Mainstream Smoke Collection by Electrostatic Precipitation for Acid Dissolution in a Microwave Digestion System Prior to Trace Metal Determination

Abstract

A method is described for collection and preparation of mainstream smoke condensate from cigarettes for determination of trace metal constituents. A sample of mainstream smoke was collected from 300 cigarettes in a final volume of 25 mL. Extremely clean laboratory conditions during sample preparation were essential to avoid contamination and improve precision and accuracy for trace element determination. The clean laboratories maintained a positive pressure of HEPA-filtered air with constant temperature and humidity control. Mainstream cigarette smoke was collected by electrostatic precipitation (EP) on a modified rotary smoking machine located in a wooden CORESTA cabinet. The EP unit was equipped with a high tension generator supplying 17.5 kV to a tungsten electrode followed by 2 secondary acid traps. Samples were collected under 2 smoking regimens: FTC (35 mL puff volumes, one puff every 60 s, and puff duration 2 s) and “Extreme” (75 mL puff volumes, one puff every 35 s, puff duration 2 s). Condensate was extracted from collection tubes with methanol into Teflon microwave digestion vessels and evaporated in an environmental evaporation chamber (EEC). The EEC provided an ultraclean environment for sample evaporation and predigestion steps that eliminated most of the sample matrix. The remainder was decomposed in a programmable closed vessel microwave digestion system. Digested sample solutions were analyzed by graphite furnace atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry for aluminum, arsenic, cadmium, chromium, nickel, and silicon.

Toxicological evaluation of an electrically heated cigarette. Part 2: Chemical composition of mainstream smoke

“…Our resulting LIST (List of Important Substances in Tobacco Smoke) contains 60 smoke constituents (Voncken et al, 1998), including key constituents representative of various chemical classes, and most of the smoke constituents on the other proposed smoke chemistry lists (Borgerding et al, 1997;Rhoades and White, 1997;and Vorhees et al, 1997) with an overlap of approximately 70% or more. Although some of the smoke constituents on the LIST were not determined in this work because their method development is still in progress in our laboratory, some additional constituents were determined either because they occur in one chromatographic run together with selected constituents (e.g.…”