Characterisation of the volatile profiles of infant formulas by proton transfer reaction-mass spectrometry and gas chromatography–mass spectrometry

The volatile profiles of 13 infant formulas were evaluated by proton transfer reaction-mass spectrometry (PTR-MS) and gas chromatography–mass spectrometry (GC–MS). The infant formulas varied in brand (Aptamil, Cow & Gate, SMA), type (for different infant target groups) and physical form (powder/liquid). Fingerprint mass spectra were obtained from the headspace of the samples using PTR-MS. GC–MS was used to identify the volatile compounds. Brand, type and physical form of the infant formulas had a significant effect on the volatile profiles measured by PTR-MS. Forty-two masses were significantly affected by the brand, 14 by the type of formula, and 40 by the physical form. Eleven masses were among the most abundant across all samples (mass m/z 43, 45, 49, 55, 59, 60, 63, 69, 73, 83, and 87). Gas chromatography–mass spectrometry revealed the identity of 28 of the volatile compounds of the infant formulas. Most of the masses detected in PTR-MS were related to compounds identified by GC–MS.