RESUMEN
Generally, thin-layer chromatography always undertakes the indispensable role in rapid screening and identification of specific compounds. Stationary phase is the core part of thin-layer chromatography with fixed property, which leading to the limitations of separation mode of only regulating the composition of mobile phase. This work was an attempt to fabricate the unique photosensitive thin-layer chromatography to make up the above major drawback. 4-[3-(Triethoxysilyl)propoxy]azobenzene (azo-PTES) was synthesized as photosensitive modifier to fabricate the photosensitive stationary phase, and the transformation of cis-trans structure of azo-PTES proceeds along with polarity difference under 365 nm and 473 nm irradiation. Based on this, the proposed photosensitive thin-layer chromatography shows the reversible switch of polarity of stationary phase by photoinduction, followed by the deserved reversible separation behavior. Furthermore, multi-regulation in spatial dimension was achieved based on the high freedom of spatial regulation of photoinduction, which brings about the integration of stationary phase with different polarity, just by photoinduction. The concept of photosensitive thin-layer chromatography provides new idea for improving separation efficiency and developing multi-dimensional thin-layer chromatography on the one plate.
RESUMEN
To explore the formation mechanism of the ozone ï¼O3ï¼ and emission reduction strategy in a northwestern cityï¼ an extensive field campaign was conducted in summertime in 2021 in Yining Cityï¼ in which the 0-D box model incorporating the latest explicit chemical mechanism ï¼MCMv3.3.1ï¼ was applied for the first time to quantify the O3-NOx-VOCs sensitivity and formulate a precise O3 control strategy in this city. The results showed thatï¼ â the three indicators ï¼»i.e.ï¼ O3 formation potential ï¼OFPï¼ï¼ ·OH reaction rate ï¼k·OHï¼ï¼ and relative incremental reactivity ï¼RIRï¼ï¼½ jointly indicated that alkenesï¼ oxygenated volatile organic compounds ï¼OVOCsï¼ï¼ and aromatics were the highest contributors among anthropogenic volatile organic compounds ï¼AVOCï¼ to O3 formationï¼ and the contribution of biogenic volatile organic compounds ï¼BVOCï¼ also could not be ignored. Additionallyï¼ the results based on RIR calculation implied that that the acetaldehydeï¼ ethyleneï¼ and propylene were the most sensitive individual VOCs species in Yining City. â¡ The in-situ photochemical O3 variations were primarily influenced by the local photochemical production and export process horizontally to downwind areas or vertically to the upper layerï¼ and the reaction pathways of HO2·+ NO and ·OH + NO2 contributed the most to the gross Ox photochemical production ï¼60%ï¼ and photochemical destruction production ï¼53%ï¼ï¼ respectively. Henceï¼ the reduction in local emissions for O3 precursors was more essential to alleviate O3 pollution in this city. ⢠The outcome based on RIRï¼NOxï¼ / RIRï¼AVOCï¼ and EKMA jointly suggested that the photochemical regime in this city can be considered a transitional regime that was also nearly a VOCs-limited regime. Detailed mechanism modeling based on multiple scenarios further suggested that the NOx and VOCs synergic emission reduction strategies was helpful to alleviate O3 pollution. These results are useful to provide policy-related guidance for other cities facing similar O3 pollution in northwest China.