Determination of sialic acids in infant formula by liquid chromatography tandem mass spectrometry.
A liquid chromatographic/tandem mass spectrometric method using pneumatically assisted electrospray ionization (LC-ESI-MS/MS) was developed for determination of N-acetylneuramic acid and N-glycolylneuramic acid in infant formula. Reconstituted samples were hydrolysed in dilute sulfuric acid and deproteinized with acetonitrile. The extract was analysed directly without further clean-up by hydrophilic interaction chromatography. The substances were detected in negative ion mode and matrix matched standards were used for calibration. The relative intra-laboratory reproducibility standard deviation was better than 6% for both substances. An R² of 0.985 was obtained by comparison with a classical colorimetric assay based on reaction with resorcinol. The developed method is expected to be applied for accurate routine analysis of infant formulas.
Eurofins Steins Laboratorium, Hjaltesvej 8, 7500 Holstebro, Denmark. lks@eurofins.dk
L K
LK
Sørensen
D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D041943:Infant Formula / Q000737:chemistry*; D012794:Sialic Acids / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods*
D012794:Sialic Acids