Nice to meet you.
I'm doing ESI-MS analysis and read some papers about Na ion.
However, there is no description of Na.
Therefore, I want to ask where the Na is from.
Can you answer me?...
Thank you so much.
Hi,
Nice to meet you too!
Adduct ions that are observed in peptide and protein spectra generated by electrospray ionization (typically sodium, potassium, iron) can originate from a multitude of sources, including the water used for dilution, the glassware used to prepare solvents and samples, the reagents used to prepare buffers, so basically from anywhere.
Sometimes sodiated ions ([M+Na]+) can be helpful, for example if protonation of a compound is difficult, or when you're interested in the specifics of the fragmentation of sodiated (versus protonated) species, for example when analyzing sugars.
Hope this helps!
Traces of Na+ are ubiquitous and are often found in cationic adducts observed in MS.
Mostly GLASS containers. Sodium is very common.
Sodium ions are everywhere! One of the most common sources are the water, glass bottles and containers used for the liquids and solvents. Sodium adducts can be very useful during LC-MS method development. * Many professional chromatographers like myself take advantage of this fact and use them to improve sensitivity (LODs).
"Adduct formation in LC-MS Analysis (esp. ESI)"; https://hplctips.blogspot.com/2011/12/adduct-formation-in-lc-ms-analysis-esp.html
Eef Dirksen Mohammed Almajidi William Letter Oh, thank you for the reply! It is so helpful for me to analyze the data!! I really appreciate the reply! Thank you so much!
The answer of Eef Dirksen is rather complete. Glassware and the initial sample itself are the most common source of Na+, also K+ for natural compounds. Even very low concentrations can give adducts because some molecule have a high affinity for alkali metal ions. When there is a doubt about a m/z (is it M+23 ?) you may add Li+ and check for the expected M+7. I'd like to add that if you work close to the sea, the environmental dust is also a source of NaCl.
HPLC grade water can contain sodium. Excess sodium can suppress protein signsls in ESI. Use an 18-megOhm water purifier.
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