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Accounting for Molecular Weight Distribution Dynamics in the Environmental Fate Assessment of Water-Soluble Polymers
Full text linkWater-soluble polymers (WSPs) are widely used in industrial and agricultural applications, as well as in consumer products. After use, they may be released into both engineered and natural environments, where their fate is governed by transfer and transformation processes which are strongly influenced by their molecular weight distribution (MWD). Unlike traditional low molecular weight organic chemicals, WSPs are ensembles of molecules with varying chain lengths. This work suggests the use of Monte Carlo (MC) simulations to model shifts in MWDs resulting from abiotic and biotic chain scission reactions in receiving environments. We specify key factors influencing chain-scission selectivity, including chain-end scissions, molecular weight-dependent scissions, and site-specific scissions. Experimental validation of MC simulation predictions presents analytical challenges, requiring high-resolution MWD characterization of WSPs and reliable extraction techniques from complex environmental matrices. MC simulations may play a pivotal role not only in identifying the most relevant molecular weight (MW) ranges for targeted analysis but also in predicting and elucidating environmental chain scission processes
The Swiss Industrial Biocatalysis Consortium (SIBC) turns 20!
Full text linkIn 2024, the Swiss Industrial Biocatalysis Consortium (SIBC), celebrated its 20 years of bringing together experts from the pharma, flavor and fragrance, fine chemicals, and agrochemicals industries to discuss enzyme technology developments. In this perspective, we share recent examples of how our member organizations utilize biocatalysis in their respective industries. While the motivations for employing enzymatic synthesis and the end goals of various production processes may vary, we aim to emphasize the shared aspects that we are coming across. Over the past 20 years, those synergies have provided us with a fruitful basis for pre-competitive knowledge sharing around biocatalysis as a technology. We look forward to many more years of the SIBC and the surprises that await us through the potential of our enzymes
Life Detection Beyond Earth: Laser-Based Mass Spectrometry for Organics Detection on Solar System Objects
Full text linkThe detection and identification of the building blocks of life, from amino acids to more complex molecules such as certain lipids, is a crucial but highly challenging task for current and future space exploration missions in our Solar System. To date, Gas Chromatography Mass Spectrometry has been the main technology applied. Although it has shown excellent performance in laboratory research, it has not yet been able to provide a conclusive answer regarding the presence or absence of a signature of life, extinct or extant, in space exploration. In this contribution we present the current measurement capabilities of our space prototype laser-based mass spectrometer for organics detection. The developed mass spectrometer currently allows the detection and identification of small organic molecules, such as amino acids and nucleobases, at sample concentrations at the level of femtomole mm-2, using the same measurement protocol. The latter is highly relevant to space exploration, since with the instrumentation in use so far only one class of organics can be measured with one instrument configuration
A Scalable Dynamic Cascade Flow Reactor for Challenging Continuous Heterogeneous Processes
Full text linkContinuous processes (often referred to as flow chemistry) offers multiple advantages over batch processes and are of particular interest for industrial applications as they provide a more direct path towards process intensification, increased safety and efficiency. However, some chemical processes are still challenging to run in a continuous fashion, such as reactions producing fouling, using stoichiometric amounts of solids, or requiring long residence times. For those kinds of reactions, batch approaches are usually preferred even though some processes would still benefit from the advantages inherent to flow. We herein report our testing and development of a scalable continuous flow reactor equipped with active mixing that was designed to handle those challenging continuous processes, such as the continuous formation of a Grignard reagent from a magnesium powder slurry
Aerolysin Nanopores for Single-Molecule Analysis
Full text linkBiological nanopores have become powerful tools for single-molecule analysis in many fields, including metal ion detection, single-molecule chemistry, polymer size discrimination, nucleic acid sequencing, and protein/peptide/glycan analysis. Among all biological nanopores, aerolysin is considered one of the most promising nanopores for analytical applications. It is a heptameric β-barrel pore-forming toxin (β-PFT) secreted by Aeromonas, featuring a narrow, elongated β-barrel lumen composed of highly charged amino acids. In this review, we summarize the recent advances of biological nanopores in molecular sensing, sequencing, and their applications in solving biophysical questions, with a focus on aerolysin nanopores
Could Microplasma Ionization and Ultrahigh Mass Resolution Alleviate Chemical Separations for Elemental and Isotopic Analysis?
Full text linkAt the extremes, all analytical spectrometric measurements are limited by the resolution of the spectrometer system. Spectral overlaps, isobars in the case of mass spectrometry, can lead to the implementation of complex and time-consuming chemical separations to alleviate those interferences. In the area of elemental/isotopic mass spectrometry, use of sector-field instruments can provide a mass resolution of ~10,000, but still necessitate chemical separations. Described here is the coupling of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma to ultra-high resolution Orbitrap mass analyzer systems to yield mass resolution values ranging from 70k to 1M. Resolution of this order, with commensurate improvements in precision and accuracy, holds the promise to affect elemental/isotopic determinations without the need for chemical separations
Improving Robustness, Sensitivity and Simplicity of Potentiometric Sensors Through Symmetry and Conceptual Design
Full text link It is an enormous challenge to bring chemical sensing concepts from a controlled laboratory setting into the field while maintaining accuracy. In an environment of uncontrolled, fluctuating temperatures and a lack of repeated calibration, sensor reliability can rapidly deteriorate the accuracy. Today, many sensing concepts are explored for home use or as wearable sensors, and it is paramount to understand and optimize the chemistry for reliable measurements to become possible. This review focuses on the well-established class of potentiometric sensors, mostly known for the measurement of pH, with a range of electrolytes, and how conceptual advances can be used to make them as robust and sensitive as possible. While drawing from recent work of the group at the University of Geneva, the importance of symmetry is stressed to minimize the influence of temperature. The development of self-powered sensing systems that no longer require a battery is explained. This is then connected to protocols in which the sensitivity of these sensors can be reliably improved beyond that dictated by the Nernst equation