Abstract：
Dry hitting, a phenomenon produced by e-cigarettes with refillable cartridges when the liquid in the coil is low, is a common occurrence among regular vapers despite being an unintended consequence of the device. This phenomenon\'s hazard to public health is still unknown and needs further investigation. Lung cells cultured at the air-liquid interface were exposed to vaped aerosol consisting of 3 % w/v ethyl maltol in propylene glycol for three-second puffs every 30 seconds for 80 total puffs with either dry hit or saturated conditions. Cytotoxicity was measured colorimetrically. The thermal degradation of the heating coils and wicks was visualized using scanning electron microscopy. The chemical byproducts in the aerosol were analyzed using proton nuclear magnetic resonance and inductively coupled plasma mass spectrometry. The results revealed a highly significant increase in cytotoxicity from dry hit treatments. Imaging showed thermal decomposition of the cotton wick after dry hitting, which was confirmed by energy dispersive x-ray spectroscopy with less oxygen in the dry hit cotton. Chemical byproducts were found via unique peaks in the dry hit condensate in the aromatic and alkene regions. Saturated condensate showed higher concentrations of detected metal species than dry-hit condensate. E-cigarette users should avoid dry hitting by refilling tanks or cartridges preemptively or by using disposable coils to avoid increased toxicity during vaping.
摘要：
干击，当线圈中的液体较低时，具有可再填充墨盒的电子烟产生的现象，尽管是该设备的意外后果，但在常规蒸气中却很常见。这种现象对公众健康的危害尚不清楚，需要进一步调查。将在气液界面处培养的肺细胞暴露于由3％w/v乙基麦芽酚在丙二醇中的蒸气气溶胶中，每30秒抽吸三秒钟，在干燥或饱和条件下进行80次总抽吸。比色法测量细胞毒性。使用扫描电子显微镜观察加热线圈和芯的热降解。使用质子核磁共振和电感耦合等离子体质谱法分析了气溶胶中的化学副产物。结果揭示了来自干撞击处理的细胞毒性的高度显著增加。成像显示棉芯在干击后热分解，这是通过能量色散x射线光谱法证实的，干打棉花中的氧气较少。通过芳烃和烯烃区域的干击冷凝物中的独特峰发现了化学副产物。饱和冷凝物显示检测到的金属物种的浓度高于干击冷凝物。电子烟使用者应避免通过预先填充水箱或墨盒或使用一次性线圈来避免干击，以避免在vaping期间增加毒性。
