Hi Matt, how about for CID spectra? Is there charge prediction available?

-LW

On Monday, July 11, 2011 9:51:31 AM UTC-7, matt.chambers wrote:
>
> The chargeStatePredictor filter in msconvert will do the standard 
> single/multiple guessing or ETDZ 
> prediction for ETD MSn spectra. I.e. --filter "chargeStatePredictor false 3 
> 2 0.9"
>
> -Matt
>
>
> On 7/11/2011 11:40 AM, Jimmy Eng wrote:
> > Greg, the precursorCharge attribute is only present for data where the
> > charge state is present in the raw file.  This usually is true for
> > FT/Orbi data but not normally with LTQ/Velos data.
> >
> > Robert, the real question is what precursor charge would you want to
> > be associated with each ms/ms spectrum for your LTQ Velos spectra?
> > Since there's no precursor charge in the underlying RAW file, the
> > converters won't make them up. It's not inconceivable to implement
> > charge state guessing rules, like those implemented in Tandem, but I'm
> > not sure this is going to happen for many reasons.
> >
> > On Mon, Jul 11, 2011 at 9:29 AM, Greg Bowersock<[email protected]> 
>  wrote:
> >> Precursor charge is already in mzXML. If you look at the mzXML files 
> created
> >> by ReAdW (msconvert should also have it), you should see lines such as:
> >> <precursorMz precursorIntensity="2123.5" precursorCharge="4"
> >> activationMethod="CID">1390.82</precursorMz>
> >> Those lines are part of the msms scan information (ms level = 2). If the
> >> line isn't there, you might want to check the method on LTQ to make sure
> >> that Charge State Screening is enabled for the segment in the dependent 
> scan
> >> settings.
> >> Greg
> >>
> >> On Mon, Jul 11, 2011 at 11:06 AM, Robert<[email protected]>
> >> wrote:
> >>>
> >>> Hi,
> >>>
> >>> when converting Thermo (LTQ velos) raw files to mzXML, no precursor
> >>> charges are included in the resulting mzXML. I tried ReAdW (TPP) and
> >>> msconvert (Proteowizzard).
> >>>
> >>> This is not a problem for X!Tandem searches, but for some uses
> >>> (calculation of mass errors, PRIDE XML repository), the precursor
> >>> charge would be desirable.
> >>>
> >>> Any suggestions, how the charge could be added to mzXML?
> >>>
> >>> Best, Robert
>
>

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