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chromatographic gradient (2-40% acetonitrile).
With respect to how the transition data was
processed and analyzed, particularly with respect to
the quantitative analysis, some aspects require
additional information. The authors seem to
recommend quantification by developing a specific
calibration curve for each allergenic food target and
food matrix combination, using incurred/spiked
foods. The quantification calibration curve would
utilize a ratio of the spiked/incurred peptide peak
area to the peak area of an internal heavy standard
peptide spiked in following sample digestion. The
concentration in an unknown sample would be
determined by including the heavy internal
standard peptide prior to analysis, and determining
the subsequent light(sample):heavy peak area ratio
and comparing that to the calibration curve. What
remains unclear is how an end user would
implement this calibration curve process in order to
conduct the method. Will the end user need to
analyze the spiked food calibration curve on their
own instrument? If so, will the method developers
provide the calibration curve materials? Also, how
similar must the calibration curve food matrix be to
the unknown sample food matrix? The authors have
only shown information about the one set of food
matrices that they prepared for the calibration
curve itself, not for other food products. It remains
quite unclear how an end user would conduct the
quantitative analysis. In addition, the authors did
not provide much information about how each
transition and/or peptide would be evaluated either
qualitatively or quantitatively in this system. For
example, is the sum of the individual peptide
transitions utilized for the peak area calculations?
Are both transitions for each peptide required? In
addition, it is unclear how many peptides and
transitions are actually monitored and quantified in
the final method. It is initially stated that two
transitions are monitored from two peptides