Dear all,

Does anyone has experience in cleaning the CI ion source of Agilent 5973 MSD? I find that after cleaning it under a normal procedure (with scrubbing with aluminum powder, sonication with methanol etc), the ion source gets dirty very easily after several runs of clean samples(due to rapid ramp of EM voltage). The material of CI ion source looks different from the EI counterpart. Does it need special cleaning? Please advise.

CI is an inherently "dirty" technique. You are reacting hydrocarbon radicals in the ion volume to form heavier hydrocarbons, which may be depositing and causing problems. The Agilent repeller in my experience is more sensitive to low levels of contamintation than some other systems. When I clean a source I usually use a rotary (Dremel) tool with the aluminum oxide powder slurry, as I find I can clean more quickly and efficiently than doing it manually. When cleaning manually try spending more time cleaning the repeller to make sure all deposits are gone. I have had repellers look clean, but improve dramatically in performance after cleaning.