By Brian Werner on Wednesday, September 24, 2003 - 07:58 am:
I do analysis for PAH's on environmental samples. I use a Phenomenex Hypersil Green PAH column for the analyis and a HP 1100 HPLC. I routinely have trouble with the compound Benzo(a)pyrene drifting outside our laboratory control limits. It goes out of control both high and low. All other PAH compounds are not a problem. There is not a consistent cause for this that I have seen (i.e.- sample carryover,etc.). I have seen this even after running clean standard samples. I have had some suggestions from fellow HPLC analysts from within the company I work for to backflush column. I have tried this with no luck. Does anyone have any other suggestions of what could cause this or procedures to correct this problem.
By Anonymous on Friday, September 26, 2003 - 06:31 am:
Hello, Brian
look at our question in "Archives July 02 - Dec 02: HPLC problem with PAH's analysis after use of triethylamine buffer".
We have experienced pratically the same problem (our chromatograph is HP 1090); the only solution that we have found is flushing the system a lot with acetonitrile-water and performing repeated injections of standard solution until the initial response is restored.
We suspect that problem may arise from acetonitrile contamination but we have not found a complete explanation to this behavior
Best regards.