Corona CAD question
Posted: Tue Jul 21, 2009 10:36 pm
hi,
I am currently running an LC-CAD method. The CAD i am running on is a first generation Corona . I have read a great deal of literature about this instrument and the maufacturer claims that the CAD is sensitive down to just a few ng/mL. I am currently running a method with n-ethylmethanesulfonate and I am seeing great peak shape at all concentrations of 50mcg/mL and greater. Anything less than 50, my peak shape completely disappears. My eluent is 95:5 CH3CN:0.1% NH4COOH (aq) isocratic, this is also my sample diluent. My CAD parameters are a range of 1-2 pA and my filter is on High. I have tried increasing my organic concentration up to 99% organic to no avail. Also, I am using a "aqueous normal phase" Diamond Hydride column. Has anyone had this sensitivity issue while using a CAD? how was it resolved? Thanks.
I am currently running an LC-CAD method. The CAD i am running on is a first generation Corona . I have read a great deal of literature about this instrument and the maufacturer claims that the CAD is sensitive down to just a few ng/mL. I am currently running a method with n-ethylmethanesulfonate and I am seeing great peak shape at all concentrations of 50mcg/mL and greater. Anything less than 50, my peak shape completely disappears. My eluent is 95:5 CH3CN:0.1% NH4COOH (aq) isocratic, this is also my sample diluent. My CAD parameters are a range of 1-2 pA and my filter is on High. I have tried increasing my organic concentration up to 99% organic to no avail. Also, I am using a "aqueous normal phase" Diamond Hydride column. Has anyone had this sensitivity issue while using a CAD? how was it resolved? Thanks.