"Iridium Signature" Mass Spectrometric Probes: New Tools Integrated in a Liquid Chromatography-Mass Spectrometry Workflow for Routine Profiling of Nitric Oxide and Metabolic Fingerprints in Cells.

Nitric oxide (NO) is a highly reactive signaling molecule involved in diverse biological processes. Simultaneous profiling of NO and associated metabolic fingerprints in a single assay allows more accurate assessments of cell states and offers the possibility to better understand its exact biological roles. Herein, a multiplexing LC-MS workflow was established for simultaneous detection of intracellular NO and various metabolites based on a novel "iridium signature" mass spectrometric probe (Ir-MSP841). This Ir-MSP841 can convert highly liable NO to a stable permanently charged triazole product (Ir-TP852), enabling direct MS detection of NO. This 191/193Ir-signature mass spectrometric probe-based approach is endowed with overwhelming advantages of interference-free, high quantitative accuracy, and great sensitivity (limit of detection down to 0.14 nM). It also reveals good linearity over a wide concentration range 12.5-500 nM and has been successfully employed for exploring the release behaviors of three representative NO donors in cells. Meanwhile, metabolic profiling results reveal that varying the concentrations of NO has distinct effects on various cellular metabolites. This study provides a robust, sensitive, and versatile method for simultaneous detection of NO and numerous metabolites in a single LC-MS run and expands its applications in biomedical research.

Chemiluminescence-assisted study on a peracetic acid-based advanced oxidation process activated with cobalt phosphide.

In recent years, the elimination of organic pollutants using advanced oxidation processes (AOPs) based on peracetic acid (PAA) has drawn increasing attention due to the high oxidative potential and low byproducts. However, to explore more efficient and stable PAA-based AOPs, there is still great room for study on the activation of PAA and degradation mechanism in the reaction process. In this study, a new PAA-based AOP activated by metal-organic framework-derived cobalt phosphide (CoP) and accompanied by chemiluminescence (CL) behaviour was explored. The CoP/PAA system could efficiently degrade 99.98% of RhB (20 mg L-1 ) within 5 min at pH 7 compared with the conventional Co3 O4 /PAA system (merely 17.29%), and the degradation process was matched well with the pseudo-first-order kinetic, and the kinetic constants was ~23.7 times higher than that of Co3 O4 (0.546 min-1 for CoP vs. 0.023 min-1 for Co3 O4 ). In the CoP/PAA/RhB process, the CL intensity was related to the concentration of 1 O2 , O2 •- and acetyl peroxyl radicals [CH3 C(O)OO• and CH3 C(O)O•]. Therefore, CL analysis, combined with quenching tests and electron paramagnetic resonance analysis, was used to study the degradation mechanism in detail, and 1 O2 was confirmed as the dominant contributor for the dye degradation.

Cataluminescence System Coupled with Vacuum Desorption-Sampling Methodology for Real-Time Ozone Sensing during the Self-Decomposition Process on Functional Boron Nitride.

The treatment and detection of ozone have been widely studied in recent decades with respect to toxicity and contamination, while the measurement method of ozone is relatively toneless. Fortunately, a new concept of the cataluminescence (CTL) sensor provides a scheme of real-time ozone sensing in a tiny system. Here, a novel CTL sensor system was specially developed with silica-hydroxyl functional boron nitride as the sensing material for rapid and sensitive ozone detection. Coupled with the construction of a pulse vacuum static sampling system, ozone on the surface of sensing material can be desorbed rapidly and can step into the next detection circulation in a few seconds. Based on the strong emission initiated by the transient of reactive oxygen species (ROS) including singlet oxygen, a trioxide group, and an oxygen radical, the detection limit of ozone could be optimized to be as low as 51.2 ppb. Besides, the sensor system exhibited remarkable anti-interference performance in which humidity changes and common VOCs do not disturb or weakly disturb ozone sensing, and the CTL mechanism of the multistep degradation process was further discussed on the basis of multiple pieces of experimental evidence and a DFT transient calculation. A real-time degradation-sensing module was further attached to the system to realize the functions of ozone decomposition and real-time monitoring.

Cataluminescence Coupled with Photoassisted Technology: A Highly Efficient Metal-Free Gas Sensor for Carbon Monoxide.

With the development of green chemistry, metal-free nanocatalysts have gradually substituted metal-based materials, causing widespread concern among researchers in many fields, especially in cataluminescence sensing, because of their long-term stability and environmental friendliness as well as low costs. Besides the catalysts, innovations of assistant technologies for cataluminescence are needed to enhance the oxidation reactivity of the gas molecules or catalytic efficiency of sensing materials. Although, there are some groups enhancing the cataluminescence reaction via various assistant technologies, the development of assistant technologies in cataluminescence sensors is still in its infancy; the design, effect mechanism, and application are still stimulating challenges. Herein, with photodynamic assistant, fluorinated nanoscale hexagonal boron nitride is first employed as a metal-free catalyst to establish a novel cataluminescence method for detecting CO gases, and the cataluminescence reaction mechanism of CO is also investigated in detail. Under the best conditions, the detection limit (3σ) of the CO concentration is 0.005 µg mL-1, which has been largely improved in cataluminescence methods. The realization of detection of CO from theory to practice through the method of cataluminescence is beneficial for the practical application of metal-free catalysts to detect CO rather than staying at the possibility to detect CO by means of theoretical calculation only.

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres.

The detection and monitoring of dichloroalkanes, which are typical chlorinated volatile organic compounds (CVOCs) with obvious biological toxicity, is of significance for environmental pollution and public health. Herein, a novel ozone-activated cataluminescence (CTL) sensor system based on silica nanospheres was developed for highly sensitive and fast quantification of dichloroalkanes. A typical CTL system coupled with a plasma-ozone-assist unit was designed for promoting the CTL response of dichloroalkanes. The ozone generated by plasma provides a new pathway of catalytic oxidation process, which accompanied by the CTL signal amplification of dichloroalkanes results in an enhanced CTL sensor system with improved limit of detection (1,2-dichloroethane: 0.04 µg mL-1, 1,2-dichloropropane: 0.03 µg mL-1) and benign selective performance under the interference of CO2, H2O, NO, NO2, SO2, CS2, and other common CVOCs. Moreover, a segmented CTL mechanism including co-adsorption of ozone and dichloroalkanes, thermal elimination, the ozonation route, and a luminous step was ratiocinated based on multiple characterizations and discussion. The proposed methodology and theory open up an attractive perspective for the analysis of less active volatile organic compounds.