• DOI:10.1080/00032719.2012.693140
• Corpus ID: 94856841

Understanding the Charge Issues in Mono and di-Quaternary Ammonium Compounds for Their Determination by LC/ESI-MS/MS

@article{Velpandian2012UnderstandingTC,
  title={Understanding the Charge Issues in Mono and di-Quaternary Ammonium Compounds for Their Determination by LC/ESI-MS/MS},
  author={Thirumurthy Velpandian and Jayabalan Nirmal and Beauty Arora and Alok Kumar Ravi and Ankita Kotnala},
  journal={Analytical Letters},
  year={2012},
  volume={45},
  pages={2367 - 2376}
}

• T. Velpandian, J. Nirmal, +2 authors A. Kotnala
• Published 17 May 2012
• Chemistry
• Analytical Letters

Chromatographers often develop problems while optimizing a method for the quantification of quaternary ammonium compounds in ESI-MS/MS. Intransigency observed in quaternary ammonium compounds to undergo the classical molecular adduct formation [M+H]+ in ESI-MS/MS reduces confidence among chromatographers while working with unit mass resolution. In this study, we provide the evidence for an exceptional rule followed by mono- and di-quaternary ammonium compounds in ESI-MS/MS in the precursor ion formation. Under ESI conditions mono- and di-quaternary ammonium compounds form molecular ions with the formula of m q / z q rather than ( m + z )/ z . Formation of m q / 2 is observed for di-quaternary ammonium compounds in precursor ion scan and m q / 1 in product ion scan, if loss of one of the quaternary charge occurs during CID. In di-quaternary ammonium compounds, this process can also result in the formation of fragment ions with higher mass as compared to precursor ion. Hydrophilic interaction liquid chromatographic separation has been used to demonstrate the elution of quaternary ammonium compounds in a single run in the ESI-MS/MS. This work concludes that the analyst must realize and consider these charge issues while dealing with positively charged compounds in LC/ESI-MS/MS.