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The facile preparation, characterization, and application of novel dual-shell TpBD (a kind of covalent-organic framework) coated magnetic nanospheres as sorbents for simple, fast, and high selectivity capture of 14 heterocyclic aromatic amines (HAAs) are reported. Quantum chemistry theory calculations were conducted to directly and quantifiably describe the multiple interactions, including π-π, hydrogen bonding, cation-π, static electricity, and ion-exchange, between TpBD and heterocyclic aromatic amines. The excellent adsorption capacity of TpBD coated magnetic nanospheres was further evaluated by extraction of 14 HAAs from nonsmokers' and smokers' urine samples. Under the optimized conditions, the magnetic solid phase extraction process can be completed with high recovery ranging from 95.4% to 129.3%. After being washed with acetonitrile and water successively, the collected sorbents can be easily recycled and reused five times without any significant difference in performance. Coupled with the ultra performance liquid chromatography-tandem mass spectrometer detection, the exposure level of HAAs in nonsmokers and smokers smoking cigarettes with different tar yields were successfully explored. And, this implied that the robust method based on the versatile TpBD coated dual-shell magnetic nanospheres sorbents represents a great potential application in the analysis of disease markers and body fluids.

With respect to massive consumption of ammonia and rigorous industrial synthesis conditions, many studies have been devoted to investigating more environmentally benign catalysts for ammonia synthesis under moderate conditions. However, traditional methods for analysis of synthesized ammonia (e.g., off-line ion chromatography (IC) and chemical titration) suffer from poor sensitivity, low time resolution, and sample manipulations. In this work, charge-transfer ionization (CTI) with O2(+) as the reagent ion based on a vacuum ultraviolet (VUV) lamp in a time-of-flight mass spectrometer (CTI-TOFMS) has been applied for real-time monitoring of the ammonia synthesis in a microreactor. For the necessity of long-term stable monitoring, a self-adjustment algorithm for stabilizing O2(+) ion intensity was developed to automatically compensate the attenuation of the O2(+) ion yield in the ion source as a result of the oxidation of the photoelectric electrode and contamination on the MgF2 window of the VUV lamp. A wide linear calibration curve in the concentration range of 0.2-1000 ppmv with a correlation coefficient (R(2)) of 0.9986 was achieved, and the limit of quantification (LOQ) for NH3 was in ppbv. Microcatalytic synthesis of ammonia with three catalysts prepared by transition-metal/carbon nanotubes was tested, and the rapid changes of NH3 conversion rates with the reaction temperatures were quantitatively measured with a time resolution of 30 s. The high-time-resolution CTI-TOFMS could not only achieve the equilibrium conversion rates of NH3 rapidly but also monitor the activity variations with respect to investigated catalysts during ammonia synthesis reactions.