Thursday, November 3, 2022

Chemical Intelligence

'E-nose' sniffs out mixtures of volatile organic compounds
Jun 2022,

Electric nose with porous metal-organic framework films that distinguish xylene isomer mixtures for environmental health monitoring.

Previously, researchers used gas chromatography analysis to identify the three forms of xylene. But this procedure requires large instruments that are expensive, and the analyses are time intensive. 

The researchers prepared six different porous MOF films known to adsorb xylene isomers and applied them to gravimetric sensors in an array called an "e-nose." By analyzing the sensor array data with a machine learning algorithm, the team could determine the composition of the mixtures with 86% accuracy for the 10-ppm mixture and 96% accuracy for the 100-ppm mixture

via Karlsruhe Institute of Technology's Institute of Functional Interfaces and University of Pittsburgh Department of Chemical & Petroleum Engineering: VOC Mixture Sensing with a MOF Film Sensor Array: Detection and Discrimination of Xylene Isomers and Their Ternary Blends, ACS Sensors (2022). DOI: 10.1021/acssensors.2c00301

a detailed blueprint of god, top - secret document 

Nano-sensor detects pesticides on fruit in minutes
Jun 2022,

Current techniques for detecting pesticides on single products before consumption are restricted in practice by the high cost and cumbersome manufacturing of its sensors.

Uses flame-sprayed nanoparticles made from silver to increase the signal of chemicals, "The flame spray can be used to quickly produce uniform surface-enhanced Raman scattering (SERS) films across large areas, removing one of the key barriers to scalability,"

To test the sensors' practical application, the researchers calibrated them to detect low concentrations of parathion-ethyl, a toxic agricultural insecticide that is banned or restricted in most countries. A small amount of parathion-ethyl was placed on part of an apple. The residues were later collected with a cotton swab that was immersed in a solution to dissolve the pesticide molecules. The solution was dropped on the sensor, which confirmed the presence of pesticides.

via Karolinska Institutet: SERS Hotspot Engineering by Aerosol Self-Assembly of Plasmonic Ag Nanoaggregates with Tunable Interparticle Distance, Advanced Science (2022). DOI: 10.1002/advs.202201133

Damaged plants and fake perfumes can be identified rapidly and reliably in real time
Jun 2022,

Chiral detection:

Most natural chiral substances are found in two mirror-image forms present in different relative quantities. Therefore, every plant and every perfume must have its own individual chiral signature.

The relative ratios of the two enantiomers of pinene naturally vary in the emissions of such plants, but critically depend on the state of health of the plant.

Fake perfumes will have a chiral signature that differs from that of the originals.

The Mainz-based researchers have developed a cavity-enhanced polarimetric method for optical chiral analysis to detect the differing optical rotation effects of chiral molecules under polarized light. The researchers have been able to achieve a sensitivity that is better than that of the current state-of-the-art equipment by several orders of magnitude.

via Universitaet Mainz and the Max Planck Institute for Chemistry: Lykourgos Bougas et al, Absolute optical chiral analysis using cavity-enhanced polarimetry, Science Advances (2022). DOI: 10.1126/sciadv.abm3749


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