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The development of methodologies to detect and quantify azo dyes in treated water is required because some of these dyes exhibit genotoxic activity, even at low concentrations. Here, the construction and characterization of an impedimetric immunosensor for determination of the textile azo dye Disperse Red 1 (DR1) by means of a label-free assay is reported. Anti-DR1 antibodies (Ab anti-DR1) were successfully coupled to glassy carbon electrode (GCE) surface by bonding using electrochemically generated activated carboxylic groups. The concentration of DR1 was measured by the increase in charge transfer resistance (R CT) when the immune reaction occurred, using Fe(CN) 6 3−/4− as a probe. Electrochemical characterizations of the sensor by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed, and infra-red spectra were obtained to complement the electrochemical results showing immobilization of the antibodies. Under optimal conditions, the change in R CT presented a linear relationship with DR1 concentration in the range from 8.40 to 100 nM, and the sensor provided low limit of detection (LOD = 2.52 nM) and quantification (LOQ = 8.40 nM). No significant interference from other azo dyes was observed. The performance of the immunosensor was evaluated using tap water spiked with 20.0 nM DR1 and a satisfactory recovery of 98.5% was found. The proposed immunosensor is simple, relatively inexpensive, and shows good sensitivity for this application.

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REACTIVE NITROGEN GASES AS PRECURSORS OF ATMOSPHERIC AEROSOL: FORMATION REACTIONS, GROWTH PROCESSES AND ENVIRONMENTAL IMPLICATIONS. The increased emissions of reactive nitrogen gases from anthropogenic sources to the atmosphere has been pointed out as responsible for triggering a series of environmental problems at the local, regional, and global scale. Among the many consequences associated with the excess of reactive nitrogen in the environment is the increase of atmospheric aerosol formation. In this way, the present review article aims to provide an overview of the main aerosol formation reactions from the reactive nitrogen gases, their growth processes, and removal from the atmosphere. The paper also addresses the implications of increasing the atmospheric aerosol load, including effects on the planet’s radiative forcing, cloud formation and precipitation, macronutrient dispersion, visibility and human health. The possible relationship between the long-term exposure to these pollutants and COVID-19 fatality is also discussed. The need for more information related to reactive nitrogen gases and atmospheric aerosols is urgent since they act on fundamental processes on planet Earth and their quantity and composition have been abruptly changed over the last hundred years. Therefore, further investigations on this topic should be stimulated and better integrated in order to guide normative decisions and the delineation of possible solutions.