LC-MS/MS tends to be used for what kind of molecules?
Larger ones like proteins
What are two advantages of tandem mass spec?
1. You can use a soft ionization followed by harder ionization to get molecular plus fragment information
2. You can use the first MS to clean up matrix interference
Chemical suppression is used for what technique? What does it do?
It reduces background conductivity of the eluant and so increases sensitivity
What are 6 detection methods used for IC?
Photo diode array
Both ICP-MS and LC-MS contain ___ and ___ cones at the interface to the MS
Flow rates for electro spray ionization are typically (small/large)?
Extremely Small, < 1 uL/min
Is ESI a soft or hard technique?
Which technique gives smaller HETP values? HPLC/UPLC
UPLC (therefore it has higher resolution)
Which has higher pressure? HPLC/UPLC
UPLC (max around 15,000 psi)
Which has shorter run times? HPLC/UPLC
If you don't have an MS detector for you IC and it's hard to see a peak, what could you do?
Put other detectors back to back - maybe one of them will see the peak
: DAD --> RI
Is refractive index a good detector for gradient elution?
No! You must use isocratic elution for an RI detector
UPLC uses ___ eluant than HPLC
This can reduce costs and is environmentally friendly
Disadvantage of UPLC
Created by Cynthia Skinner