A Comparative Study of the Phosphotriester Versus the Phosphoramidite Approach to Nitroxide Labeled Oligo dT

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• We determined that the nitroxide undergoes a 10 to 20% destruction during each oxidation step with 0.1M I2 in H2O/2,6-lutidine/THF. 13 While the phosphoramidite protocol for the Applied Biosystems 380A or 380B instrument requires 0.1M I2, the Pharmacia protocol calls for only 0.01M I2. EPR experiments with this tenfold lower I2 concentration showed a considerably smaller nitroxide destruction
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