PrecursorIon

Remarks

The precursor ion of a dependent scan and how it was isolated and fragmented. A spectrum holds zero or more in its Precursors list.

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Constructors

Syntax	Description
PrecursorIon()	Creates an empty precursor.
PrecursorIon(PrecursorIon pi)	Copy constructor.
PrecursorIon(double mz, double intensity = 0, int charge = 0, double isoMz = 0, double isoWidth = 0)	Creates a precursor from its monoisotopic m/z, with optional intensity, charge, isolation m/z and isolation width.

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Properties

Identifier	Type	Description
Charge	int	Charge state of the precursor.
CollisionEnergy	double	If a dependent scan, the fragmentation energy used.
FragmentationMethod	FragmentationType	The fragmentation method used, or FragmentationType.None if not known.
Intensity	double	Intensity of the IsolationMz precursor peak.
IsolationMz	double	The m/z that the instrument targeted for isolation.
IsolationSpecificity	double	Proportion of the intensity in the isolation window that belongs to the precursor, from zero to one.
IsolationWidth	double	The size of the window that the instrument targeted for isolation.
MonoisotopicMz	double	The putative monoisotopic m/z peak of the isotope envelope that contains the isolation m/z.

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Methods

Method	Returns	Description
Clear()	void	Resets all values to 0.

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Example

using Nova.Data;
using Nova.Io.Read;

FileReader reader = new FileReader("DDA.raw", MSFilter.MS2);
foreach (Spectrum spectrum in reader)
{
  foreach (PrecursorIon precursor in spectrum.Precursors)
  {
    Console.WriteLine(precursor.MonoisotopicMz + "\t" + precursor.Charge
      + "\t" + precursor.FragmentationMethod);
  }
}

PrecursorIon precursor = new PrecursorIon(652.3412, 1.2e6, 2, 652.84, 1.6);
precursor.FragmentationMethod = FragmentationType.HCD;

// The copy constructor carries every field.
PrecursorIon copy = new PrecursorIon(precursor);