Asal Asali

6 Questions 8 Answers 0 Followers

Questions related from Asal Asali

How to identify possible metabolite from chromatogram?

We have done the analysis for a pre-clinical study and we have observed additional peaks in the chromatograms. We think that these peaks are metabolites. The concentration of the additional peaks...

03 December 2020 6,250 10 View

Why does increasing the internal standard concentration (higher than the ULOQ) improves linearity in LC-MS/MS?

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 3,015 7 View

Where are protons in ESI+ formed in LC-MS/MS?

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 2,611 1 View

How to distinguish ion-source saturation and detector saturation with LC-MS/MS?

I am trying to develop a LC-MS/MS method for a compound. The calibration curve flattens at the higher concentration points when measuring in the range of 2.5-5000 ng/mL. It is lineair when...

05 June 2019 3,050 7 View

Why is a linear calibration curve preferred?

For bio-analysis with LC-MS/MS, a linear calibration curve is preferred over a quadratic. Why is this? Is it OK to continue method development with a quadratic fit? I have to add that the...

04 March 2019 5,645 13 View

How to further improve LC-MS/analytical chemistry skills

I finished my masters in analytical chemistry, but there is so much more to learn. My main interest is the hard core fundamentals of chromatography and mass spectrometry. What positions in the...

01 January 1970 9,054 8 View