TY - JOUR
T1 - Improving spot homogeneity by using polymer substrates in matrix-assisted laser desorption/ionization mass spectrometry of oligonucleotides
AU - Kim, Y.
AU - Hurst, G. B.
AU - Doktycz, M. J.
AU - Buchanan, M. V.
PY - 2001/6/1
Y1 - 2001/6/1
N2 - We describe a method for improving the homogeneity of MALDI samples prepared for analysis of small, single-stranded oligonucleotides using the widely used DNA matrix system, 3-hydroxypicolinic acid/picolinic acid/ammonium citrate. This matrix system typically produces large crystals around the rim of the dried sample and requires tedious searching of this rim with the laser. However, when a substrate is prepared using both Nation and a hydrophilic, high-molecular-weight polymer, such as linear polyacrylamide, linear poly(ethylene oxide), or methyl cellulose, oligonucleotide-doped matrix crystals tend to be smaller and more uniformly distributed across the entire spot, thus decreasing the time that is required for locating a usable signal. In addition to MALDI characterization of the spatial distribution of "sweet spots," fluorescence microscopy allows for imaging dye-labeled DNA in dried MALDI spots. The mechanism of enhanced uniformity may involve increased viscosity in the MALDI sample droplet due to partial solubilization of the substrate by the MALDI sample solvent as well as partitioning of the matrix or DNA between the solvent and the undissolved portion of the polymer substrate.
AB - We describe a method for improving the homogeneity of MALDI samples prepared for analysis of small, single-stranded oligonucleotides using the widely used DNA matrix system, 3-hydroxypicolinic acid/picolinic acid/ammonium citrate. This matrix system typically produces large crystals around the rim of the dried sample and requires tedious searching of this rim with the laser. However, when a substrate is prepared using both Nation and a hydrophilic, high-molecular-weight polymer, such as linear polyacrylamide, linear poly(ethylene oxide), or methyl cellulose, oligonucleotide-doped matrix crystals tend to be smaller and more uniformly distributed across the entire spot, thus decreasing the time that is required for locating a usable signal. In addition to MALDI characterization of the spatial distribution of "sweet spots," fluorescence microscopy allows for imaging dye-labeled DNA in dried MALDI spots. The mechanism of enhanced uniformity may involve increased viscosity in the MALDI sample droplet due to partial solubilization of the substrate by the MALDI sample solvent as well as partitioning of the matrix or DNA between the solvent and the undissolved portion of the polymer substrate.
UR - http://www.scopus.com/inward/record.url?scp=0035356943&partnerID=8YFLogxK
U2 - 10.1021/ac001392v
DO - 10.1021/ac001392v
M3 - Article
C2 - 11403308
AN - SCOPUS:0035356943
SN - 0003-2700
VL - 73
SP - 2617
EP - 2624
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 11
ER -