Sensitivity improvement achieved by acetyl-derivatization in atmospheric pressure chemical ionization-mass spectrometry.

A method of increasing the detection response by acetyl-derivatization on atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) has been investigated. By acetylation on compounds having primary alcohol, primary amine and phenolate, it was found that the detection responses of their acetylated forms were increased by 2 to 5 fold over their intact forms. This suggests that acetyl-derivatization was an effective method of increasing response on APCI-MS for compounds having these groups. A possible reason is that acetylation caused increased proton affinity (PA). So, PA should be well considered when trying to increase the response on APCI-MS by derivatization. This acetyl-derivatization method seems promising for increasing the response on LC/APCI-MS.