Abstract: A method for determining volatile organic compounds (VOCs) emitted from medical molecular sieve oxygen concentrators was developed using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The oxygen concentrator gas was sampled at a flow rate of 0.5 L/min through a branched sampling system onto Tenax GR/Carbopack B adsorption tubes. The adsorbed compounds were desorbed and introduced via a programmed temperature vaporization inlet system, followed by chromatographic separation on an SH-I-624Sil MS column. Four VOCs (BHT-Q, PTBP, BHT-quinol, and EHB) were detected in the medical oxygen concentrator using this method. Calibration curves for these compounds exhibited excellent linearity (R²>0.99) within the range of 3~100 ng. With a sampling volume of 20 L, the detection limit of the four VOCs ranged from 0.003 9 to 0.022 2 μg/m³. Spike recovery rates for the four VOCs were between 95% and 115%, with relative standard deviations (RSDs) below 5% (n=6). The method is simple, rapid, highly sensitive, and accurate, making it suitable for VOC detection in medical molecular sieve oxygen concentrators.