In this article, we consider whether it is ok to back-flush a column. If a C18 column is used for a routine analysis and the pressure has risen, as in this example, if the column is reversed and unplugged will this be ok or will be the column be damaged?
JWD : The short answer is that most silica-based HPLC columns can be reversed without damage. There are several things to consider, and you should always check with the column care and use instructions to be sure that column reversal is OK for your column. First of all, you are quite right that reversal of the column may be effective in cleaning off whatever is plugging up the column. The assumption is that particulate matter from your sample, mobile phase, or worn pump or injector seals has blocked the inlet frit of the column. This is normal over time. If this is the case, column reversal will displace this material perhaps a third of the time, causing the pressure to go back to normal. If you want to reverse-flush, just reconfigure the column. Simply reverse the column and flush to waste. Disconnect the detector, because you don’t want to flush any particles into the detector cell.
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