Catalyst-Free Oxidation Reactions in a Microwave Plasma Torch-Based Ion/Molecular Reactor: An Approach for Predicting the Atmospheric Oxidation of Pollutants.

The atmospheric oxidation of chemicals has produced many new unpredicted pollutants. A microwave plasma torch-based ion/molecular reactor (MPTIR) interfacing an online mass spectrometer has been developed for creating and monitoring rapid oxidation reactions. Oxygen in the air is activated by the plasma into highly reactive oxygen radicals, thereby achieving oxidation of thioethers, alcohols, and various environmental pollutants on a millisecond scale without the addition of external oxidants or catalysts (6 orders of magnitude faster than bulk). The direct and real-time oxidation products of polycyclic aromatic hydrocarbons and p-phenylenediamines from the MPTIR match those of the long-term multistep environmental oxidative process. Meanwhile, two unreported environmental compounds were identified with an MPTIR and measured in the actual water samples, which demonstrates the considerable significance of the proposed device for both predicting the environmental pollutants (non-target screening) and studying the mechanism of atmospheric oxidative processes.

Wide-energy programmable microwave plasma-ionization for high-coverage mass spectrometry analysis.

Although numerous ambient ionization mass spectroscopy technologies have been developed over the past 20 years to address diverse analytical circumstances, a single-ion source technique that can handle all analyte types is still lacking. Here, a wide-energy programmable microwave plasma-ionization mass spectrometry (WPMPI-MS) system is presented, through which MS analysis can achieve high coverage of substances with various characteristics by digitally regulating the microwave energy. In addition, ionization energy can be rapidly scanned using programmable waveforms, enabling the simultaneous detection of biomolecules, heavy metals, non-polar molecules, etc., in seconds. WPMPI-MS performs well in analyzing real samples, rapidly analyzing nine toxicological standards in one drop of serum, and demonstrating good quantification and liquid chromatography coupling capability. The WPMPI-MS has also been used to detect soil extracts, solid pharmaceuticals, and landfill leachate, further demonstrating its robust analytical capabilities for real samples. The prospective uses of the technology in biological and chemical analysis are extensive, and it is anticipated to emerge as a viable alternative to commercially available ion sources.

Rapid analysis of pharmaceutical and personal care products by soft microwave-based plasma ionization-linear ion trap mass spectrometer (SMPI-LTQ) in natural water.

In this study, a soft microwave plasma torch (SMPT) combined with a mass spectrometer (MS) was used for the first time as an analytical method to detect and analyze various pharmaceutical and personal care products (PPCPs) in aquatic environments without the need for sample pretreatment. For this purpose, ambient SMPT was used to generate plasma for ionizing the analyte molecules. Accordingly, nine PPCPs were identified by the SMPT-MS, and their identification was verified by collision-induced dissociation (CID). The technique's performance was verified with known PPCP samples, and the limits of detection (LOD) and quantification (LOQ) obtained over a linear range of 50-1 µg/L were 1.56 to 2.81 and 2.07 to 3.62 µg/L, respectively, with the standard addition recovery rate falling between 87.14 and 115.16%. These results show that the method has excellent sensitivity and selectivity, suggesting that SMPT can rapidly and directly detect PPCPs in environmental water, making it a promising method for rapid water quality inspection.

Microstructured Gel Polymer Electrolyte and an Interdigital Electrode-Based Iontronic Barometric Pressure Sensor with High Resolution over a Broad Range.

We present a novel iontronic barometric pressure sensor based on a gel polymer electrolyte and interdigital electrodes with a much simpler structure than that of existing devices. By introducing high-density microstructures on the gel polymer electrolyte and one side electrode arrangement configuration, the developed sensor offers high performances with an ultrahigh resolution of 10 Pa, an ultrawide barometric pressure-response range from -92 to 7 kPa, a fast response time of ∼15 ms, and excellent long-term stability. The single pressure sensor is able to detect positive and negative barometric pressures without needing any additional means and can operate as a barometric altimeter with a resolution of about one-floor height. The performances of the sensors significantly surpass those of existing barometric pressure sensors. This work provides a new strategy for making high-performance barometric pressure sensors that are highly sought for commercial applications such as altitude detection, negative pressure ambulance, and consumer electronics.