Using a triple-quadrupole mass spectrometer in accurate mass mode and an ion correlation program to identify...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Chemical Analysis

Background:

• Atomic masses and isotopic abundances are crucial for distinguishing ion compositions.
• Accurate mass measurements and relative isotopic abundance (RIA) data significantly reduce possible ion formulas.
• Inherent interferences in mass spectra can distort RIA measurements.

Purpose of the Study:

• To evaluate the efficacy of combining accurate mass and RIA measurements for unique ion composition determination.
• To address and overcome inherent interferences affecting RIA measurements in mass spectrometry.
• To demonstrate a method for compound identification in the absence of commercial spectral libraries.

Main Methods:

• Utilized a triple-quadrupole mass spectrometer with accurate mass capability and atmospheric pressure chemical ionization (APCI).
• Measured exact masses and RIAs of precursor and fragment ions for nine simulated unknown chemicals.
• Employed an ion correlation program to reconcile elemental compositions between precursor ions, fragment ions, and neutral losses.

Main Results:

• Accurate mass (6-10 mDa) and RIA (10%) measurements were sufficient for unique precursor ion composition determination.
• The ion correlation program effectively managed inherent interferences, allowing for accurate RIA analysis.
• Unique compositions were determined for all precursor ions and most fragment ions, compensating for the lack of spectral libraries.

Conclusions:

• Combining accurate mass and RIA measurements provides a robust method for ion composition determination.
• The developed approach offers a viable alternative for compound identification when spectral libraries are unavailable.
• This technique enhances the reliability of mass spectrometry in analyzing complex chemical samples.