Waters Soft Drink Analysis Kit - Manual (Page 2)

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[ Care and Use ManUal ]
30 mm ID Preparative Guard Cartridges and Guard Holders
II. usIng the Waters soft drInk analysIs kIt
a. Preparing the standards solution
Prepare the standards solution by mixing CBS standard and
aspartame. Prepare fresh standards solution weekly.
1. Select a flask suitable for preparing 200 mL of solution.
Weigh to ± 0.1 g. Leave the flask on the scale.
2. Record the empty weight of the flask. Add 194.8 to that
number, and record the result.
3. Empty one vial of aspartame into the flask. Rinse the empty
vial with CBS standard, and empty the vial into the flask.
Repeat twice.
4. Add CBS standard to the flask until the combined weight of the
flask and the solution reaches the value calculated in step 2.
(The combined weight of the CBS standard and aspartame is
194.8 g).
5. Mix well. Vacuum filter the solution through a 0.45 μm filter
into a labeled storage container and refrigerate. The standards
solution prepared by this method contains:
■ ■
Caffeine 100 mg/L
■ ■
Aspartame 500 mg/L
■ ■
Benzoate 200 mg/L
■ ■
Sorbate 100 mg/L
Please note that each lot of WAT036889 standards will have its
own verified concentration of caffeine, benzoate and sorbate. The
values on the product label indicate the actual concentration of
caffeine, benzoate & sorbate for that specific lot.
These values should be used as the component amounts when
entering values for each analyte for the standard curve. The
Aspartame concentration is 500 mg/L for all lots if prepared as
directed.
b. replacing Mobile Phase
Circulate one liter of mobile phase for one week. To replace mobile
phase, purge the old mobile phase from the system and replace it
with fresh mobile phase. To prime and start the pump, refer to the
pump operators manual.
1. Set the pump flow rate to 0.0 mL/min
2. Remove the waste line from the solvent reservoir. Place the
line into a waste container.
3. Put the solvent line into the new bottle of mobile phase.
4. Set the pump flow to 1.0 mL/min and wait 15 minutes.
5. Monitor the detector for stability. When stable, return the
waste line to the solvent reservoir to recirculate. Monitor
the detector for stability. When stable inject a standard to
recalibrate the instrument.
6. Use the same mobile phase for one week. Replace the mobile
phase weekly.
c. Instrument settings
Figure 2 is a chromatogram of a standards solution. The table
below shows the settings used to obtain the chromatogram.
soft drink analysis with Breeze
1
2
3
4
8 min 7 6 5 4 3 2 1 0
System: Breeze with 2487 UV Detector
Sample: Waters Standards for Soft Drink Analysis
Buffer: Waters Mobile Phase for Soft Drink Analysis
Column: Nova-Pak ® C
18
, 4 μm, 3.9 x 150 mm Column
Injection volume: 20 μL
Flow rate:
1.0 mL/min
Temperature: 35 °C
Detection: UV@ 214 nm
compounds:
1. Caffeine 100 mg/L
3. Benzoate 200 mg/L
2. Aspartame 500 mg/L 4. Sorbate 100 mg/L
Figure 2: Chromatogram of a standards solution
III. storage
Store mobile phase at room temperature indefinitely. Refrigerate
standards solution. Make fresh standards solution weekly.