Unifying Passive Air Sampling with Paper Spray Ionization Mass Spectrometry for the Detection of Third-Hand Cigarette...

To mitigate human exposure to air pollutants amid the increasing chemicalization of daily life, simple and rapid monitoring methods are required. As individuals spend a significant portion of their time indoors, indoor air quality has become a critical factor affecting human health and is influenced by a wide range of indoor and outdoor pollution sources. The sorption and desorption of indoor air pollutants on solid surfaces (the so-called sink effect) can gradually increase pollutant concentrations and lead to changes in indoor air quality. In particular, third-hand smoke (THS), a persistent form of indoor pollution, poses potential health risks through inhalation, dermal contact, and ingestion. Air sampling and analysis can be tedious and costly. Here, we present a very simple method that unifies passive sampling of THS onto paper and subsequent analysis by paper spray ionization (PSI) mass spectrometry (MS). Mass spectrometric results revealed the presence of nicotine, a major constituent of tobacco smoke, in THS samples collected using a custom-built passive sampler, which was further confirmed by MS/MS analysis. The applicability of this approach was further extended to a forensic context by detecting nicotine on book pages, which were previously exposed to cigarette smoke, using filter papers as sampling media. Overall, passive air sampling onto paper─combined with PSI-MS─provides a simple, cost-effective, and time-efficient way for indoor air quality monitoring and forensic analysis.