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.
Sørensen
L K
LK
Eurofins Steins Laboratorium, Hjaltesvej 8, 7500 Holstebro, Denmark. lks@eurofins.dk
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