EPA Science Inventory

CAPILLARY ELECTROPHORESIS-ELECTROSPRAY MASS SPECTRA OF THE HERBICIDES PARAQUAT AND DIQUAT

Contact
WILLIAM L BUDDE
phone: 5135697309
email: budde.william@epa.gov


Citation:

Song, X. AND W. Budde. CAPILLARY ELECTROPHORESIS-ELECTROSPRAY MASS SPECTRA OF THE HERBICIDES PARAQUAT AND DIQUAT. Journal of the American Society for Mass Spectrometry 7(9):981-986, (1996).

Description:

The positive ion electrospray mass spectra of the quaternary ammonium salt herbicides paraquat and diquat are examined by on-line separation with capillary electrophoresis (CE) and by direct infusion of the analytes. The analytes are separated by CE in 7-10 min at pH 3.9 in 50% methanol-water by using several differenct separation buffer electrolytes. The capillary electrophoresis-eletrospray ionization (CE-ES) mass spectra of paraquat and diquat consist primarily of doubly charged molecular ions, singly charged molecular ions, and singly charged deprotonated ions. The direct infusion spectra consist primarily of doubly charged molecular ions and signly charged deprotonated ions. The relative abundances of the doubly charged and deprotonated ions depends strongly on the presence or absence of ammonium ion in the CE separation buffer or the direct infusion solution. A deprotonation mechanism is proposed in which the free base ammonia is the deprotonating agent in the desolvating charged dropkets or in the gas phase. The analytical potential of the CE-ES electrospray approach for environmental analyses is evaluated in terms of the precision of replicate injections, linear concentration range, and estimated detection limit.

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 09/01/1996
Completion Date: 09/01/1996
Record Last Revised: 12/22/2005
Record Created: 04/26/2000
Record Released: 04/26/2000
Record ID: 13982

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT