2 research outputs found
Long-Term Performance and Stability of Molecular Shotgun Lipidomic Analysis of Human Plasma Samples
The stability of the lipid concentration
levels in shotgun lipidomics
analysis was tracked over a period of 3.5 years. Concentration levels
in several lipid classes, such as phospholipids, were determined in
human plasma lipid extracts. Impact of the following factors on the
analysis was investigated: sample amount, internal standard amount,
and sample dilution factor. Moreover, the reproducibility of lipid
profiles obtained in both polarity modes was evaluated. Total number
of samples analyzed was approximately 6800 and 7300 samples in negative
and positive ion modes, respectively, out of which 610 and 639 instrument
control samples were used in stability calculations. The assessed
shotgun lipidomics approach showed to be remarkably robust and reproducible,
requiring no batch corrections. Coefficients of variation (CVs) of
lipid mean concentration measured with optimized analytical parameters
were typically less than 15%. The high reproducibility indicated that
no lipid degradation occurred during the monitored time period
Differential Mobility Spectrometry-Driven Shotgun Lipidomics
The analysis of lipids by mass spectrometry
(MS) can provide in-depth
characterization for many forms of biological samples. However, such
workflows can also be hampered by challenges like low chromatographic
resolution for lipid separations and the convolution of mass spectra
from isomeric and isobaric species. To address these issues, we describe
the use of differential mobility spectrometry (DMS) as a rapid and
predictable separation technique within a shotgun lipidomics workflow,
with a special focus on phospholipids (PLs). These analytes, ionized
by electrospray ionization (ESI), are filtered using DMS prior to
MS analysis. The observed separation (measured in terms of DMS compensation
voltage) is affected by several factors, including the <i>m</i>/<i>z</i> of the lipid ion, the structure of an individual
ion, and the presence of chemical modifiers in the DMS cell. Such
DMS separations can simplify the analysis of complex extracts in a
robust and reproducible manner, independent of utilized MS instrumentation.
The predictable separation achieved with DMS can facilitate correct
lipid assignments among many isobaric and isomeric species independent
of the resolution settings of the MS analysis. This leads to highly
comprehensive and quantitative lipidomic outputs through rapid profiling
analyses, such as Q1 and MRM scans. The ultimate benefit of the DMS
separation in this unique shotgun lipidomics workflow is its ability
to separate many isobaric and isomeric lipids that by standard shotgun
lipidomics workflows are difficult to assess precisely, for example,
ether and diacyl species and phosphatidylcholine (PC) and sphingomyelin
(SM) lipids