Determination of 4 Aromatic Amines in Mainstream Cigarette Smoke by Heart-Cutting Two Dimensional Liquid Chromatography-Tandem Mass Spectrometry

A method for the determination of 4 aromatic amines, including 1-amino-naphthalene (1-NA), 2-amino-naphthalene (2-NA), 3-aminobenzene (3-ABP), 4-aminobenzene (4-ABP) in mainstream cigarette smoke by heart-cutting two dimensional liquid chromatography-tandem mass spectrometry (2DLC-MS/MS) was proposed. The particulate matter of 20 cigarettes smoke was collected with Cambridge filter, and 200 μL of 1 mg·L^-1 the mixed internal standard solution and 20 mL of 5% (mass fraction) hydrochloric acid solution were added for ultrasonic extraction for 30 min. An aliquot (10 mL) was taken, and 1 mL of 50% (mass fraction) sodium hydroxide solution was added to adjust the solution adicity to pH 7. Then 2 mL of dichloromethane was added, and the mixed solution was shaken by vortex for 15 min. The organic phase was filtered by 0.2 μm polytetrafluoroethylene filter membrane. A strong cation exchange (SCX) column was used in the first dimensional liquid chromatography to separate and remove impurities from the targets, the organic phase was diluted and neutralized online by compensation pump, and targets were retained in the trap column. Then the targets were eluted to the second dimensional reversed phase (RP) chromatography system, and the multiple reaction monitoring (MRM) mode of mass spectrometry detector was used, with internal standard method for quantitative analysis. It was shown that the linear ranges of the standard curves were 0.50-50.0 μg·L^-1 for 1-NA and 2-NA, and 0.25-50.0 μg·L^-1 for 3-ABP and 4-ABP, with detection limits in the range of 0.002-0.008 ng in a cigarette. The recovery of the 4 targets at 3 spiked concentration levels were in the range of 86.0%-97.4%. Tests for precision of intra-day and inter-day were made, with RSDs of determined values less than 8.0%. The samples of commercial Virginia type cigarettes and blended-type cigarettes were analyzed, and the determined value of aromatic amines in blended-type cigarettes presented positive linear relationship with the labeled tar value. No linear relationship was observed for Virginia type cigarettes.