Real-time sensing of Chemical Warfare Agents (CWAs) is today a crucial topic to prevent lethal effects of a chemical terroristic attack. For this reason, the development of efficient, selective, sensitive and reversible sensoristic devices, able to detect by optical response ppm levels of these compounds, both in water and in air, is strongly required. Here we report the design and synthesis of a fluorescent nanosensor, based on carbon nanoparticles covalently functionalized with ethanolamine arms, which exploits the multitopic supramolecular interaction with nerve agents, ensuring highly efficient (logK 6.46) and selective molecular recognition. Moreover, given the aqueous dispersibility of carbon nanoparticles, these nanosensors ensure even higher sensitivity, detecting sub-ppt concentration of nerve agents in water, and sub-ppm level in air by using a common digital camera or a smartphone. Our results pave the way to an innovative class of low-cost reusable CWA sensors prompting, for the first time, the simultaneous detection of nerve agents through gaseous and aqueous media, thus extending the protection range to public water supplies.

Fluorescent carbon quantum dots (CDs) are synthesized and employed as fluorescent nanochemosensors for selective detection of amino acids. A detailed investigation of excitation–emission maps revealed that the fluorescence properties of CDs are intensely and strongly influenced by the interaction at the surface with different amino acids. The discrimination capability was demonstrated by tensor rank decomposition of the differences induced by the surface reaction in the excitation–emission maps and by means of a common machine learning approach based on artificial neural networks.

Direct solid analysis of bulk and thin coated glasses by pulsed radiofrequency (rf) glow discharge time-of-flight mass spectrometry (GD-TOFMS) is investigated. Modulated low pressure plasma created by pulsed-rf-GD has been coupled to a fast TOFMS in order to obtain complete mass spectra information from the different GD pulse domains (pre-peak, plateau and afterglow). In particular, it was observed that the analytes show the highest atomic ion signals in the afterglow region some hundred microseconds after the maximum of the Ar ion signal. However, it should be highlighted that the analyte ions exhibited their peak maxima at different delay times, depending on the element, after the end of the GD pulse. Such ion signal delays have been measured for different selected isotopes, covering a mass spectrum from light to heavy isotopes at different conditions of pressure and applied power. The results showed that ion signal delays are influenced by both the isotope mass and the pressure of the GD. Furthermore, GD operating conditions (pressure and applied power) were optimised in terms of sensitivity, using a bulk glass certified reference material (NIST 1411). The best analytical performance was observed at low pressure (150–200 Pa) and high applied power (135 W). Moreover, different pulse GD duty cycles (relationship between pulse duration and pulse period) were investigated. An optimum value of 50–65% duty-cycle was selected considering the signal stability and the signal intensity. The previously optimized pulsed-rf-GD-TOFMS system was then evaluated for qualitative in-depth profile analysis of thin coatings deposited onto thick glass substrates. High depth resolution (nm range), comparable to that obtained using rf-GD-OES was achieved. However, the observed depth resolution using the ToF-SIMS system is still superior. In this sense, analytical figures of merit observed in our pulsed-rf-GD-TOFMS demonstrate its great analytical potential for high depth resolution analysis of coated glasses.