Design of an ultrasonic piezoelectric injection port for analysis of thermally unstable compounds using corona discharge ion mobility spectrometry

High-Performance Piezo-Electrocatalytic Sensing of Ascorbic Acid with Nanostructured Wurtzite Zinc Oxide

Nanostructured piezoelectric semiconductors offer unprecedented opportunities for high-performance sensing in numerous catalytic processes of biomedical, pharmaceutical, and agricultural interests, leveraging piezocatalysis that enhances the catalytic efficiency with the strain-induced piezoelectric field. Here, a cost-efficient, high-performance piezo-electrocatalytic sensor for detecting l-ascorbic acid (AA), a critical chemical for many organisms, metabolic processes, and medical treatments, is designed and demonstrated. Zinc oxide (ZnO) nanorods and nanosheets are prepared to characterize and compare their efficacy for the piezo-electrocatalysis of AA. The electrocatalytic efficacy of AA is significantly boosted by the piezoelectric polarization induced in the nanostructured semiconducting ZnO catalysts. The charge transfer between the strained ZnO nanostructures and AA is elucidated to reveal the mechanism for the related piezo-electrocatalytic process. The low-temperature synthesis of high-quality ZnO nanostructures allows low-cost, scalable production, and integration directly into wearable electrocatalytic sensors whose performance can be boosted by otherwise wasted mechanical energy from the working environment, for example, human-generated mechanical signals.

Benzene-assisted photoionization positive ion mobility spectrometry coupled with a time-resolved introduction for field detecting dimethyl sulfide in seawater

Biogenic dimethyl sulfide (DMS) has attracted widespread attention over several decades due to its potential role in linking ocean biology and climate. The air-to-sea exchange flux, estimated based on marine DMS concentration, offers useful information for evaluating its contribution to climate change. As such, field observation techniques with the characteristics of fast testing speed, portability and easy operation are in demand to accurately monitor the DMS in seawater. In this paper, we proposed a new strategy for the sensitive field measurement of DMS in seawater based on benzene-assisted photoionization positive ion mobility spectrometry (BAPI-PIMS) coupled with a time-resolved introduction. Benzene was employed as a dopant to improve the selectivity by keeping the other sulfur compounds from being ionized, while the two-dimensional data versus drift time and retention time were obtained via an online separating column to eliminate the adverse impact of environmental moisture. Under the optimization conditions, the LODs (S/N = 3) for two product-ion peaks (PIPs) of DMS decreased to 0.081 nmol L^-1. Finally, the established method was applied to the lab and ship-board analysis of seawater from the Bohai Sea and the North Yellow Sea in the summer of 2019, and DMS in surface seawater was in the range of 0.11-23.90 nmol L^-1 with an average of 9.88 ± 6.96 nmol L^-1, indicating the potential for the field detection of marine DMS.