Tijana Vasiljevic

9 Questions 16 Answers 0 Followers

Questions related from Tijana Vasiljevic

LC/MS and GC/FID give different answers on fatty acid amounts for the same sample?

Hi everyone! I am testing free fatty acid in coconut oil and coconut oil treated with microbial cells. For the GC/FID I am using a methylation (methanolic HCl at 90 degrees celsius) approach to...

16 August 2023 5,728 8 View

Dilute and shoot for free fatty acid analysis?

Hi everyone, I am looking to develop a method for analysis of free fatty acids in oil (coconut, canola, olive... etc.). I've noticed that there are some methods out there that simply use...

05 June 2023 2,260 1 View

Can hyaluronidase completely breakdown hyaluronic acid of lower molecular weight?

Hi all, I am using hyaluronidase from sheep testes for breakdown of hyaluronic acid and analysing by HPLC. Is it possible for hyaluronidase to perform more "destruction" to hyaluronic acid of...

05 April 2023 1,550 0 View

Surfactant carryover in LC/MS?

Hi everyone, I am trying to develop a LC/MS method for the analysis of 2 anionic surfactants. While the method seems to be working fine, I am facing an odd carryover issue. - We are using a...

14 December 2022 4,392 11 View

Injections of QC standard yield increasing areas in negative ionization mode (LC/MS/MS)?

Hi all! I am using a Waters-TQS micro (LC/MS/MS) in negative ionization mode (MRM) to analyse a few compounds. When doing QC injections (i.e., repeated injections from same vial of standards at a...

01 December 2022 8,218 4 View

How do you calculate void volume time for a GC column?

Hi guys, How would you calculate void volume time for a GC column? I know that you can calculate void volume for HPLC columns using a formula. What is the approach for a GC column? Looking at the...

01 November 2022 6,896 3 View

Area of derivatized analyte greater than its pure standard?

Hi everyone! I am doing a derivatization reaction for conversion of formaldehye into a more friendly GC analyte, diethoxymethane. The reaction is done in a 10 mL headspace vial, and a sample of...

20 October 2022 932 6 View

How do you determine derivatization yield for a gas chromatography reaction?

Hi everyone, Can somebody explain how I can determine the derivatization yield of analyte? I've seen lots of papers that detail their yields, but none of them mention how they calculated the...

01 January 1970 6,101 1 View

How can you quantify peptides using LC/MS?

Hi everyone! I am asking for a friend - but could someone recommend some useful (focus on practical) literature for quantification of peptides using LC/MS? Any practical tips to share? Thank...

01 January 1970 176 8 View