“…After simple pretreatment by ultrasonic extraction or microwave digestion, heavy metal species trapped on Cambridge filter can be transferred into a solution. The analysis of heavy metals could be facilitated by various analytical methodologies, including ion chromatography [27], differential pulse anodic stripping voltammetry [28], atomic absorption spectrometry [29,30] and inductively coupled plasma-mass spectrometry (ICP-MS) [31][32][33][34]. Due to the high sensitivity as well as the capability of multi-element determination, ICP-MS has become most attractive for the determination of trace heavy metal species in tobacco products.…”