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14 min.
LC_0197
PeakList:
1.
α
-tocopherol
2.
β
-tocopherol
3.
γ
-tocopherol
4.
δ
-tocopherol
Sample:
Inj.:
10µL
Conc.:
approx. 1.25% soy oil
Solvent:
hexane
Column:
Pinnacle
II
™
Silica
Catalog #:
9210565
Dimensions:
150 x 4.6mm
Particle Size: 5µm
Pore Size:
110Å
Conditions:
Mobile Phase: isopropyl alcohol:hexane
(0.5:99.5)
Flow:
0.6mL/min
Temp.:
30°C
Det.:
UV@295nm
APinnacle II
™
silica column effectively separates the positional isomers of tocopherol by normal phaseHPLC.
Figure 7
HPLC using a Pinnacle II
™
silica column shows how effectively
these positional isomers can be separated (Figure 7). These
compounds can be quantified using either fluorescence or
UV detection.
Summary
Preservatives areadded toawide rangeof products tohelpmain-
tain theoverall qualityof theproduct aswell as toextend its shelf
life.The level of eachpreservativecompoundpresent needs tobe
monitored for several reasons. First, becausemanyof theseprod-
uctsareconsumed, thepreservativecontent needs tobemeasured
to ensure a safe level. Second, the stated shelf-life is dependent
upon a certain concentration of preservatives and incorrect
concentrations can lead to premature spoilage of the product.
HPLC is a powerful tool for analyzing preservatives in a wide
range of consumer products. One of its benefits is that many
times only minimal sample preparation is required.
Chromatographic techniques allow analysts to separatepreserva-
tives fromother compounds in the samplematrix, improving the
overall quality of the results. The Pinnacle II
™
line of HPLC
columns is an excellent choice for the analysis of preservative
compounds such as parabens, benzoate and sorbate salts, pheno-
lic antioxidants, and tocopherols. Pinnacle II
™
columns are avail-
able in a range of stationary phases, includingC18, C8, phenyl,
amino, and silica. For analyzingorganicacids, theUltraAqueous
C18 column is theperfect choice, offering superior retention and
reproducibility for polar compounds, even when using highly
aqueousmobile phases.
References
1.Fennema, OwenR. FoodChemistry (1996),Marcel Dekker,
NewYork.
2.Nollet (ed.), FoodAnalysis byHPLC (2000), 2nd edition,
Marcel Dekker, NewYork.
3.Foulke, JudithE. "AFreshLook at FoodPreservatives" in
FDAConsumer (October 1993), US. Food&Drug
Administration.
Additional Restek literature can be found
on our website at
Foods, flavors, and fragrances
Products and applications for
GC andHPLCanalysis.
Literature cat.
#59260
HPLCColumns and Accessories
Products and applications for
HPLC and LC/MSanalysis.
Literature cat. #
59241
