People spend up to 90% of their time indoors, and yet our understanding of indoor air quality and the chemical processes driving it are poorly understood, despite levels of key pollutants typically being higher indoors compared to outdoors. Nitrous acid (HONO) is a species that drives these indoor chemical processes, with potentially detrimental health effects. In this work, a BODIPY-based probe was synthesized with the aim of developing the first selective passive sampler for atmospheric HONO. Our probe and its products are easily detected by UV-Vis spectroscopy with molar extinct coefficients of 37 863 and 33 787 M⁻¹ cm⁻¹, respectively, and a detection limit of 14.8 ng mL⁻¹. When protonated, the probe fluoresces with a quantum yield of 33%, which is turned off upon reaction. The synthesized BODIPY probe was characterized using NMR and UV-Vis spectroscopy. Products were characterized by UV-Vis and ultra high-resolution mass spectrometry. The reaction kinetics of the probe with nitrite was studied using UV-Vis spectroscopy, which had a pseudo-first-order rate of k = 7.7 × 10⁻⁴ s⁻¹. The rapid reaction makes this probe suitable for targeted ambient sampling of HONO. This was investigated through a proof-of-concept experiment with gaseous HONO produced by a custom high-purity calibration source delivering the sample to the BODIPY probe in an acidic aqueous solution in clean air and a real indoor air matrix. The probe showed quantitative uptake of HONO in both cases to form the same products observed from reaction with nitrite, with no indication of interferences from ambient NO or NO₂. The chemical and physical characteristics of the probe therefore make it ideal for use in passive samplers for selective sampling of HONO from the atmosphere.

中文翻译：

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一种基于硼二吡咯甲烯 (BODIPY) 的探针，用于室内大气亚硝酸 (HONO) 的选择性被动采样

人们多达 90% 的时间都在室内度过，但我们对室内空气质量及其驱动化学过程的了解却知之甚少，尽管与室外相比，室内的主要污染物水平通常更高。亚硝酸 (HONO) 是驱动这些室内化学过程的一种物质，具有潜在的有害健康影响。在这项工作中，合成了一个基于 BODIPY 的探针，目的是开发第一个用于大气 HONO 的选择性被动采样器。我们的探针及其产物可通过紫外-可见光谱轻松检测，摩尔消光系数分别为 37 863 和 33 787 M ^-1 cm ^-1，检测限为 14.8 ng mL ^-1. 当质子化时，探针以 33% 的量子产率发出荧光，在反应时关闭。合成的 BODIPY 探针使用 NMR 和 UV-Vis 光谱进行表征。产品通过紫外-可见光和超高分辨率质谱进行表征。使用紫外-可见光谱研究了探针与亚硝酸盐的反应动力学，其准一级速率为k = 7.7 × 10 ^-4 s ^-1. 快速反应使该探针适用于 HONO 的目标环境采样。这是通过概念验证实验来研究的，该实验使用定制的高纯度校准源产生的气态 HONO，将样品在清洁空气和真实室内空气基质中的酸性水溶液中输送到 BODIPY 探针。探针在两种情况下都显示出 HONO 的定量吸收，形成与亚硝酸盐反应观察到的相同产物，没有迹象表明来自环境 NO 或 NO ₂的干扰。因此，探头的化学和物理特性使其非常适合用于被动采样器，以从大气中选择性采样 HONO。