Unfortunately you have come across one of those problems for which a collision cell is the best choice. The problem with the interference on Cr53 from 37Cl16O is that the correction mass would be 51 (the other Cl isotope) and that is unfortunately also the mass for V which is essentially monoisotopic, and therefore not correctable. If you were absolutely positive that there was never any V in your samples, the correction would be simple and would be just the Cl isotope ratio. However, that isn't likely to ever be the case.
BTW, it is always a good idea to measure the Cl isotope ratios in a clean HCl blank and use the measured factor rather than the theoretical 3.127 value. In practice other effects including background levels and mass bias make the measured factor slightly different (usually a bit smaller) from the theoretical value.
Steve Wilbur | Senior Applications Chemist, ICP-MS Systems | Agilent Technologies, Chemical Analysis Solutions Unit |
1615 75th Street SW, Suite 210, Everett, WA 98203-6261 | (t:425.356.6333 | : 360-468-3683 | :: [log in to unmask]
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Randy Mercurio
Sent: Friday, December 17, 2010 9:14 AM
To: [log in to unmask]
Subject: Cr 53 Interference Equation
I've searched the archives and can't seem to find any discussion on the following topic: I'm looking to analyze V 51 as accurately as possible with a correction equation and because the equation used for correction, I believe it is -3.127 * (Cr 53 - (0.1134 * Cr 52)), is linked to Cr 53 I was seeking some help in the proper equation to use for Cr 53. Can anyone share an effective correction equation to use for Cr 53? If it is of any help I am analyzing solutions with a standard 3.35% HCl and does go higher in my ICSA and AB solutions. I've attempted to correct the 37Cl16O for Cr 53 using the count rate in the calibration blank but because of the increased Cl in the ICSA it is not effective. Is there a way around this?
Randy J. Mercurio
Eastern Research Group
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