Cyano column producing PEGs??
Posted: Fri Jun 24, 2011 4:27 pm
Hi everyone,
I feel slightly stupid even writing this, but I'm troubleshooting a brand new silica-bonded cyano column that appears to be bleeding PEGs (polyethylene glycol, molecular ions from ~500 to ~900 44 Da apart). I've swapped out the column for an old (good) one, run blanks, run no-column installed blanks, tested everything else I can think of, and so it appears to be that the column is producing a lovely chromatogram of PEG peaks which get larger if the column has been sitting and diminish as the column runs through a sequence ...
anyone seen this from an hplc column before?
my only theory is that the packing was contaminated or the column hardware was dirty.... we see these PEGs often in samples from plastic or soap-heavy origins, but never apparently originating from a column!
background: we've been running a normal phase method on diol columns for ~ 10 years, we're moving to a cyano phase (long story) using the same eluents: A = 20% IPA in hexane with 0.1% formic acid and ~0.01% NH4OH, B = 10% water in IPA with the same additives, gradient is 100% A to 50% B.
thanks for any comments,
Helen
I feel slightly stupid even writing this, but I'm troubleshooting a brand new silica-bonded cyano column that appears to be bleeding PEGs (polyethylene glycol, molecular ions from ~500 to ~900 44 Da apart). I've swapped out the column for an old (good) one, run blanks, run no-column installed blanks, tested everything else I can think of, and so it appears to be that the column is producing a lovely chromatogram of PEG peaks which get larger if the column has been sitting and diminish as the column runs through a sequence ...
anyone seen this from an hplc column before?
my only theory is that the packing was contaminated or the column hardware was dirty.... we see these PEGs often in samples from plastic or soap-heavy origins, but never apparently originating from a column!
background: we've been running a normal phase method on diol columns for ~ 10 years, we're moving to a cyano phase (long story) using the same eluents: A = 20% IPA in hexane with 0.1% formic acid and ~0.01% NH4OH, B = 10% water in IPA with the same additives, gradient is 100% A to 50% B.
thanks for any comments,
Helen