3-Aminopicolinic acid as a matrix for laser desorption mass spectrometry of biopolymers.

3-Aminopicolinic acid (3-APA) was tested and found to be a useful matrix for matrix-assisted laser desorption/ionization of DNA and protein. Single-stranded DNA segments of 150-mer and double-stranded DNA of 246 base pairs were successfully detected by using 3-APA as an ultraviolet-absorbing matrix in a linear time-of-flight mass spectrometer. In the case of the double-stranded DNA, only parent ions corresponding to single-stranded DNA were observed. The comparison with 3-hydroxypicolinic acid and picolinic acid matrices is discussed.