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- Posts: 34
- Joined: Thu Oct 08, 2015 9:25 am
- Location: Pretoria, SA
I have been trying to calibrate a method for analysing Volatile Petroleum Hydrocarbons using headspace(Single Ion Monitoring) on a Bruker Scion SQ GC-MS, with an Rxi-5Sil MS column. The standard I am using is a Restek one, WA VPH Standard(1 000 ug/mL). The standard has 15 components in it and the problem I am having is that the regression is bad(as each component has its own linear curve), for the BTEX components in the standard the regression is closer to 1 but still off by about 8-20%. Then the rest of the components like the aliphatics have a coefficient of determination that is way below, like 0.079 which then either over-recovers the actual prepared concentration or under-recovers.
Has anyone ever worked with this standard or had a similar problem? How unstable can these standards be?
Kind regards
Gugu