Page 87 - Application Handbook - Liquid Chromatography

LAAN-A-LC-E271

Application Supercritical Fluid Chromatography

News Automated Optimization of Chiral Separation

Parameters Using Nexera UC Chiral Screening System
No.L495

Chiral compounds contain asymmetric carbons in their n Separation Parameters for the Chiral Screening System
molecules and are not superimposable on their mirror Model sample: The structure of omeprazole is shown
images. HPLC has been the main method used to in Fig. 1. Daicel CHIRALPAK /CHIRALCEL series 12
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separate such chiral compounds, but in recent years, the columns for chiral analysis were used for the analysis.
use of supercritical fluid chromatography (SFC) has been These columns offer a line of complementary stationary
gaining attention. The main mobile phase used for chiral phase columns that are able to separate a wide variety
SFC is supercritical carbon dioxide, with low polarity, of chiral compounds. When used in combination with
low viscosity, and high diffusivity, to which polar organic the Nexera UC chiral screening system, which features
solvents (modifiers) are added to control solubility and a method scouting function, optimal chiral separation
polarity. Therefore, chiral compound separation by parameters can be determined easily. In addition, three
HPLC, which generally uses normal phase conditions, types of modifiers were used, methanol, ethanol, and
offers the potential for high speed, low organic solvent a mixture of acetonitrile and ethanol. Details about the
consumption, low cost, and low environmental impact. separation parameters are indicated in Table 1. The optimal
However, chiral SFC requires selecting a variety of parameters for chiral separation were comprehensively
separation parameters, such as columns and modifiers, selected from the total of 36 possible combinations of
which can involve large amounts of time and effort. This modifiers (3 types) and columns (12 types).
article describes using the Nexera UC chiral screening
system to automatically optimize the large number of
separation parameters by switching between up to 12
columns and various mixture ratios of four types of
modifiers. This can significantly reduce the effort required.
Table 1 Analytical Conditions
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Column : CHIRALPAK , CHIRALCEL Series
100 mm L. × 3.0 mm I.D., 3 μm
Mobile Phase : A; Super critical fluid of CO2
B; Modifier: Methanol, Ethanol, mixture of
Acetonitrile: Ethanol = 3:1 (v:v)
Time Program : B Conc. 20 % (0 - 8 min) → 40 % (8 - 10 min)
→ 20 % (10 - 14 min)
Flowrate : 3 mL/min
Column Temp. : 40 °C
Omeprazole Injection Volume : 2 μL
BPR Pressure : 10 Mpa
Fig. 1 Sample Used to Evaluate the Method Scouting Function Detector : Photodiode Array Detector (Max Plot 210 - 400 nm)

Fig. 2 Method Scouting Solution Operating Screen for Nexera UC