A determination of aromatic amines in tobacco by Solid Phase Extraction and High Performance Liquid Chromatography
A new method for the determination of aromatic amines (aniline, p-methylaniline, 2,4-dimethylaniline, 2,4,6-trimethylaniline, 1-naphthylamine, 2-naphthylamine) in tobacco by solid phase extraction and high performance liquid chromatography (HPLC) is described. Using solid phase extraction, the purification and enrichment for trace aromatic amines in tobacco could be accomplished efficiently and quickly. Application of the Photodiode Array Detector (PAD) offered a high sensitivity and more reliable qualitative analysis. Potential interference of alkaloids in the determination of aromatic amines was eliminated by using highly selective pre-column derivatization for the aromatic amines. Aromatic amines were extracted from tobacco samples by steam distillation, then were pre-column derived with 1-naphthol to form azo dyes. The azo dyes were enriched by solid phase extraction with a Waters Sep-Pak-C18 cartridge and separated on a Waters XterraTM RP18 chromatographic column (3.9´150 mm), with 82% methanol (containing 0.01 mol/L pyrrolidine-acetic acid buffer solution (pH8)) as mobile phase at a flow rate of 0.5 ml/min. Each aromatic amine was monitored at its maximum absorption wavelength by PAD, aniline 473 nm, p-methylaniline 468 nm, 2,4-dimethylaniline 464 nm, 2,4,6-trimethylaniline 462 nm, 1-naphthylamine 496 nm, 2-naphthylamine 494 nm. The detection limits ranged from 30 to 50 µg/L. The determinations of the above aromatic amines were performed by a calibration curve method. The recoveries of aromatic amines ranged from 92 to 106%. The relative standard deviations ranged from 1.8 to 2.4%. This method can be successfully applied to the determination of trace aromatic amines in tobacco.