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The microbial contamination of fuels by fungi or bacteria presents risks such as corrosion and fuel system fouling, which can produce critical problems in refineries and distribution systems and has a significant economic impact at every phase of the process. Many factors have been cited as responsible for microbial growth, like the presence of water in the storage tanks. Indeed, only 1 % water in a storage system is enough for the growth of microorganisms like bacteria or yeasts, as well as for the development of fungal biomass at the oil/water interface.1
In this work, a rapid test for the accurate determination of genomic DNA from aqueous fuel extracts is presented. The detection is based on the employment of polystyrene-mesoporous silica core-shell particles, on which modified fluorescent molecular beacons are covalently grafted. Those beacons incorporate in the hairpin loop a target sequence highly conserved in all bacteria, corresponding to a fragment of the 16S ribosomal RNA subunit. The designed single-stranded molecular beacon contained fluorescein as an internal indicator and a quencher in its proximity when not hybridized. Upon hybridization in presence of the target sequence, the indicator and the quencher are spatially separated, resulting in fluorescence enhancement. To perform the assay the designed particles were disposed on different glass fiber strips to try to achieve a portable and sensitive rapid test. Assays showed that presence of genomic DNA extracts from bacteria down to 50–70 μg L-1 induces a fluorescence response. The optical read-out was adapted for on-site monitoring by adapting a 3D-printed case on a conventional smartphone, taking advantages of the CMOS detector sensitivity.2 Such embedded assembly allowed to detect genomic DNA in aqueous extracts down to the mg L-1 range and presents an interesting step toward on-site monitoring of fuel contamination.
The European Commission adopted an EU Energy Label for smartphones and tablets in June 2023. For the first time, the EU Energy Label will depict, among energy efficiency, also a reparability score, battery endurance, battery lifetime, drop resistance and dust and water ingress protection.
However, does the multitude of parameters bear the risk to confuse consumers instead of triggering environmentally sustainable purchase decisions? In a survey in Germany, consumers were asked to make a choice when the label does not clearly identify the environmentally better product. Instead, energy efficiency has to be valued against reparability, reliability against energy efficiency, and reparability against reliability. The sustainability lever of the different aspects is not the same, as e.g. lifetime extension has a much more positive environmental impact than energy efficiency in case of mobile devices. Therefore, the question remains, whether consumers intuitively make the right choice. Results of the survey indicate that consumers interpret the complex label in the desired manner and value those aspects higher, which indeed have a more positive effect on the environment.
The individual willingness to pay for sustainable products is significantly influenced by the climate crisis, but is also affected due to additional international crises as the still ongoing pandemic and the war in Ukraine. The better a product labelling is designed, the more likely consumers are to make a well-considered purchase decision at the point-of-sale, which in turn increases the product lifetime of the devices.
The results of this study are based on two consumer surveys with a total of 590 participants. Consumers were asked to make a simulated purchase decision based on the upcoming EU Energy Label for smartphones. Each consumer was presented comparison labels showing different aspects concerning durability (meaning charging cycles, robustness and IP class), repairability, energy efficiency and product price. In addition, there was a question on energy consumption, which was displayed either in Wh/h or in battery endurance per charge in hours.
The analysis of the survey shows a clear ranking of the preferred properties: 1. Durability as best option, Energy efficiency and Repairability as second and third choice. In all categories, a higher price was accepted in favor of a more environmentally friendly product design. When presenting the energy consumption in Wh/h, no reliable distinguishing between higher or lower values was observed. In contrast, higher values were clearly preferred when choosing between different battery runtimes.
Recommendations will be developed for adjustments to the upcoming EU Energy Label for smartphones and other product labels in the future showing circular economy aspects, such as the durability, repairability, recycled content used during production, recyclability or the total footprint of the product.
The demand for miniaturized analytical devices monitoring important parameters in the food and medical industry has increased strongly in the past decades. With fast progress, smart technologies are finding their way into our everyday life. For the future, it is, therefore, a major goal to also link analytical methods with smart technologies to create user-friendly on-site devices. In food industry the monitoring of harmful substances such as dioxins, heavy metals or mycotoxins plays a key role, since the European Commission prescribes legal limits for various food products and beverages. Therefore, companies often have their own laboratories and trained personnel. For one of the most abundant and toxic mycotoxins, Ochratoxin A (OTA) we want to present an electrochemical detection system in which the read-out can be performed with a smartphone connected via Bluetooth to a miniaturized potentiostat. The recognition of OTA is performed with specific antibodies in a competitive assay format. Anti-OTA-antibodies were captured on magnetic beads on which the competitive binding between OTA and an OTA horseradish peroxidase (HRP) tracer was performed. To quantify OTA, the enzymatic reaction of the tracer with 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 is employed. Oxidized TMB, which is enzymatically produced by the reduction of H2O2, is quantified by amperometry with screen-printed electrodes in a custom-made flow system. Since it is well-known that oxidized TMB can precipitate on electrode surfaces, we have studied pitfalls of the electrochemical detection of TMB. By cyclic voltammetry we have compared the stability of the electrochemistry of TMB at different electrode materials (gold and carbon) and pH values (pH 1 and pH 4). It was found that a stable response of the electrode could be achieved at pH 1 on gold electrodes. Thus, we applied these reaction conditions for amperometric detection of TMB in the OTA assay. The results of the electrochemical detection method are in good correlation with the photometric detection of TMB. To demonstrate the applicability, we tested our system with OTA-spiked beer and performed the measurement via smartphone.
The demand for miniaturized analytical devices monitoring important parameters in the food and medical industry has increased strongly in the past decades. With fast progress, smart technologies are finding their way into our everyday life. For the future, it is, therefore, a major goal to also link analytical methods with smart technologies to create user-friendly on-site devices. In food industry the monitoring of harmful substances such as dioxins, heavy metals or mycotoxins plays a key role, since the European Commission prescribes legal limits for various food products and beverages[1]. Therefore, companies often have their own laboratories and trained personnel. For one of the most abundant and toxic mycotoxins, Ochratoxin A (OTA) we want to present an electrochemical detection system in which the read-out can be performed with a smartphone connected via Bluetooth to a miniaturized potentiostat. The recognition of OTA is performed with specific antibodies in a competitive assay format. Anti-OTA-antibodies were captured on magnetic beads on which the competitive binding between OTA and an OTA horseradish peroxidase (HRP) tracer was performed. To quantify OTA, the enzymatic reaction of the tracer with 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 is employed. Oxidized TMB, which is enzymatically produced by the reduction of H2O2, is quantified by amperometry with screen-printed electrodes in a custom-made flow system. Since it is well-known that oxidized TMB can precipitate on electrode surfaces[2], we have studied pitfalls of the electrochemical detection of TMB. By cyclic voltammetry we have compared the stability of the electrochemistry of TMB at different electrode materials (gold and carbon) and pH values (pH 1 and pH 4). It was found that a stable response of the electrode could be achieved at pH 1 on gold electrodes. Thus, we applied these reaction conditions for amperometric detection of TMB in the OTA assay. The results of the electrochemical detection method are in good correlation with the photometric detection of TMB. To demonstrate the applicability, we tested our system with OTA-spiked beer and performed the measurement via smartphone.
Contamination of natural bodies of water or soil with oils and lubricants (or generally, hydrocarbon derivatives such as petrol, fuels, and others) is a commonly found phenomenon around the world due to the extensive production, transfer, and use of fossil fuels. In this work, we develop a simple system for the on-field detection of total petroleum hydrocarbons (TPHs) in water and soil. The test is based on the measurement of the fluorescence signal emitted by the molecular rotor 2-[ethyl[4-[2-(4-nitrophenyl)ethenyl]phenyl]amino]ethanol (4-DNS-OH). This dye is embedded in a hydrophobic polymeric matrix (polyvinylidene fluoride), avoiding interactions with water and providing a robust support for use in a test strip fashion. Together with the strips, an embedded optical system was designed for fluorescence signal read-out, featuring a Bluetooth low-energy connection to a commercial tablet device for data processing and analysis. This system works for the detection and quantification of TPHs in water and soil through a simple extraction protocol using a cycloalkane solvent with a limit of detection of 6 ppm. Assays in surface and sea waters were conclusive, proving the feasibility of the method for in-the-field operation.
Ein neu entwickeltes thermoplastisches Polyurethan (TPU) ist alles andere als „vergesslich". Formteile aus dem Material lassen sich in einer temporären Form fixieren und wieder nahezu in ihre ursprüngliche Gestalt zurückverwandeln. Dieser Formgedächtniseffekt hat gute Anwendungschancen - vom Marken- und Produktschutz über den Maschinen- und Automobilbau, bis hin zur Freizeit- und Spielzeugindustrie.
Auch Kunststoffe können sich erinnern. Das zeigt das Beispiel eines neuen thermoplastischen Polyurethans. Das Formgedächtnispolymer kann vorübergehend in einem deformierten Zustand fixiert und dann wieder nahezu in seine ursprüngliche Gestalt zurückverwandelt werden. Einsatzchancen hat es unter anderem im Markenschutz und Maschinenbau sowie in der Textil-, Sport-, Freizeit- und Spielzeugindustrie.
Mit Formgedächtnispolymeren auf Basis von TPU sind Bauteile spritzgieß- oder extrudierbar, die sich vorübergehend durch eine gezielte thermomechanische Behandlung in einer anderen temporären Form fixieren und stabilisieren lassen. Damit können Informationen gespeichert, vorübergehend sicher verschlüsselt und als Quick Response (QR)-Codes mit schaltbarer Lesbarkeit auf TPU-Etiketten eingraviert werden.
The fluorescence properties of three molecular rotors, related to 4-dimethylamino-4-nitrostilbene (4-DNS), are studied versus different diesel/kerosene blends. In nonviscous solvents, these compounds can populate a twisted intramolecular charge transfer state which deactivates nonradiatively, successfully suppressing fluorescence emission. Solution experiments with diesel/kerosene blends showed a good linear correlation between the fluorescence intensity of the probe molecules and the diesel fraction of the blend. The dyes have been immobilized on paper, retaining their fluorescence behavior, i.e., negligible emission in the presence of nonviscous organic solvents and increasing fluorescence when the environment is increasingly viscous. When the impregnated paper is devised as a test strip, the latter is compatible with a newly designed smartphone reader system, which allows in-the-field measurements. The method can safely detect the presence of kerosene in diesel at ≥7%, which competes favorably with current standard methods for the detection of diesel adulteration.