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Determination of beef tallow in lard through a multidimensional off‐line non‐aqueous reversed phase–argentation LC method coupled to mass spectrometry
Author(s) -
Dugo Paola,
Kumm Tiina,
Fazio Alessia,
Dugo Giovanni,
Mondello Luigi
Publication year - 2006
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200500342
Subject(s) - chromatography , chemistry , mass spectrometry , aqueous solution , tallow , phase (matter) , analytical chemistry (journal) , organic chemistry
The presence of tallow in lard is not easy to determine, due to the similarity of the composition of these two animal fats, which differ mainly in the distribution of fatty acids (FA) in the three positions of the glycerol molecule. The determination of the composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtures was investigated by HPLC in combination with atmospheric pressure chemical ionization mass spectrometry (APCI‐MS). The presence of tallow in lard was determined through the study of the sn‐ POP/ sn‐ PPO ratio by multidimensional HPLC. The off‐line bidimensional system was attained through the coupling of non‐aqueous reversed phase (NARP)‐HPLC and silver ion (Ag)‐HPLC. The primary column eluate was fractionated and the fraction containing POP/PPO isomers was injected onto the secondary column, allowing the separation of positional isomers, unresolved in the first dimension. Peak assignment was carried out by combining retention data with APCI‐MS spectral information. The fatty acid distribution along the glycerol backbone, determined by Ag‐HPLC, was confirmed through diglyceride ion ratios derived from APCI‐MS analysis. Method validation was carried out in preliminary applications on standard TAGs. The analytical results obtained show that even a 5% addition of tallow to lard modifies the distribution of positional isomers.