Matrix-Assisted Laser Desorption/Ionization-Fourier Transform Mass Spectrometry (MALDI-FTMS) is an emerging method for kinetic measurements and inhibitor screening of acetylcholinesterase (AChE). This method is accurate, reproducible, and was successfully applied to the analysis of various biosamples. Recent studies showed the important biological functions of acetylcholinesterase in many kinds of tumors caused by smoking; however, the effect of cigarette smoke condensates (CSCs) on AChE was unclear. Herein, the effects of CSCs on AChE activity in human lung epithelial cells were studied by MALDI-FTMS. The results showed that AChE activity in human lung epithelial cells could be inhibited by CSCs, and inhibition degree on AChE activity depended on the amount of CSCs. Owing to the close relationship of AChE to lung cancer caused by smoking, such findings provide information regarding the relation between the aggressiveness of lung tumor and cigarette smoking.
For fast and accurately determining the tobacco-specific nitrosamines (TSNAs) in mainstream cigarette smoke,the test for improving the determining conditions of liquid chromatography-tandem mass spectrometry was conducted.The results showed that: 1) 10 mmol/L of ammonium acetate solution could replace 100 mmol/L of ammonium acetate solution as an extractant;2) the sample extraction could be directly analyzed by LC-MS/MS after it was filtered by 0.45 μm membrane; 3) more accurate quantitative results were obtainable by simultaneously using NNN-d4,NNK-d4,NAT-d4,and NAB-d4 as internal standards;4) the recoveries of the TSNAs ranged from 91% to 100.6% with the RSDs of 0.76% to 5.42% and the limits of detection of 0.06 to 0.14 ng/mL.The method can be used to determine the contents of TSNAs in mainstream smoke of Virginia or blended type cigarettes.
A simulated chewing machine was developed for evaluating in vitro the release behavior of nicotine from gum-based smokeless tobacco products,and the in vitro nicotine release rates from four kinds of gum-based tobacco products on the market were tested by combining that machine with HPLC.The chewing machine was mainly composed of a container for solvent,two peristaltic pumps,a thermostat,two circulating water tanks,a sample stage,an air compressor,a cylinder,a motor,a pneumatic clamp and a liquid collector.The test chamber formed by the circulation tanks and sample stage simulated a buccal cavity,which ensured nicotine release at a constant temperature of 37 oC into artificial saliva,the pneumatic clamp pushed by the air compressor compressed the test sample repeatedly simulating the chewing action.The in vivo and in vitro nicotine release tests showed that evaluating the release behavior of nicotine from gum-based tobacco products with the simulated chewing machine was simple and reliable,the test results were close to the nicotine release from gum-based tobacco products taken by a human being.The technique was of practical uses for the quality control of gum-based tobacco products,the evaluation of nicotine bioavailability as well as the control of nicotine.
A simple method was established for the rapid determination of low molecular carbonyl compounds by the combination of atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) and data mining. The ionization was carried out in positive mode, and six low molecular carbonyl compounds of acrolein, acetone, propionaldehyde, crotonaldehyde, butanone, and butyraldehyde were analyzed by both full scan mode and daughter scan mode. To overcome the quantitative difficulties from isomer of acetone/propionaldehyde and butanone/butyraldehyde, the quantitation procedure was performed with the characteristic ion of [CH 3 O] + under CID energy of 5 and 15 eV. Subsequently, the established method was successfully applied to analysis of six low molecular carbonyl compounds in tobacco smoke with analytical period less than four minutes. The contents of acrolein, acetone, propionaldehyde, crotonaldehyde, butanone, and butyraldehyde for a cigarette were about 63±5.8, 325±82, 55±9.7, 11±1.4, 67±5.9, and 12±1.8 μ g/cig, respectively. The experimental results indicated that the established method had the potential application in rapid determination of low molecular carbonyl compounds.
A method based on liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of four tobacco-specific N-nitrosamines(TSNAs) in gum-based tobacco products.Using NNN-d4,NNK-d4,NAB-d4,NAT-d4 as internal standards,samples were successively extracted with 0.05 mol/L HCl aqueous solution,cleaned up by HLB solid phase extraction cartridge,separated by an Agilent Poroshell 120 SB-C18 column,and analyzed by a tandem mass detector under multi-reaction monitoring(MRM) scan mode.The results showed that: 1) the limits of quantification of TSNAs varied from 0.026 to 0.076 ng/mL,the recoveries ranged from 80.00% to 126.86% and relative standard deviation(RSD) from 2.99% to 8.32%;2) the total concentration of TSNAs ranged from 5.13 to 13.76 ng/g.The concentrations of NNN and NAT were much higher and their sum accounted for 91.23% to 95.71% of total TSNAs yields.The method is fit for the simultaneous analysis of TSNAs in gum-based tobacco products.
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