Wm. Craig Byrdwell, phd

Resources for Lipid Analysis in the 21st Century

This is a Phosphatidyl Inositol (PI) molecule. This PI contains an 18:2 (linoleic acid) fatty acyl chain and an 18:0 (stearic acid) acyl chain. It is (SL)-PI. Phosphatidyl Inositols readily form deprotonated molecules, [M-H], by electrospray ionization mass spectrometry (ESI-MS) in negative-ion mode. By positive-ion ESI-MS/MS and APCI-MS, this PI forms the diacylglycerol-like fragment ion [SL]+ and other fragments.

PhosphatidylInositols Home

This page has been established to disseminate free copies of mass lists of PhosphatidylInositols, or Phosphatidyl Inositol (PI) molecular species, also called GlycerophosphoInositols (GPIns).

Mass lists from these pages pertain to analysis of PhosphatidylInositols by atmospheric pressure chemical ionization (APCI)  and electrospray ionization (ESI) mass spectrometry (MS) techniques:


Data are given for Phosphatidyl Inositol protonated molecules, lithium, sodium and potassium adducts, diacylglycerol-like fragment ions, and fatty acid-related fragments.  Unlike amine-containing phospholipids, PhosphatidylInositols are best observed in Negative Ion (–) mode.

Mass lists are given as:

1.  Fatty Acid and Fatty Acid Methyl Ester mass list.

2.  Phosphatidyl Inositol & Fragment Masses by PI name.

3.  Phosphatidyl Inositol & Fragment Masses by PI mass.

4.  Masses of Adducts of PhosphatidylInositols by PI name.

5.  Masses of Adducts of PhosphatidylInositols by PI mass.

These tables were put together by Dr. Byrdwell in the course of more than a decade of working on lipid analysis.

These mass lists are provided here as a service to my colleagues.


Please report any errors in these pages to Byrdwell@Byrdwell.com

To contact me:

Wm. Craig Byrdwell, Ph.D.

Beltsville, MD  20705


E-mail: Byrdwell@Byrdwell.com

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Disclaimer:  Not all fragments or adducts listed here are observed from every class of phospholipid.  Every possible adduct and most fragments have been listed here for the sake of thoroughness, whether they are actually observed or not. The page for each phospholipid class will be tailored as time permits.

© 2005-2011

The figures and tables on this website are copyrighted in 2005-2011 by William Craig Byrdwell and Byrdwell.com.  Please reference



Disclaimer 2:  The information provided here is not approved by, sanctioned by or paid for by Dr. Byrdwell’s employer.  They are not responsible for its content.  Advertisements may appear on some pages to help defray the costs of website publication and maintenance.