Optimization of LC/MS (APCI)+ Methods for the Determination of Possible Lutein Oxidation Products in Plasma and Tissues of Adult Rats.

In spite of lutein and its isomer zeaxanthin
being richly available in natural sources, the role of these
components on reduction of age-related macular degeneration,
cancer, and cardiovascular disorders suggested that an
update of the analytical procedure is required to determine
the oxidative products and to understand their nutritional
significance. In the present study, we have standardized and
developed an improved method to obtain characteristic ions
of lutein, zeaxanthin, and its major oxidative products in
vivo (rats) using LC–MS (APCI)+. In addition, lutein and
zeaxanthin isomer were separated on a C30 column with
shorter run time with high resolution and calibrated on the
basis of picomolar concentration on HPLC (DAD), with
the lower detection limit of 0.125 for lutein and 0.128 pmol
for zeaxanthin. Characteristic mass spectral ion for lutein
is m/z 568.7 [M]+ and 551.5 [M + H–H2O]+ and for zeaxanthin
isomer is m/z 568.8 [M]+, 569.8 [M + H]+. Further,
optimized conditions produced structurally characteristic
fragmented ions under standardized MS (APCI)+ conditions.
Total ionic chromatogram together with fine UV–
Visible and mass spectra were used to differentiate lutein
isomers and its oxidative products, such as 523 [M+ + H+–
3CH3], 479 [M+ + H+–6CH3], 551 [M+ + H+–H2O],
276.43 [M+–C22H19O], di-epoxides and 3′-oxolutein. The
APCI mass spectral characteristics of major oxidative products
of lutein in adult rat tissues are reported here for the
first time, to our knowledge. These findings could provide new insights into lutein bioavailability and bioconversions
with respect to health benefits.