[Analysis of phthalate esters and their novel alternatives in indoor dust using comprehensive two-dimensional gas chromatography-time of flight mass spectrometry].

A comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS) method was developed to analyze 25 traditional phthalate esters (PAEs) and 19 novel alternatives in indoor dust samples. PAEs are ubiquitous in indoor environments because they are widely used as plasticizers in a variety of consumer products, and potential health concerns have prompted the need for effective monitoring methods. In this study, dust samples were collected from various indoor settings in a university campus, including classrooms, cafeterias, laboratories, and dormitories, and were subsequently ultrasonically extracted with hexane-dichloromethane (1∶1, v/v) solution for 30 min. This method was chosen to maximize PAE recovery while minimizing potential interference from other compounds present in the dust matrix. Compounds were separated on a Rix-5MS column (30 m×0.25 mm×0.25 μm) as the first dimension, with a Rix-17Sil column (1.39 m×0.25 mm×0.25 μm) serving as the second dimension. The following temperature program was used: 60 ℃ for 1 min, then increasing to 220 ℃ at 20 ℃/min, followed by a further increase to 290 ℃ at 5 ℃/min, with the final temperature held for 8 min; this program was optimized to afford maximum target-compound resolution and sensitivity. The developed method rapidly, accurately, and sensitively detected the target PAEs and their alternatives under the optimal conditions, which included a carrier-gas flow rate of 1.4 mL/min, a modulation period of 4 s, and an injection-port temperature of 250 ℃. The 44 target compounds exhibited highly linear calibration curves across a content range of 1-500 μg/g, with all correlation coefficients exceeding 0.99. The limits of detection (LODs) of the method were determined to lie between 0.57 and 13.0 ng/g, which reflects the high sensitivity of the developed approach. At spiked levels of 1, 10, and 50 μg/g, the recoveries of the analyzed compounds varied from 72.8% to 125%, with relative standard deviations ranging from 1.29% to 14.8% (