seven important meat-associated microorganisms, namely Brochothrix thermosphacta DSM 20171^T, Pseudomonas fluorescens DSM 4358, Salmonella enterica subsp. enterica sv. Enteritidis DSM 14221, Listeria monocytogenes DSM 19094, Micrococcus luteus DSM 20030^T, Escherichia coli HB101 and Bacillus thuringiensis sv. israelensis DSM 5724. A simple method for collecting spectra from commercial paper-based SERS substrates without any laborious pre-treatments was used. In order to prepare the spectroscopic data for classification at genera level with a subsequent chemometric evaluation consisting of principal component analysis and discriminant analysis, a data pre-processing method with spike correction and sum normalisation was performed. Because of the spike correction rather than exclusion, and therefore the use of a balanced data set, the multivariate analysis of the data is significantly resilient and meaningful. The analysis showed that the differentiation of meat-associated microorganisms and thereby the detection of important meat-related pathogenic bacteria was successful on genera level and a cross-validation as well as a classification of ungrouped data showed promising results, with 99.5% and 97.5%, respectively.

Hydrophilic surface-enhanced Raman spectroscopy (SERS) substrates were prepared by a combination of TiO₂-coatings of aluminium plates through a direct titanium tetraisopropoxide (TTIP) coating and drop coated by synthesised gold nanoparticles (AuNPs). Differences between the wettability of the untreated substrates, the slowly dried Ti(OH)₄ substrates and calcinated as well as plasma treated TiO₂ substrates were analysed by water contact angle (WCA) measurements. The hydrophilic behaviour of the developed substrates helped to improve the distribution of the AuNPs, which reflects in overall higher lateral SERS enhancement. Surface enhancement of the substrates was tested with target molecule rhodamine 6G (R6G) and a fibre-coupled 638 nm Raman spectrometer. Additionally, the morphology of the substrates was characterised using scanning electron microscopy (SEM) and Raman microscopy. The studies showed a reduced influence of the coffee ring effect on the particle distribution, resulting in a more broadly distributed edge region, which increased the spatial reproducibility of the measured SERS signal in the surface-enhanced Raman mapping measurements on mm scale.

Recent advancements in photoactivated metal oxide (MOX) gas sensors and the application of plasmonic nanoparticles (NPs) in hydrogen sensing have demonstrated significant potential in enhancing sensor performance. Hydrogen, as a high‐energy, carbon‐free alternative to fossil fuels, requires reliable detection methods due to its storage and handling risks. Traditional MOX gas sensors, while cost‐effective and versatile, face challenges such as high operating temperatures and limited selectivity. In this review, innovative photonic methods are explored to overcome these limitations, focusing on photoactivation and plasmonic effects. Photonic activation improves sensitivity, response time, and recovery time at room temperature, mitigating the safety risks associated with high‐temperature operations. Additionally, the integration of plasmonic NPs, made from gold, palladium, or other less noble metals, into MOX gas sensors enhances catalytic activity and sensor response through localized surface plasmon resonance. In this review, also the synergistic effects of noble metal decoration and photonic enhancement are covered, providing a comprehensive overview of the current state and possible future directions in hydrogen‐sensing technology. These advancements promise safer and more efficient hydrogen detection, crucial for the expanding hydrogen infrastructure and its role in a sustainable energy future.

In this work, the surface reactions of the homemade explosive triacetone triperoxide on tungsten oxide (WO₃) sensor surfaces are studied to obtain detailed information about the chemical reactions taking place. Semiconductor gas sensors based on WO₃ nanopowders are therefore produced and characterized by scanning electron microscopy, X‐ray diffraction, and Raman spectroscopy. To analyze the reaction mechanisms at the sensor surface, the sensor is monitored online under operation conditions using Raman spectroscopy, which allows to identify the temperature‐dependent sensor reactions. By combining information from the Raman spectra with data on the changing resistivity of the underlying semiconductor, it is possible to establish a correlation between the adsorbed gas species and the physical properties of the WO₃ layer. In the results, it is indicated that a Lewis acid–base reaction is the most likely mechanism for the increase in resistance observed at temperatures below 150 °C. In the results, at higher temperatures, the assumption of a radical mechanism that causes a decrease in resistance is supported.