Matrix 3-hydroxypicolinic acid

The success of the analysis of oligonucleotides is strongly dependent on the choice of the matrix and the preparation of the sample. A major improvement has resulted from the introduction of new matrices specific for the oligonucleotides. An example is 3-hydroxypicolinic acid. [165] Several strategies for sample preparation have been adopted, with the principal goal of eliminating interference from the ubiquitous alkali metal ions a combination of the use of cation exchange columns to replace the alkali metal ions by ammonium and the addition of some ammonium salt to the sample. 

J. Wu, A. Sterling, and C. H. Becker, Matrix-assisted laser desorption time-of-flight mass spectrometry of ohgonucleotides using 3-hydroxypicolinic acid as an ultraviolet-sensitive matrix. Rapid Commun. Mass Spectrom. 7, 142-147 (1993). 

Figure 5.3 Sections of UV MALDI mass spectra of 70, 80, and 90mer DNA strands desorbed from 3-3-hydroxypicolinic acid as a matrix and analyzed in an orthogonal TOF. The MALDI ions first pass a quadmpole before they enter a reflectron TOF section. Independent of the ion source used and the mass of the molecules, the O-TOF analyzer provides a constant instmmental resolution throughout the whole mass range rather than a mass-dependent resolution as in axial MALDI-TOF. The indicated full width at...

Equilibration solution 0.1 M triethylammonium acetate (TEAA), pH 7 Wash solution 1 0.1 TEA A, pH 7 Wash Solution 2 Nuclease-free water Matrix 9 parts of 50 mg/mL of 3-hydroxypicolinic acid (3-HPA) in 50% ACNAVater, 1 part of ammonium acetate in nuclease free water... 

Figure 20 DE-MALDI-TOF spectrum of a mixture of Sanger dideoxy DNA sequencing reactions containing about 0.1 pmol of each termination fragment generated by primer extension on a 50-base-pair template. The matrix used was a mixture of of 3-hydroxypicolinic acid and picolinic acid including diammonium citrate to complex metal ions (prepared according to Wu et al. [98]). The four panels correspond to termination with (A) ddA. (B) ddC, (C) ddG, and (D) DDT. (From Ref. 82.)...

MALDI matrix used for antibody detection a-Cyano-4-hydroxycinnamic acid (HCCA) and 3-hydroxypicolinic acid (3-HPA) (Sigma-Aldrich). 

Nicotinic add (NA) was the first organic compound to be successfully employed as a matrix in UV-MALDI of peptides and proteins [12-14]. Ever since, better matrices have been sought, the following now being widespread in use (Fig. 11.8) picolinic acid (PA) [67], 3-hydroxypicolinic acid (HPA) [68], 3-aminopicolinic add (3-APA) [69], and 6-aza-2-thiothymine (ATT) [70,71] for oligonucleotides... 

Wu, K.J. Steding, A Becker, C.H. Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry of Oligonucleotides Using 3-Hydroxypicolinic Acid As an Ultraviolet-Sensitive Matrix. Rapid Commun. Mass Spectrom. 1993, 7, 142-146. 

A major difference between ESI and MALDI is that ESI requires liquid samples whereas MALDI, so far, works best with crystalHne samples. Another important difference is that MALDI requires a special matrix compound for the analysis of biological macromolecules, e.g., a-cyano-4-hydroxycinnamic acid (CHCA) for small and medium-size peptides, sinapic acid (SA) for large peptides and proteins, 2,5-dihydroxybenzoic acid (DHB) for glycosylated peptides and proteins, and 3-hydroxypicolinic acid for nucleic acids. It is noteworthy that all these compounds have been found solely empirically and that only a very few out of many hundred candidates turned out to be successful. 

The energetics of matrix ion autoionization reactions are important reference values in MALDI. Some calculated examples are (DHB = 2,5 dihydroxybenzoic acid, 3HPA = 3 hydroxypicolinic acid, NA = nicotinic acid, G = glycerol) ... 

PtiRETZKY, A. A. Geohegan, D. B. Gas-phase diagnostics and LIF imaging of 3-hydroxypicolinic acid MALDI matrix plumes. Chem. Phys. Lett. 1997, 286, 425-132. 

Further performance improvements in analysing nucleic acids could be achieved by the introduction of 3-hydroxypicolinic add as matrix [8] and the introduction of delayed extraction in a linear time-of-flight mass spectrometer [9]. If, for MALDI Fourier transform mass spectrometry, the molecular weight range in analysing nucleic add fragments could be extended further this type of MALDI MS would become of significant value due to the extraordinary resolution possible [10, 11]. In order to reach the sensitivity level necessary for MALDI-TOF MS analysis an amplification step has to be incorporated into the sample preparation process for... 

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