Quinic, malic, and citric acids in cranberry juice cocktail.
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Allure
™
OrganicAcids Column
Physical Characteristics:
particle size:
5µm, spherical,
non-endcapped phase
pore size:
60Å
pH range:
2.5 to 7.5
temperature limit: 80°C
Dimension
qty.
cat.#
300mmx 4.6mm
ea.
9165585
hand, contains quinic acid.A cranberry juice that containsmea-
surable amounts of tartaric acidwould be suspect. Thus, it is criti-
cal to both identify and quantify the organic acids in a fruit juice
to determine if the juice is described truthfully.
The organic acid content of fruit juices, such as cranberry juice
and apple juice, can be determined usingAOACmethod 986.13.
2
In this procedure, reversed phaseHPLCwith aUVdetector is
used to quantify organic acids. Because several of the organic
acids are extremely difficult to resolve, this procedure calls for
two reversed phaseC18 columns in series.A100% aqueous
mobile phase (phosphate buffer at pH 2.4) is used tomaximize
the interaction between the acids and the stationary phase.
Now there is a simpler andmore reliable approach.Asingle 30cm
Allure OrganicAcids column effectively resolves key organic
acids, such as tartaric and quinic acids, using the chromatographic
conditions specified inAOACmethod 986.13!
Figure 1 shows a separation of typical fruit juice organic acids,
including tartaric, quinic, malic, citric, and fumaric acids. Note
the baseline resolution between tartaric and quinic acids. This
superior performancemakes interpretation of analytical datamore
reliable. Similarly, note the distinct organic acid profiles for grape
juice and cranberry juice cocktail in Figures 2 and 3.
Analysis of polar organic acids can be difficult on conventional
reversed phase columns, evenwhen using highly aqueousmobile
phases and two reversed phase columns in series for the separa-
tion. In contrast, anAllure OrganicAcids column provides
enhanced retention and selectivity for these compounds, allowing
the separation to be performed on one 30cm column. Retention is
stable and reproducible, evenwith a 100% aqueousmobile phase,
as specified inAOACmethod 986.13. If you aremonitoring fruit
juice quality, andwant a trouble-free analysiswith accurate
results, we highly recommend anAllure OrganicAcids column.
References
1.
Authenticity of Apple Juice
Technical Bulletin #2 (1996),Analytical Chemical
Services of Columbia, Inc.
2.OfficialMethods ofAnalysis (2000),AOAC International, 17th edition, method
#986.13
.
Figure 3
PeakList:
1. quinic acid
2. malic acid
3. citric acid
Sample:
cranberry juice
Inj.:
10µL
Conc.:
cranberry juice:water
(50:50, v/v)
SampleDiluent: purifiedwater
Column and conditions same as Figure 1
LC_0236
HPLCCatalog
Ability tomanufacture silica, synthesizemany
stationary phases, and perform high-density
bonding hasmadeRestek a significant supplier
of HPLC columns. This 116-page catalog lists
columns in four silica lines, includingLC/MS
columns and other special-purpose columns,
microbore columns, and preparative columns.Many application
chromatograms. (lit. cat.# 59241A)
Foods, Flavors, & Fragrances
In-Review
Abstracts of 30+Restek publications on foods -
flavors - fragrances applications. Check the publi-
cations youwant on the pre-paid postcard - or
access them on our website. (lit. cat.# 59489)
citric acid
2000µg/mL
fumaric acid
10
malic acid
2000
quinic acid
2000
tartaric acid
2000
Inwater, 1mL/ampul
Each
5-pk.
35080
35080-510
Inwater, 5mL/ampul
Fruit JuiceOrganicAcidMixture
Foods, Flavors, & Fragrances
A 48-page overview of the foods, flavors, fra-
grances applications for whichRestekHPLC and
GC columns have been used.Applications include
amino acids, carbohydrates, chiral separations,
essential oils, fats and oils, organic acids, preserva-
tives, vitamins, andmore. (lit. cat.# 59260)
Each
5-pk.
35081
35081-510
