Thursday, February 19, 2009
Sunday, February 15, 2009
waters2695,Agilent Extend C18,waters2420ELSD?
Thursday, January 22, 2009
Monday, January 19, 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.
-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.
Thursday, January 8, 2009
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.
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.
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