S14-0011, 1/2 Shipping Release

Record: 855

Category: Applications
Product: NH2P equilibration
Sample:

Question
Sorry for not responding to your e-mail earlier this week.
I had to purchase perchloric acid for column regeneration. I am expecting to receive it today. As for my samples, I am dissolving them in water, then using a 75/25 ratio of acetonitrile/water to make a working solution. I did try injecting them in 100% water too, when the previous mixture did not work. Increasing acetonitrile to 85% did not change the retention time. Moreover, even mannitol is giving the same retention time as sucrose. When I start regenerating the column (page 20), is # 6 means acetonitrile/water mixture? The flow rate suggested (2 ml/min) steps 1 to 5 and 1 ml/min step 6 are above the limit of the column, which is 0.4 ml/min, is there a problem there? Please contact your Japanese collaborators, and ask them about the best way, if any, to make this column work better.

Answer
Please use the flow rates recommended for your specific column (0.4 mL/min) and use the respective eluents in the order listed: water, 0.1 M HClO4, water 0.1 M NaOH, water, eluent for analysis. For step 6 use the eluent you are going to use for analysis.

I think that the equilibration solution of 100 mM ammonium acetate has protonated all of your active retention sites so your target compounds have no ability to “stick” to the column. Please clean the column and reject the sucrose under the CoA conditions. I would like to know the results of your analysis.

 
 
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