Figure 4
Measurement of carbon monoxide concentrations using a ‘direct’ and ‘indirect’ technique following a 16 minute ISO smoke run using 3R4F reference cigarettes at airflows 1.0, 4.0, 8.0 and 12.0 L/min [a] and reciprocal airflow (1/ airflow (L/min)) of; 1.0, 0.25, 0.125 and 0.080 respectively [b], with a vacuum of 5 ml/min/well. Results are based on three independent experiments per airflow. [a] Shows an individual value plot of obtained for CO concentrations (μg/ml) and comparisons of concentrations obtained using two independent techniques, one real time and direct technique and one indirect gas-bag technique. For airflows 1.0, 4.0, 8.0 and 12.0 L/min using the direct technique CO concentrations were, 0.8 ± 0.2, 0.3 ± 0.01, 0.2 ± 0.01, and 0.1 ± 0.005 μg/ml and using the indirect technique, CO concentrations of 1.4 ± 0.1, 0.4 ± 0.04, 0.1 ± 0.01, and 0.1 ± 0.01 μg/ml were obtained respectively. [b] Shows data presented as a reciprocal of the airflow (1/airflow (L/min)) with a regression fit correlation of R2 = 0.921 for the direct and R2 = 0.987 for the indirect technique.