can use ammonium chloride in LCMSMS-ESI-?

[hoangduc]

We are developing method for determining a drug compound in human plasma by lcmsms. We considered some adduct solution. Result: with ammonium chloride as adduct (-) intensity is maximum. However, i don't know Can ammonium chloride cause corrosion problem?

[JMB]

The Cl anion is notoriously corrosive to stainless steel, and it is usually recommended by HPLC manufacturers to either avoid it or flush the HPLC pumps/lines very thoroughly after use.

If you can set up the runs to include such flushing at the end of the batch, then you will be OK.

The ESI-MS source should not be affected, but as a guess (I have not run multiple LC/MS with Cl anion present) the capillary may age a little faster than usual.

[gapeev]

I used NH4CL as an HPLC additive at about 1 ppm concentration for LC-MS ESI(-) runs. Even published some papers. No problems noticed. And yet, Cl(-) won't do no good to your LC. We HAD to use it to get all the analytes s into the [X]Cl- form. Cl(-) is not a LC friend for sure.

Where it boils down to is that using little of PURE NH4Cl followed by water rinse at the end of a batch won't hurt.