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- Posts: 2
- Joined: Thu Sep 15, 2022 3:06 pm
I've been having issues with inconsistent signal response on my GC MS/MS. I'm looking at a set of 23 terpenes where I am injecting a five point curve ranging from 0.25 ppm to 6.25 ppm via headspace. When running the curve, the response on some of the heavier terpenes is varied and not at all linear. in fact, I get better signal responses for some of the lower concentrations for these heavy terpenes than I do with the higher concentrations. I'm sort of at a loss on what's causing this inconsistency and was hoping someone had some experience or pointers to help me puzzle this out.
My method is being run on a Thermo Fischer Trace 1310 Gc with a TSQ 9000 MS and a Triplus RSH autosampler. My inlet temperature is 225C with a 40:1 split. The column flow starts at 0.8mL/min but then ramps up to 1.5mL/min at a rate of 0.3mL/min after 10 mins. My oven program goes from 75C to 140C at a rate of 20C/min. 140C is held for 9 mins and then it ramps up to 280C at a rate of 22C/min and that is held for 1 min. My ion source is a EI source and its temp is 300. The Ms transfer line temp is 280C.