Signal strength, trichloro vs tribromo phenol.
Posted: Tue Nov 29, 2011 4:49 am
I am seeing something I'd like a reason for.
I am having some trouble with the sensitivity for trichlorophenol.
I infuse a solution containing tribromophenol and trichlorophenol at 1 ug/ml in methol/10mM AmAc (75%/25%).
MS scan mode. from say 150 to 350 AMU.
Regardless of the parameters I use (orafice voltage), the signal for the bromo is about 3 times larger than the signal for the chloro, (even considering the isotopic ratio of bromine is 50/50 79 and 81 whereas chlorine is 75/25 35 and 37). The largest peak for the trichloro is at 194.9 and those for the tribromo are at 328.8 (and 330.8 and of equal intensity).
I tried adding a very dilute Ammonia solution to the infusion solution (final <0.2%) but the signal remains about the same.
Should I not expect a similar (if not greater, based on electronegativity) ionization of a trichlorophenol as compared to a tribromophenol?????
Alp
I am having some trouble with the sensitivity for trichlorophenol.
I infuse a solution containing tribromophenol and trichlorophenol at 1 ug/ml in methol/10mM AmAc (75%/25%).
MS scan mode. from say 150 to 350 AMU.
Regardless of the parameters I use (orafice voltage), the signal for the bromo is about 3 times larger than the signal for the chloro, (even considering the isotopic ratio of bromine is 50/50 79 and 81 whereas chlorine is 75/25 35 and 37). The largest peak for the trichloro is at 194.9 and those for the tribromo are at 328.8 (and 330.8 and of equal intensity).
I tried adding a very dilute Ammonia solution to the infusion solution (final <0.2%) but the signal remains about the same.
Should I not expect a similar (if not greater, based on electronegativity) ionization of a trichlorophenol as compared to a tribromophenol?????
Alp