MATRIX-ASSISTED LASER-DESORPTION IONIZATION OF OLIGONUCLEOTIDES WITH VARIOUS MATRICES

Ferulic acid, 3-hydroxypicolinic acid (3-HPA), and 2,5-dihydroxybenzoi c acid (2,5-DHB) were used as matrices in MALDI of various oligonucleo tides. It was found that 2,5-DHB is an excellent matrix for polydeoxyr ibothymidylic acid. A poly-T oligonucleotide with a size of 130 bases was successfully detected. 3-HPA was found to be a good matrix for MAL DI of homo-oligomeric deoxynucleotides as well as those containing fou r different bases. Parent ions of pd(A)60, d(T)100, d(G)40, and d(C)40 were observed, and a mixed-base oligonucleotide of 150-mer was also d etected. Polymer ions of poly-A as large as 420-mer were measured; how ever, the efficiency for detecting poly-T with 3-HPA as a matrix was s lightly worse than when 2,5-DHB was used. Comparisons of three matrice s for various oligonucleotides is also presented.