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Mecanismo de carga y sobrecarga de moléculas en la ionización por electrospray
Anthony T Iavarone1, Evan R Williams
1Contribution from the Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|February 20, 2003
Resumen
La tensión superficial de las gotas de electrospray tiene un impacto significativo en la carga del analito. Este estudio apoya el mecanismo de residuos cargados para la formación de iones cargados múltiples en la ionización por electrospray.
Área de la Ciencia:
- Química Analítica La Química Analítica es la
- Química Física es la química física.
- Espectrometría de masas por espectrometría de masas.
Sus antecedentes:
- El mecanismo de formación de iones cargados múltiples en la ionización por electrospray (ESI) es un debate de larga data.
- Los factores que influyen en el estado de carga de los iones analíticos en ESI son complejos y no se comprenden completamente.
Objetivo del estudio:
- Investigar el papel de la tensión superficial del disolvente en la determinación del grado de carga para varios analíticos en ESI.
- Proporcionar evidencia que apoye o refuta los mecanismos de formación de iones existentes en el ESI.
Principales métodos:
- Ionización por electrospray de dendrímeros de polipropilenoimine, citocromo c, polietilenglicol y 1,n-diaminoalcanos a partir de soluciones con diferentes composiciones.
- Variación sistemática de la tensión superficial del disolvente mediante el uso de soluciones y mezclas de un solo componente, incluido el alcohol m-nitrobenzil (m-NBA).
- Análisis de correlación entre el estado de carga del analito y la tensión superficial del disolvente, y comparación con la carga límite de Rayleigh.
Principales resultados:
- El estado de carga del analito está significativamente correlacionado con la tensión superficial de la gota de electrospray al final del proceso de desolución.
- Adición de carga de analito alterado m-NBA basada en la tensión superficial de la solución inicial en relación con m-NBA.
- Se observó una fuerte correlación entre el estado de carga de los dendrímeros y 1,n-diaminoalcanos y su carga límite de Rayleigh calculada.
Conclusiones:
- Los resultados apoyan firmemente el mecanismo de residuos cargados como la vía principal para la formación de iones orgánicos de carga múltiple en ESI.
- El mecanismo de evaporación iónica parece desempeñar un papel menos significativo, particularmente para los dendrímeros y los 1,n-diaminoalcanos.
- La tensión superficial del disolvente es un factor crítico y cuantificable que influye en la carga iónica en la ionización por electrospray.
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