OrganicAcids inFruit Juice
HPLC
Allure™OrganicAcids
ShortChainAcids
GC
Rtx®-1
(direct injection)
GC_CH00281
min.
4
8
1
2
3 4
5
6
7 8 9
30m, 0.53mm ID, 5.0µmRtx
®
-1 (cat.# 10179)
0.2µL injection of a 10–20ng/µL free fatty acid
standard inwater. Direct injection using a
Uniliner
®
liner.
Oven temp.:
60°C to 180°C@15°C/min.
Inj. & det. temp.:
250°C
Carrier gas:
hydrogen
Linear velocity:
50cm/sec.
(flow rate: 6cc/min.)
FID sensitivity:
4 x 10
-11
AFS
Peak List:
1. acetic acid
2. propionic acid
3. isobutyric acid
4.
n
-butyric acid
5. isovaleric acid
6.
n
-valeric acid
7. isocaproic acid
8. caproic acid
9. heptanoic acid
FOODS, FLAVORS,
& FRAGRANCES
15
Organic Acids
Phone: 800-356-1688 or 814-353-1300
The organic acid content of fruit juices, such as
cranberry and grape, can be determined using
AOACmethod986.13. Because several of the acids
are extremely difficult to resolve, this procedure
calls for two reversedphaseC18 columns in series,
on a 100% aqueousmobile phase.
A single 30cm
Allure™ Organic Acids
column
effectively resolveskeyorganicacids, suchas tartar-
ic and quinic, using the chromatographic condi-
tions specified inAOACmethod986.13!
Organic acids also can be analyzed byGC. Shorter
chain, volatile free fatty acids such as acetic, propi-
onic, butyric, and valeric acids can be analyzed
using a
Stabilwax®-DA
column, a bonded
Carbowax
®
column specifically deactivated for
acidiccompounds.Direct injectiongenerally is rec-
ommended, to avoid losing volatile lowmolecular
weight free fatty acids through the split vent, thus
improving reproducibility.
Less polar columns, such as Rtx®-1 and Rtx®-200
(page 2), can be used to separate short chain acids.
However, thicker films are required to improve sep-
arationand increase sample capacity forpolar com-
pounds.
Peak List:
Conc. (mg/mL)
1. tartaric acid
1
2. quinic acid
1
3. malic acid
1
4. citric acid
1
5. fumaric acid
0.005
Sample:
Inj.:
10µL standard solution
Solvent:
water
Column:
Allure
™
Organic Acids
Cat.#:
9165585
Dimensions:
300 x 4.6mm
Particle size:
5µm
Pore size:
60Å
Conditions:
Mobile phase:
100mM phosphate buffer, pH 2.5
Flow:
0.5mL/min.
Temp.:
ambient
Det.:
UV@ 226nm
LC_0238
Stabilwax®-DA
(split injection)
30m, 0.25mm ID, 0.25µm Stabilwax
®
-DA (cat.# 11023)
1.0µL split injection of a free acid standard.
Concentration approximately 10 to 20ng/µL.
Oven temp.:
145°C
Inj. & det. temp.:
250°C
Carrier gas:
hydrogen
Linear velocity:
40cm/sec.
FID sensitivity:
2 x 10
-11
AFS
Split ratio:
50:1
GC_CH00280
min.
4
8
12
9
8
7
6
5
4
1
3
2
dependable
execution
A single 30cmAllure
™
Organic Acids column
resolves key organic acids.
min.
for
more
info
Request ApplicationNotes AnalyzePolar Compounds by Reversed
PhaseHPLC, UsingUltraAqueous C18Column (cat.# 59177) and
SingleColumnMethod for HPLCAnalysis of Organic Acids in Fruit
Juices, Using anAllure
™
Organic Acids Column (cat.# 59530).
