For HPLC analysis, two columns in series in
the K form are used (AminexHPX-87 K)
for optimal separation. The separations into
fructose, glucose, difructose-dianhydride
(DFA ), sucrose (GF ), F2 and F3 are optimal,
but further separation into DP 3, DP 4 and
DP 5 is not very precise. DP 3 and DP 4
fractions are not pure, but include GF2 plus
F4 and GF3 plus F5, respectively. The DP5
fraction is the integrated sum of DP 5 and
higher-DP molecules. As this fraction might
include small oligosaccharides as well as
high-DP inulins, a fixed response factor
cannot be determined, which makes this
analysis unsuited for quantitative inulin
determination. The method is well adapted
to evaluate the relative amounts of the
different compounds present, especially
the amounts of the non-inulin compounds
glucose, fructose and sucrose (Table 2).