Recommendations for quantitative analysis of small molecules by matrix-assisted laser desorption ionization mass spectrometry

Abstract

Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) has been used for quantitative analysis of small molecules for many years. It is usually preceded by an LC separation step when complex samples are tested. With the development several years ago of "modern MALDI" (automation, high repetition laser, high resolution peaks), the ease of use and performance of MALDI as a quantitative technique greatly increased. This review focuses on practical aspects of modern MALDI for quantitation of small molecules conducted in an ordinary way (no special reagents, devices or techniques for the spotting step of MALDI), and includes our ordinary, preferred methods The review is organized as 18 recommendations with accompanying explanations, criticisms and exceptions.

Keywords: MALDI-MS; Ordinary conditions; Quantitative analysis; Recommendations; Sample spotting; Small molecules.

Figure 1

Relative final peak intensities of analytes 1-4 subjected to analysis by MALDI-MS in six samples (colored bars), where the matrix was CCA; the reference peak (at m/z 172) for relative quantitation was protonated CCA – H₂O; and the number of trial spectra for each peak was three.