LC-MS/MS matrix effect ion enhancement.

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

2 posts Page 1 of 1
I validated analysis method using LC-MS/MS. Now I am evaluating matrix effect of analytes.
The method is this
1. 99 uL of beagle plasma + 1 uL working solution (in ACN) + 200uL MEOH
2. 14,000rpm 20 min centrifuge
3. 5uL injection to LC-MS/MS

However in my case matrix effect value using Matuszewski method is over than 150%. I use ACN, MEOH, DW as neat solution.
And then I tested 50mM potassium phosphate buffer instead of plasma 99 uL. In this result, peak height is similar as plasma result. So I think phosphate will enhance my analytes' ion response.
In my case what can I do for removing ion enhancement.
Same phenomenon is observed at addition of ethyl acetate 1mL to upper method and evaporation under nitrogen gas and reconstituted with meoh : dw (1:1) solution.

I can't find this case in other studies.

Let me know what can I do please....
There are plenty of things you can try to lower matrix effects. The question is, what are you allowed to change to a method that is already validated?

I do not think that phosphate will cause a matrix effect on your analyte. For this to happen, it has to elute at the same retention time of the analyte - which is very unlikely. But we don't know any details about the LC run and analyte itself.

There is a lot of literature on LC-MS matrix effects in serum samples that are prepared by a protein-precipitation protocol.
2 posts Page 1 of 1

Who is online

In total there is 1 user online :: 0 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: No registered users and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry