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Questions related to Liquid Chromatography
To check whether a peak is not contaminated with other compound(s) is very important for proving the selectivity of a method. We can do it easily if we use DAD or MS detectors. Generally, for...
03 March 2015 2,015 5 View
I showed the change of enantiomer purity during vaporisation
03 March 2015 2,245 5 View
Mass spectrometry analysis give rise to redundancies, mostly, due to multiple identifications of the same gene product present in different bands or in the same band, or different strain of T....
02 February 2015 7,725 3 View
I am seeking cheap sources of LH-20 and I would like to know if I can recycle it, and how many times is this feasible? How much would I need to buy it to complete a few structure elucidation...
01 January 2015 5,319 5 View
Hello. Regarding the analysis of amino acids with HPLC the OPA reagent (ortho-Phthaldialdehyde) is suitable to make a pre-column derivatization of those in order to make them detectable with a...
01 January 2015 787 5 View
I would like to separate an ion-association complex which is not soluble in a aqueous phase.
31 December 2014 5,109 5 View
12 December 2014 2,506 5 View
I´ve been reading about peak tailing, loss of resolution and peak broadening in reversed phase columns and some authors explains that heavy metals can produce peak tailing on C18 columns. Any body...
12 December 2014 3,747 1 View
What will be the conditions i.e mobile phase, concentration of the standard L-ascorbic acid, concentration of the sample?
12 December 2014 4,557 1 View
How can I solve the problem of peak splitting for low concentration of a drug in DPV?
12 December 2014 6,464 2 View
Thanks in advance!
12 December 2014 9,471 2 View
I am very new to understanding UPLC, and need some help to get started. I would like to run analysis on some blood samples (I have serum and plasma) to detect concentrations of a number of...
20 November 2014 6,640 3 View
The list of masses appear without charge in my LC-MS chromatogram usig formic acid. I supose molecules did not ionize. What can I do?
13 November 2014 6,749 7 View
Peak shape and resolution was not good when I used acetonitrile on C18 column in method development of my compound. But using methanol as mobile phase gave good peak shape. What would be the reason?
12 November 2014 2,286 7 View
I tried different analytical reverse phase columns ,different mobile phases with different time programs , different needle wash solutions . But I could not solve the problem. Adding low...
12 November 2014 5,823 7 View
Hello, My team and I are working on a method to determine the concentration of TBT in seawater. We tried to directly inject the filtered sample in seawater using 2% Formic Acid in Water and 2%...
11 November 2014 6,039 5 View
11 November 2014 1,734 4 View
11 November 2014 9,143 8 View
I am trying to reproduce the chromatography described in this document and am consistently eluting my compound when switching back to the A solvent. I have purchased a second column and remade...
11 November 2014 3,457 1 View
11 November 2014 1,933 8 View
Hello, does anyone have any experience with packing columns for nano LC? Any suggestions on the tubings and the method used for column packing?
11 November 2014 4,125 3 View
11 November 2014 10,120 8 View
We have a huge contaminant at 100.0757 m/z that we think is methylpyrrolidone [M+H]+. We're using a gradient of MP A: H2O (0.1% Formic acid) and MP B: ACN (0.1%formic acid) on a C18...
11 November 2014 5,702 4 View
In AOAC 2009.01 and AOAC 2011.25, liquid chromatography-refractive index is used for measuring low molecular soluble dietary fiber. Can I use ion chromatography to measure low molecular soluble...
11 November 2014 5,092 5 View