Fast and highly accurate mass spectrometry-based processes for detecting particular nucleic acid molecules and sequences in the molecules are provided. Arrays of oligonucleotides for performing mass spectrometric analyses are provided. In one aspect, a solid support is provided that includes a plurality of single-stranded oligonucleotides immobilized thereon by a linker cleavable under conditions of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry; and matrix for performing MALDI mass spectrometry, wherein the support comprises a flat surface.