Simultaneous identification and quantification of the sugar, sugar alcohol, and carboxylic acid contents of sour cherry, apple, and ber fruits, as their trimethylsilyl derivatives, by gas chromatography-mass spectrometry.

Our gas chromatography-mass spectrometry method--developed for the simultaneous quantitation of mono-, di-, and trisaccharides, sugar alcohols, caboxylic and amino acids, measured as their trimethylsilyl-(oxime) ether/ester derivatives, from one solution by a single injection, prepared in the presence of the fruit matrix--has been extended/utilized for special purposes. The compositions of (i) freshly harvested and stored sour cherries (Prunus cerasus), (ii) apples obtained from organic and integrated productions (Malus domestica), and (iii) green and ripe bers (Zizyphus mauritiana L.) were compared. On the basis of earlier, basic researches (derivatization, quantitation, and fragmentation studies of authentic compounds), we demonstrate the reproducible quantitation of the main and minor constituents in a wide concentration range (approximately 1 x 10(-)(3) to >/=40%, in total up to < or =98%, calculated on dry matter basis of the fruit matrices). Reproducibility of quantitations, calculated on the basis of their total ion current values, provided an average reproducibility of 3.3 (sour cherries), 6.2 (apple), and 4.3 (ber) RSD %, respectively.