Hindered amine light stabilizers in indoor dust: method development and occurrence

Hindered amine light stabilizers (HALS) are polymer additives extensively used to improve the durability of plastic materials by inhibiting degradation induced by ultraviolet radiation. Due to their effectiveness, HALS are incorporated into a wide variety of polymeric products intended for both indoor and outdoor applications. However, because these compounds are not chemically bound to the polymer, they can be released into the environment through processes such as volatilization, abrasion, and dissolution. As a result, HALS may accumulate in dust and other environmental matrices. Their occurrence in indoor and outdoor dust raises concerns regarding environmental persistence and potential human exposure, underscoring the need for robust and sensitive analytical methods for their determination. In this study, a new analytical methodology for the determination of HALS in dust samples was developed and optimized. Different sample preparation techniques, including matrix solid-phase dispersion (MSPD), pressurized liquid extraction (PLE), and ultrasound-assisted extraction (UAE), were evaluated with the aim of improving extraction efficiency while minimizing matrix effects. Quantitative analysis was performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) equipped with a triple quadrupole (QqQ) mass analyzer, providing high sensitivity and selectivity. The optimized procedure was subsequently applied to dust samples collected from various indoor environments to investigate the occurrence and distribution of HALS. These findings contribute to a better understanding of HALS contamination in dust and associated human exposure pathways.