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Questions related to Liquid Chromatography
Is the chromatographic peak a valid measure of a compounds` (relative) abundance in LC-MS data? We have recorded three MS/MS spectra; their retention time falls into a specific chromatographic...
14 January 2021 7,073 6 View
Hi RG reserchers, recently our lab purchased a liquid chromatography coupled with mass spectrum brand “LC/MS-2020 shimadzu, Nexera XR/ LC 20AD”. When we operated it using phenolic extracts, we...
09 November 2020 7,808 5 View
I have three dataset of quantitative and qualitative liquid chromatography, GC-MS and DNA barcoding of few samples. What would be the best way to discriminate and visualize the data?
26 October 2020 1,453 9 View
Does anyone have any tips on clearing blocked nanoViper (20 uM ID) tubing in a Dionex 3000 for LC-MS/MS? We're having recurring high pressure errors in our loading pump, and we've isolated it to a...
29 July 2020 3,933 3 View
For a while, I have been experimenting with improving the linearity of my method. I have noticed that increasing my deuterium labeled (3x) internal standard to a concentration 2.5 times the ULOQ...
23 March 2020 3,188 7 View
Can anyone help me with peer reviewed papers that explain whether or not ions are formed in the ESI source? Is this what they call 'right-way-round' principle? Then how come that some for some...
11 March 2020 2,797 1 View
Can 2D-LC system be built by connecting two orthogonal columns with the use of two pumps and a switching valve? I want to build a tandem system myself. Is this practical?
18 February 2020 5,313 3 View
Hi everyone, I am looking for the manual of the Spot Liquid Chromatography Flash from Armen Instrument: we have one of them in our laboratory but it did not run for a while. I never used it...
02 February 2020 5,807 3 View
02 February 2020 5,323 3 View
Dry Column Vacuum Chromatography (DCVC) and Vacuum Liquid Chromatography (VLC) are same OR diffrent techniques?
10 January 2020 9,750 2 View
01 January 2020 7,290 2 View
I have read in some papers that nano liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is more sensitive than conventional LC-MS/MS. But they never really mentioned why. I'm...
01 January 2020 7,764 6 View
I'm been running Agilent OPA amino acids method but recently my column loss resolution for some of the peaks and will not resolved to baseline. After some discussion with others people in the...
10 October 2019 6,090 4 View
When using the LC-MS/MS system to dertermine CPs compounds, I observed a problem that when the standard is prepared in Methanol:Water 1:1 solution, the system gives no result of analyte. However,...
22 August 2019 6,654 4 View
I am struggling with Peak purity analysis, if anyone can help with that please. I am working on Dionex-Ultimate 3000 uHPLC.
03 March 2019 8,829 14 View
Hi I' m really stuck on this so any help is appreciated. I am doing a project on cinchona alkaloids. I made 4 calibration curves, one for each alkaloid standard, and used hplc data and the...
02 February 2019 9,888 7 View
We've recently started using a single quad LC/MS system (Shimadzu LC/MS-2020, for what it's worth) for mouse plasma AA analysis (the 20 common EAA and NEAA). Pre-column derivatization seems to be...
02 January 2019 1,683 5 View
01 January 2019 2,694 5 View
The data that I have are of lcd format from liquid chromatography. Anybody knows how can be converted into matlab format? Any function for that? Thank you!
11 November 2018 1,468 4 View
I've observed that my procedure of mobile phase preparation affects the reproducibility of results. I used volumetric flasks, cylinders (for addition of second solvent) that is not so comfortable...
10 October 2018 8,283 15 View
My lab is new to metabolomics analysis and for the past few months, we have been searching for a protocol to prepare our human fecal samples for LC-MS analysis, done by a metabolomics lab on...
02 October 2018 6,590 8 View
Dear all, recently I was confronted with the statement that "rare sugars" can be used to identify food fraud or the use of enzymatic food treatment. Initially, I was surprised to learn, that...
18 September 2018 9,499 5 View
09 September 2018 6,099 6 View
Hello Dear researchers I read about aminoacid analysis in hydrolyzed protein by Liquid Chromatography. Previous derivatization is required and a subsequent hydrolysis too. It is mentioned in the...
06 June 2018 4,613 6 View