title: Mass determination of megadalton-DNA electrospray ions using charge detection mass spectrometry.
abstract: Charge detection mass spectrometry (CD-MS) has been used to determine the mass of double-stranded, circular DNA and single-stranded, circular DNA in the range of 2500 to 8000 base pairs (1.5-5.0 MDa). Simultaneous measurement of the charge and velocity of an electrostatically accelerated ion allows a mass determination of the ion, with instrument calibration determined independently of samples. Positive ion mass spectra of electrosprayed commercial DNA samples supplied in tris(hydroxymethyl)ethylenediaminetetraacetic acid buffer, diluted in 50 vol. % acetonitrile, were obtained without cleanup of the sample. A CD mass spectrum constructed from 3000 ion measurements takes 10 min to acquire and yields the DNA molecular mass directly (mass resolution = 6). The data collected represent progress toward a more automatable alternative to sizing of DNA by gel electrophoresis. In addition to the mass spectra, CD-MS generates charge versus mass plots, which provide another means to investigate the creation and fate of large electrospray ions.
authors: Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA. jcschultz@lbl.gov.
authors: J C
authors: JC
authors: Schultz
authors: Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
authors: C A
authors: CA
authors: Hack
authors: Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
authors: W H
authors: WH
authors: Benner