Describe the problem
Tell me the symptom, not the part number
You do not need to know what to buy. Describe what the instrument is doing and what you are trying to separate, and I will tell you where I would look first. If a part is the answer, I will quote it. If it is not, you will get that answer instead and it will not cost you anything.
Rather not use a form?
Email, call, or send a WhatsApp message. Same answer either way, and a photo of the chromatogram is welcome on any of them.