Persistant Peak "Blob" upon injection

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

3 posts Page 1 of 1
Hi, I have been doing optimizing a new HPLC method on a new "aqueous" column and ran into some older issues that I had on a spherisORB ODS2 C18 column. There is a persistent blob that always comes off the column.

At around 4 min past the solvent front we begin to see the weird blob. Here are some things I have tried to fix the problem.

HPLC- columbic cell detector

- replace the mobile and flush column
- clean and replace rheodyne parts
- replace sample loop
- try different percentages of MeOH (does seem to move blob slightly)
- injecting pure MeOH makes the blob really big

When I just do the trigger I don't see the blob, however, if I inject mobile phase into the loop I see the blob. If I inject water I see the blob or if I inject the sample I also see the blob.
It might be just me, but I have some troubles understanding your terminology. What is a columbic cell detector? Does 'doing the trigger' means a run without injection?

Which mobile phases are you using? Is this a gradient method? What column are you using?

I can sort of imagine what a blob looks like but a chromatogram would help!
Have you tried the same method and injections with a different column? Both a different identical column and perhaps a non-identical column?
3 posts Page 1 of 1

Who is online

In total there are 14 users online :: 0 registered, 0 hidden and 14 guests (based on users active over the past 5 minutes)
Most users ever online was 599 on Tue Sep 18, 2018 9:27 am

Users browsing this forum: No registered users and 14 guests

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry