High-performance liquid chromatography LTQ-Orbitrap mass spectrometry method for tomatidine and non-target metabolites quantification in organic and normal tomatoes

Tomatoes, members of the Solanaceae plant family, produce biologically active secondary metabolites, including glycoalkaloids and aglycons, which may have both adverse and beneficial biological effects. A new liquid chromatography method that utilized LTQ-Orbitrap MS was developed for the analysis of tomatidine, the main aglycon in tomatoes. Recoveries of tomatidine were >98.3% with the relative standard deviations (RSDs) below 6.1%. The limit of detection (LODs) was 0.0003 mg kg−1. The limit of quantitation (LOQs) is 0.001 mg kg−1. The linear range was between with 0.0025 and 1 mg kg−1 with an excellent correlation coefficient (R2) equal to 0.9990. Various tomato samples were analyzed and the level of tomatidine in the 11 samples analysed was higher in normal respect to organic tomatoes. The capability of the set-up Full Scan LTQ-Orbitrap MS method allowed us to quantified two non-target analytes. The m/z 1032 was identified as dehydrotomatine, confirmed through accurate mass studies (mass error in ppm equal to 1.5017) meanwhile m/z 902 as (Glc)2–Gal-Tomatidine (β1-Tomatine) (mass error in ppm equal to 2.0719).