John D. Naworal

Direct introduction of cigarette smoke for puff-by-puff trace metals analysis by inductively coupled plasma mass spectrometry

Puff-by-puff on-line analysis of trace metals in mainstream cigarette smoke has been developed by introduction of an aliquot of smoke aerosol directly into an inductively coupled plasma mass spectrometer (ICP-MS) by consecutively puffing a burning cigarette. An automated apparatus consisting of a series of solenoid valves was designed and built, interfacing a smoking machine with an ICP-MS for smoke generation, collection, injection, and analysis. Air, rather than argon, was used as the sample carrier gas to minimize the temporal changes in the plasma characteristics when a discrete smoke aerosol was introduced into the plasma. The measurement precision for the system was about 2.3% RSD (n = 9) for an ambient air sample, based on the peak area of 129Xe+, in comparison with the 10–50% RSD for the analytes in the smoke matrix sample. The temporal ICP-MS signal profiles behaved differently between analytes in terms of peak growth and decay patterns, which was attributed to differences in their physical forms. For the delivery of trace metals between puffs, As, Cd, and Pb appeared to increase in the later puffs as the cigarette was smoked. In contrast, the lighting puff had more Hg than the next few puffs. The relative deliveries of As, Cd, Hg and Pb in mainstream smoke between two reference cigarettes, 1R4F and 2R4F, were compared with those measured by the conventional methods and showed good agreement. This suggests that the trace metals concentration in cigarette smoke for any test cigarettes can possibly be determined, semi-quantitatively or even quantitatively, by comparison of their signal intensities with those obtained from a reference cigarette with known trace metals concentration in its cigarette smoke.

A rapid method for the determination of mercury in mainstream cigarette smoke by two-stage amalgamation cold vapor atomic absorption spectrometryPresented at 55th Tobacco Science Research Conference, Greensboro, NC, USA, September 2001.

A rapid method for the determination of mercury in mainstream cigarette smoke was developed utilizing reusable gold–platinum gauze to collect vapor phase mercury. Either an electrostatic precipitator or a Cambridge filter is used to remove the particulate phase of cigarette smoke, followed by a second Cambridge filter to further absorb volatile organic components. The vapor phase mercury is selectively trapped onto the gold–platinum gauze and is then determined by two-stage amalgamation cold vapor atomic absorption spectrometry (CVAAS) without matrix interference. One of the major advantages of this method is the avoidance of lengthy sample preparation procedures, which are required when using liquid impinger traps. Only one cigarette is required for smoke generation because of the preconcentration of mercury before quantitation and the enhanced sensitivity of amalgamation CVAAS. The limit of detection is 0.04 ng. The analytical precision of elemental mercury nis 6% at 0.1 ng and 0.3% at 10 ng in terms of relative standard deviation. For the 1R4F reference cigarette smoked under the FTC smoking regime and an alternative smoking regime, the vapor phase mercury in the mainstream smoke is 5.0 ± 0.4 ng per cigt (n n= 20) and 7.4 ± 0.4 ng per cigt (n n= 10), respectively. The recovery of fortified sample matrix is 97 ± 8% n(n n= 5) for FTC smoking regime and 96 ± 4% n(n n= 5) for the alternative smoking regime. The analytical results of the 1R4F reference cigarette were in good agreement with those obtained by the conventional liquid impinger method.