Showing posts with label Solvent. Show all posts
Showing posts with label Solvent. Show all posts
Saturday, February 1, 2020

Air Bubbles Exiting the HPLC PUMP, Reasons Why.

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Reasons For Air Bubbles Exiting The HPLC Pump: Pump Cavitation: When the pump pressure fluctuates wildly up and down, at very low pressu...
Saturday, April 8, 2017

LC-MS Contamination? Another Possible Cause. Are your Mobile Phase Bottles and Pick up Filters Clean ?

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One of the mo re common LC/MS problems I am asked to help solve deals with contaminate d LC-MS or LC/MS/MS systems. Over time, m any syst...
Saturday, September 24, 2016

HPLC Peak Splitting. Common Reasons For It

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True "Split" HPLC peaks, not resulting from co-elution of an other peak, can be caused by a number of chromatography probl...
3 comments:
Saturday, August 1, 2015

An Often Ignored HPLC & LC/MS Contamination Source. Did you check your Vacuum Degasser?

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The introduction of electronic vacuum degassing / degasser modules to the liquid chromatography industry a few decades ago has introduced se...
2 comments:
Saturday, May 10, 2014

Gradient Mixing Test For Your HPLC Pump (Step Gradient)

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The most popular type of gradient pumping module used to perform HPLC analysis utilizes a low pressure mixing valve in their design. These v...
Saturday, May 18, 2013

HPLC Solution Degassing, Sparging With the Wrong Gas (Gas Choice Matters)

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The other day I took a call from a client whom explained they were having a number of problems with their HPLC pump. They felt that they w...
1 comment:
Tuesday, February 12, 2013

pH Measurement of HPLC Mobile Phase Solutions and Buffers

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Several times each month I am asked how to "correctly check and adjust the pH of an HPLC buffer solution which has an organic solvent c...
2 comments:
Monday, September 24, 2012

HPLC Mobile Phase Filtering & Solvent Inlet Filters

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HPLC Mobile Phase Filtering:  The tubing and valve passageways of the HPLC system are very narrow and clogs can result from using solu...
Tuesday, November 1, 2011

HPLC Solvent Properties Table (e.g. Polarity, Density, Boiling Point...)

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Here is a link to a table listing common chromatography solvents and their physical properties (e.g. viscosity, polarity, UV absorption...)....
Monday, October 17, 2011

HPLC PUMP SOLVENT COMPRESSIBILITY VALUES

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Have you ever noticed excessive pump ripple (baseline noise) that is not caused by a defective check valve ? The ripple might be due to an ...