Samples described in Section 2.2 were analyzed by the proposed
method. The results obtained are summarized in Table 3,
and as it can be seen, the values found agree well with those
reported by the producer and with those obtained by a head
space-gas chromatography with FID detection method developed
in our laboratory [25] and by an alternative derivative FTIR
procedure (see Section 2.3.1) [18]. The results obtained show
that the proposed FI–FTIR determination of ethanol provides a
fast, precise, and accurate means for the analysis of ethanol in
alcoholic beverages.
The regression found between the values obtained by the
proposed method and those reported by the producers was
Y = 0.118 + 0.998 with r = 0.9999. In the same way, the regression
between values obtained by the proposed method (Y)
and those obtained by two different alternative procedures
(X: HP-GC-FID and derivative FTIR) provides the following
regression equations: Y = 0.081 + 0.9946 with r = 0.9997 and
Y = 0.051 + 0.9965 with r = 0.9998, respectively; which demonstrate
that the method does not require a blank correction,
because the intercept is statically equal to 0. Results also indicate
that the method is free of constant relative errors, because
the slope is statistically equal to 1 [32].