Chromatography Forum

Hello, I was wondering if anyone else has ever seen an orange/brown oily substance coming from the exhaust tube out of a CAD? It is a thick substance and is only seen on the outlet, the inlet tube is clear with no trace of the contaminant. We checked the purity of the N2 source and it is 99.9%, does anyone have any other theories what this could be?

Hi, Chromacolor,

I have no idea, but we have the same issue with one of our two CA detectors (both Thermo Fisher Corona Veo). Ours isn't brown, it's more yellow-orange, very clear, and thick. We put in a request for help with Thermo but haven't heard anything back aside from an acknowledgement that they were investigating. If you learn anything, I'd love to know what it is.

Best,

Robert

Hi, Chromacolor,

I have no idea, but we have the same issue with one of our two CA detectors (both Thermo Fisher Corona Veo). Ours isn't brown, it's more yellow-orange, very clear, and thick. We put in a request for help with Thermo but haven't heard anything back aside from an acknowledgement that they were investigating. If you learn anything, I'd love to know what it is.

Best,

Robert

Hi Robert,

What type of analysis do you run on the CAD detectors? DO you happen to run lipids?

Hi, Chromacolor,

I have no idea, but we have the same issue with one of our two CA detectors (both Thermo Fisher Corona Veo). Ours isn't brown, it's more yellow-orange, very clear, and thick. We put in a request for help with Thermo but haven't heard anything back aside from an acknowledgement that they were investigating. If you learn anything, I'd love to know what it is.

Best,

Robert

Hi Robert,

What type of analysis do you run on the CAD detectors? DO you happen to run lipids?

Also, what types of MP do you typically run with? Do you happen to know what year the CAD was purchased? I am trying to determine a common cause that may help us identify the cause.

Most likely this comes from your air supply line. If you don't have filtering system or traps, this might be coming from your compressor.

Are you running lipids with THF or ipa as your mobile phase?

Hi, Chromacolor,

I have no idea, but we have the same issue with one of our two CA detectors (both Thermo Fisher Corona Veo). Ours isn't brown, it's more yellow-orange, very clear, and thick. We put in a request for help with Thermo but haven't heard anything back aside from an acknowledgement that they were investigating. If you learn anything, I'd love to know what it is.

Best,

Robert

Hi Robert,

What type of analysis do you run on the CAD detectors? DO you happen to run lipids?

Also, what types of MP do you typically run with? Do you happen to know what year the CAD was purchased? I am trying to determine a common cause that may help us identify the cause.

Hi, Chromacolor,

I apologize for the late reply. We use the Corona Veo CAD for running low M.W. PEG derivatives. Our mobile phases are typically acetonitrile and water with 0.1 vol% in each. Our nitrogen is supplied either by a nitrogen generator from Peak Scientific or a nitrogen cylinder (grade 4.8 or higher) from Praxair.

Best,

Robert

Are you running lipids with THF or ipa as your mobile phase?

We were running with different MPs including a combo of IPA, ACN, MeOH, and water containing TEA, TFA, and FA in different combos.

Are you running lipids with THF or ipa as your mobile phase?

Yes

Are you running lipids with THF or ipa as your mobile phase?

Yes