Abstract: An analytical method was developed for the simultaneous determination of tomatine and tomatidine in tomatoes by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Samples were homogenized, separated on a Proshell 120 EC-C18 column, and purified by solid phase extraction (SPE) with C18 as sorbent and tomatine and tomatidine were then analyzed by triple quadrupole tandem mass spectrometry under the multiple reaction monitoring (MRM) mode. The mobile phase consisted of 5 mmol/L ammonium acetate (containing 0.05% formic acid) and acetonitrile. The results showed that good linearity was observed for tomatine and tomatidine with correlation coefficients above 0.999 1 and 0.999 4 in the range of 50–1 000 and 5–100 ng/mL, respectively. The average recoveries at three spiked levels ranged from 85.6% to 105%, with relative standard deviations (RSDs) varying from 1.0% to 6.8%. The developed method was simple and rapid with high sensitivity and repeatability, which was suitable for rapid and simultaneous determination of tomatine and tomatidine in tomatoes. Tomatine was significantly more abundant than tomatidine in tomato samples as determined by this method.

Key words: tomato, tomatine, tomatidine, high performance liquid chromatography-tandem mass spectrometry