Author(s): Shaler TA, Wickham JN, Sannes KA, Wu KJ, Becker CH
Abstract Share this page
Abstract The effect of impurities on the analysis of single-stranded DNA oligomers by the technique of matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry has been studied using the matrix 3-hydroxypicolinic acid and 355-nm pulsed light. By mixing the DNA oligomers with different concentrations of impurities and recording mass spectra, limits are set on the tolerable level of a given impurity in a sample. The tolerance limits for sodium chloride, potassium chloride, sodium acetate, sodium fluoride, sodium dodecyl sulfate (SDS), and manganese(II) chloride were found to be approximately 10(-2) M. It was found that magnesium salts degraded the mass spectrum at much lower levels of 10(-4) M. The organic compounds tris(hydroxymethyl)aminomethane (Tris), urea, dithiothreitol (DTT), glycerol, and ethylenediaminetetraacetic acid (EDTA), when present as its ammonium salt, were tolerable at concentrations into the range of 0.25-0.5 M, while the organic polyamine compound spermine substantially degraded the mass spectrum at concentrations above 10(-2) M. When comparing these results for DNA analysis with previously reported limits for protein analysis, large differences are seen for some of the impurities tested.
This article was published in Anal Chem
and referenced in