Page 37 - LC-SFC_Pharma_Brochure

Samples showing high water content complicate the extraction pro- Six extraction vessels were prepared, each containing the same
cess (i.e., reduce both the extraction efÿciency and the repeatability amount of supplement sample. Each extraction vessel was subjected
of the pretreatment) as supercritical carbon dioxide does not mix to ofšine SFE after which the recovered liquid was analyzed by SFC at
with water. In these cases, the extraction efÿciency can be increased the conditions shown in Table 2. The recovery and repeatability of the
by mixing the sample with a dehydrating agent before enclosing it process was conÿrmed.
into the extraction vessel. Extraction efÿciency can also be low The six chromatograms obtained are shown overlapping each other
when supercritical carbon dioxide is used for the extraction of highly in Fig. 6.
polar constituents. In this case, the extraction efÿciency can be in-
creased by adding modiÿers such as methanol during the extrac- Table 2 Conditions Used for the Analysis of
tion. In the case of samples with constituents showing ionic polar the Pretreated Samples (SFC)
groups, acid (e.g., formic acid, acetic acid), salt (e.g., ammonium
formate, ammonium acetate), and bases (e.g., ammonia, diethyl- Column : Nacalai COSMOSIL Cholester

4.6 mmI.D. × 250 mmL. 3 Žm

amine) can be added during the extraction. Fine pulverization of the Modiÿer : IPA
sample normally increases extraction efÿciency. For polymer sam- Gradient : 2% (0 min) ĺ 20% (10 min) ĺ 50% (10–12 min)
ples, a ÿne freeze-crushing treatment before the extraction often Flow rate : 3 mL/min
results in increased extraction efÿciencies. Temperature : 40°C
Back pressure : 15 MPa
Injection volume : 2 ŽL
4. Using the Nexera UC SFE Pretreatment Detector : UV-VIS (@293 nm)
System for Extracting Fat-Soluble Vitamins
Vitamin E is a group of fat-soluble compounds widely used as antioxi- mAU
dants and for nutritional support in foods and medicinal products. d-α-tocopherol
We present an example of ofšine SFE using the Nexera UC SFE pre-
treatment system to extract d-α-tocopherol, a vitamin E compound, 20
from a nutritional supplement. The sample used was a commercially
available soft capsule supplement containing d-α-tocopherol. The
soft capsule supplement contained a paste, which was mixed with a
dehydrating agent before being enclosed into an extraction vessel.
The extraction was exclusively performed with supercritical carbon di- 10
oxide, and hexane was used as the eluent after trapping. The detailed
extraction conditions are shown in Table 1. The extraction liquid re-
covered by the fraction collector was diluted to 10 mL with hexane in
a measuring šask. The sample extraction vessel contained 7.4 mg of
d-α-tocopherol, and the theoretical concentration of d-α-tocopherol 0
in the ÿnal SFE extraction liquid was 0.74 mg/mL.
6. 0 7 .0 8.0 min
Fig. 6 Results for SFE Extraction Liquid Analyses
(The Six Samples Are Shown Overlapping Each Other).
The concentration and recovery of d-α-tocopherol in the six SFE ex-
traction liquid chromatograms (Fig. 6) are summarized in Table 3. The
Fig. 5 Sample Before and After the SFE Process extraction pretreatment showed both high repeatability and high re-
covery, thereby revealing that the Nexera UC SFE pretreatment
Table 1 SFE Conditions system can be used for the automated consecutive pretreatment of
target constituents in a solid sample with good efÿciency.
SFE
Extraction vessel : 5 mL
Table 3 Repeatability and Recovery of Vitamin E Extraction
Extraction solvent : CO2
Flow rate : 5 mL/min
Temperature : 40°C No. Conc. Recovery
Back pressure : 15 MPa (mg/mL) (%)
Extraction time : 15 min (Static extraction ĺ Dynamic extraction) 1 0.776 104.46
Trap & Pressure down conditions 2 0.780 105.00
Trap column : Shim-pack VP-ODS 4.6 mmI.D. × 50 mmL. 5 Žm 3 0.772 103.92
Temperature : 60°C 4 0.790 106.35
Pressure down time : 10 min (15–25 min)
5 0.761 102.44
Recovery conditions
6 0.758 102.04
Elution solvent : Hexane
Flow rate : 2 mL/min Average 0.773
Fraction time : 3.5 min (25–28.5 min) RSD (%) 1.549

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