Selection of Internal Standards for Quantitative Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Biochemistry

Background:

• Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) is widely used for qualitative analysis of organic and biological molecules.
• Quantitative MALDI MS is challenging due to the limited availability of isotope-labeled internal standards.

Purpose of the Study:

• To investigate the relationship between correlation coefficients of peak intensities and quantitative analysis linearity in MALDI MS.
• To establish a method for selecting non-isotope-labeled internal standards for quantitative MALDI MS.

Main Methods:

• Analyzed the correlation coefficient between analyte and candidate internal standard ion peak intensities.
• Evaluated the linearity of quantitative analysis using selected non-isotope-labeled internal standards.
• Used ciprofloxacin and substance P as analyte examples.

Main Results:

• A high positive correlation coefficient (>0.7) between analyte and standard ions indicates good linearity (R^2 > 0.98).
• The performance of non-isotope-labeled internal standards is strongly linked to the correlation coefficient.
• Demonstrated the principle with ciprofloxacin and substance P.

Conclusions:

• A high correlation coefficient is a reliable indicator for selecting non-isotope-labeled internal standards in MALDI MS.
• This approach facilitates rapid quantitative mass spectrometry by simplifying internal standard selection.
• Offers a new strategy for quantitative MALDI MS analysis.