A comparison between MALDI-TOF mass spectrometry and HPAEC-PAD analysis of debranched starch

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS, was used in this study to determine chain length distribution of amylopectin, the main constituent of starch. The technique was compared with high-performance anion-exchange chromatography with pulsed amperometric detection, HPAEC-PAD, an established technique for this purpose. Starch from potato, wheat, and waxy maize was debranched with isoamylase and analysed using both techniques. MALDI-TOF MS is a faster and more sensitive technique and provides more detailed information on the molecular mass of the unit chains. A difference between chain length distribution for amylopectin from different sources was observed with both methods. In addition, removal of amylose was not necessary for MALDI-TOF analysis. However, the technique was less reproducible than HPAEC-PAD and overestimated the amount of longer chains.