Matrix-assisted laser desorption/ionization mass spectrometry methods for oligodeoxynucleotides: improvements in matrix, detection limits, quantification, and sequencing.

A comatrix of anthranilic acid and nicotinic acid is optimum for the matrix-assisted laser desorption/ionization time of flight determination of oligodeoxynucleotides that are comprised of up to 21 nucleotides. A detection limit of approximately 200 amol was obtained for an oligonucleotide 21mer. The comatrix system is also suitable for quantification of oligodeoxynucleotides provided an internal standard having one more or less nucleotide than the number in the analyte is used. Furthermore, the matrix, when used in combination with the ladder method of sequencing, allows the complete sequence of tens of picomoles of model oligodeoxynucleotides to be determined.