Methods development for the characterization of mainstream bidi cigarette smoke and assessment of experiments for environmental analysis.

摘要

The main goal of the first part of this work is to characterize the constituents of bidi mainstream smoke using Fourier Transform infrared spectrometry (FTIR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS) techniques. For the educational component, the objective is to develop and assess the effectiveness of two environmental chemistry laboratory experiments, namely, "FTIR Analysis of Mainstream Cigarette Smoke" and "Extraction of Organic Pollutants from Soil Samples for GC-MS Analysis" for undergraduate students.; The gaseous portion of bidi mainstream smoke was found to contain 310 mug/cigarette of hydrogen cyanide via FTIR analysis while the GC-MS analysis of the sorbent tube extract indicated a higher concentration of 3-methylpyridine, cotinine, and nicotine in the mainstream smoke of bidi cigarette compared to that of the 1R5F reference cigarettes. The mainstream smoke of bidis also contained alpha/beta-amyrins that may have originated in the tendu leaves used to wrap the bidis, but these compounds were absent in the mainstream smoke of 1R5F reference cigarettes. Comparative analysis of the particulate phase of mainstream cigarette smoke by GC-MS indicated a higher concentration of nicotine in the bidi smoke compared to the 1R5F reference cigarette smoke. It was found that 85% of the nicotine present in the particulate phase of bidi cigarette smoke had particle size of less than 0.25 mum.; For the analysis of standard carbonyl-DNPH derivatives by GC-MS, an optimum injector temperature of 230°C was ideal for C1-C3 carbonyl derivatives, while 250°C was optimal for the C4-C6 derivatives. LC-MS was more suitable for the detection of carbonyl derivatives having greater than five carbon atoms, including aromatic aldehydes, compared to GC-MS. Both the GC-MS and LC-MS results revealed that acetaldehyde was present at the highest concentration among all the carbonyls detected in the bidi mainstream smoke.; For the educational part, assessment of the two laboratory experiments revealed that the experiments may be appropriate for enhancing students' understanding and the application of key spectroscopic and chromatographic concepts learned in class. Also, the use of real world samples and exposure to modern instruments could enhance students' enthusiasm about science and increase students' interest in research.