Time-of-Flight Mass Spectrometry Of Underivatized Single-Stranded DNA Oligomers by Matrix-Assisted Laser Desorption

摘要: Matrix-assisted laser desorption with concomitant ionization (MALDI) in conjunction time-of-flight mass spectrometry (TOF-MS) has been used to analyze underivatized random-base single-stranded DNA (ssDNA) oligomers ranging from 10 89 nucleotides length by embedding them a solid matrix of 3-hydroxypicolinic acid. At 355-nm wavelength, spectra positive and negative ions measured reflecting linear spectrometers are compared. Results the system show yield is approximately equal for each polarity. Metastable ion decay significant larger ssDNA oligomer ions, which results decrease signal intensity broadening peaks. In order obtain an acceptable signal-to-noise ratio on TOF system, higher irradiance needed, consequently causes further degradation resolution. With apparent advantages better sensitivity resolution, it concluded that suited spectrometric analysis than about 25-mer. The current permits one-base resolution up 40-mer. Mass accuracy 20-mer or smaller within +/- 0.05%. Comparison 5-ns 35-ps pulse widths at same energy density shows no differences. Mechanisms oligonucleotide production these experiments discussed.