Figure 1: Chromatogram of 5 standard saccharides (1000 mg/L
In this present application, monosaccharides and disaccharides in soft
drinks were separated in short time by hydrophilic interaction chromatography
(HILIC) and were detected by ELSD. The “wide function”, a new feature
of the ELSD-LT III used in this case, automatically optimizes a parameter
that is related to sensitivity, and a single analytical run can be applied
for data acquisition regardless of sample concentration, from low to high.
Analysis of 5 standard
Table 1 describes the analytical conditions for 5 standard compounds of
different saccharides (fructose, glucose, sucrose, maltose, lactose). Figure
1 shows the chromatogram obtained, with good separation for the
5 standard saccharides with a concentration of 1000 mg/L for each compound.
It is recommended to wash the column well before use, and after
injection the 5 saccharides elute within 5 minutes by gradient elution.
Table 2 lists the repeatability confirmed by repeated analyses at 250
mg/L (n=6) with convincing results for the relative standard deviation
for retention time and area for all saccharides.
Figure 2 shows the calibration curves and table 3 the concentration
ranges of the compounds. The response of ELSD was plotted on double
logarithmic axes because the logarithms of the ELSD response and
the concentration are in proportion. The calibration curves of fructose
and glucose were created using the same 6 concentrations and for the
other disaccharides sucrose, maltose and lactose a different range of
6 concentrations was applied.
High-Speed analysis of 5 saccharides
in soft drinks
This analysis was carried out under the same analytical conditions as
described in table 1. For soft drink A, figure 3 shows the chromatogram
of the analysis, and table 4 lists the determination result of saccharides.
The sample was filtered with a 0.2 μm membrane filter and
diluted 20 times with water/acetonitrile (50:50) for analysis.
Figure 4 shows the chromatogram of the soft drink B, and table 5
the determination result of saccharides. After filtration with a 0.2 μm
membrane filter and 20 times dilution with water/acetonitrile (50:50),
the obtained supernatant was analyzed. The 5 saccharides were
detected without sensitivity adjustment, applying the “wide function”
Figure 2: Calibration curves.
Figure 3: Chromatogram of soft drink A.
Figure 4: Chromatogram of soft drink B.