Journal of Lipid Research, Vol 37, 2450-2460, Copyright © 1996 by Lipid Research, Inc.
Quantitation of individual phospholipid molecular species by UV absorption measurements
J McHowat, JH Jones and MH Creer
Department of Pathology, University of Arkansas for Medical Sciences, Little, USA.
To validate the utility of on-line measurements of UV absorption for the
direct quantitation of individual phospholipid molecular species isolated
by reverse-phase HPLC, we synthesized 37 different individual molecular
species of diacyl choline glycerophospholipids. UV absorbance response
factors (integrate UV absorbance/nmole phospholipid) were calculated for
all diacyl, alkenylacyl, and alkylacyl species by injecting varying amounts
of the purified molecular species in the 2- 100 nmole range and integrating
the UV absorbance at 203 nm. There was excellent agreement between the
results of the quantitation of individual molecular species determined by
measurements of phospholipid mass in HPLC fractions with that based on
measurements of total integrated UV absorption and the use of absorbance
response factors. The on-line quantitation of individual phospholipid
molecular species by UV absorption measurement should prove useful as an
adjunct to other techniques of phospholipid quantitation, as a means to
assist in the identification of individual molecular species in complex
biologic mixtures, and as a stand-alone approach to phospholipid
quantitation to facilitate studies of the metabolism of individual species
particularly when coupled with radiolabeling techniques.