Deionization of formamide with Biorad AG501-X(D).
We have studied different conditions of the deionization of formamide with Biorad mixed bed resin AG501-X(D) and find that contrary to the popular usage, drying the resin before deionization produces the best results. In a typical deionization procedure, conductivity initially goes down, reaches a minimum plateau and finally goes up again. The initial rate of deionization, the minimum conductivity reached at the plateau and the rate of final rise in conductivity depend on whether the resin is dry or wet (i.e., straight from the bottle) and on the amount of resin used. In general, wet resin produced faster initial deionization, higher minimum conductivity and quicker final rise in conductivity. Surprisingly, a smaller amount (5%) of resin worked better than a larger amount (20%). With smaller amount of resin, although initial deionization was slower, the minimum conductivity achieved was lower and the final rise in conductivity was slower. This was partly due to the fact that the conductivity of formamide increases faster with increasing amount of water in it.
Eugene Tech International, Inc., Allendale, NJ 07401.
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Samanta
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Engel
D002852:Chromatography, Ion Exchange / Q000379:methods; D004553:Electric Conductivity; D005559:Formamides / Q000302:isolation & purification*; D007475:Ion Exchange Resins; D013997:Time Factors
D005559:Formamides; D007475:Ion Exchange Resins; C031066:formamide