Enriqueta casal-banciella

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Questions related from Enriqueta casal-banciella

How could I work with Melatonin in plasma?

Hi, I would really appreciate if somebody with experience on working with Melatonin could help me. I would like to analyse melatonin in plasma. I need to detect low concentrations. I have read...

03 August 2023 1,094 0 View

How to quantify 4beta-hydroxycholesterol in plasma by LC MS when BSA gels ?

Hi, I am trying to determine 4beta-hydroxycholesterol in plasma. It is endogenous, for this reason I need to use a surrogate matrix (1% BSA) but I have problems with this protein. 1. In the first...

05 May 2023 307 4 View

How to increase the sensitive of ergopeptide alkaloids in LC/MS?

Hi, I would like to analyse 8-dihydroxy ergotamine in plasma by LC/MS. I need to increase the LLOQ and for this reason I need to derivatize the molecule. Does anybody have experience with these...

21 June 2022 3,370 1 View

Is there any free software program to predict the highest peptide and fragment it?

Hello, I would like to analyse a peptide by LC-MS/MS. I am not experience in peptides. I would really appreciate if somebody could help me. 1. I have the sequence of the peptide and I would like...

14 November 2021 7,929 2 View

Could I use ethylene glycol as additive (up to 50%) with Immobilized Metal Affinity Chromatography?

Hi, I have expressed a protein in mammalian cells. It is a HIstidine tagged protein. I have tried to purifiy this using a buffer with imidazol in IMAC. This protein is very hydrophobic and...

09 August 2021 7,170 4 View

How do zwitterionic buffers work on the stability of meropenem in plasma?

Dear all, I need to develop a method (by LCMS/MS) to analyse meropenem in plasma I do not have any experience with this compound and I was wondering if you could help me. I would need to stabilty...

24 July 2021 6,459 0 View

Where can I get information about acidifying and adding stabiliziers of whole blood and plasma?

Hi verybody, I would like to get information about to carry out the acidification of my sample (whole blood and plasma): the requerided volume to stabilize my sample without modify the matrix,...

31 March 2021 6,042 2 View

Why the protein is not secreted to the medium?

Dear all, Why is a protein, which is expressed in HEK293 cells, not excreted to the medium? The protein remains soluble into the cell. Which could be the reasons? Thanks for your time! Best...

05 November 2020 4,581 8 View

Why Incurred Sample Reanalysis (ISR) for N-desmethyl sildenafil fails?

Dear all, I would like to develop a method (UPLC-MS/MS) for the determination of sildenafil (viagra) and its metabolite N-desmethyl sildenafil in plasma using protein precipitation as extraction...

25 October 2020 4,097 9 View

Problem with the expression of recombinant proteins (in HEK cell)

Hello everybody, I am trying to express several recombinant proteins in HEK cell line by transient gene expression. I am using as medium FreeStyle 293F to produce the proteins by...

01 January 1970 6,468 5 View