LC/MS/MS Parameter Seeting

waters2695,Agilent Extend C18,waters2420ELSD?

(1) ELSD?
(2) & (3) : 225 nm.

For Traditional Chinese Herbs only: -> Chromatogram Peaks and Retention Time(Chromatographic Activity) -> Chromatographic finger identification...

Biosample Assay by LC-MS (2)

(1) Capillary Voltage: -3.0 kv.
(2) Cone Voltage: -40 v.
(3) Collision Energy: 18 ev.
(4) MRM: m/z 299.5 →m/z 255.2.

Biosample Assay by LC-MS (1)

Happy Spring Festivals 2009!

Ionization Suppression Summary

(1) Compounds That Cause Sensitivity Suppression.
-Salts can interfere with ionization and can cluster to complicate spectrum (but also aid in identification).
-Strong bases or quaternary amines can interfere with positive mode analytes, e.g. Triethylamine(TFA).
-Acid -Sulfuric/Sulfonicacids and TFA interfere in negative mode.
-Phosphate buffer and non-volatile ion pairing agents (e.g. SDS) can cause severe suppression and complex spectrum.

(2) Dimerization([2M+H]+) can occur at high concentration, leading to non-linearity during quantitation.
-DimerSignal at m/z = (MW*2) + 1.
-Can cause non-linearity at high concentrations.

Five Ways to Reduce Acetonitrile Consumption

The current global shortage of Acetonitrile has pushed us to find 5 ways to reduce thedependence on Acetonitrile

Option 1: Reduce column ID:

Reducing the HPLC column ID from 4.6 mm to 3.0 mm can result in > 50 % reduction in mobile phase consumption.

Option 2: Reduce particle size and column dimensions:

* Reduces solvent consumption
* Maintains resolution
* Reduces run time

Option 3: Reduce column length:

Option 4: Substitute Acetonitrile with Methanol:

http://www.phenomenex.com/images/methanal_replacement.gif

Option 5: Solvent recycling (Isocratic separations only)

Reference by Phenomenex.

VIP reference for the Method Transfer....

It's time to clean the Inlet....

Agilent 6890N ECD.
Temp Ramp: 80℃（1min)----20℃/min--- 260℃（15min)----5℃/min---300℃（3min),
Detector Temp: 300℃
Inlet: 250℃
GC Column:HP-5.

Baseline drift?

Maybe the collision energy (CE) is too LOW

(1) Maybe the collision energy is too LOW. The First MS is not full a fragment.
(2) Are you using ESI mode?
(3) If the Molecular weight is 237, for SIM -> Here are three characteristic ions (m/z) 164，149，122 I highly recommend them.
(4) MS-MS (MRM): Need to search online for the product ion and parent ions.
(5) If only need the full scan, why not adjust the concentration of analyte.

Hope it helps.