Applications for Achiral Compound Separations (Comparison by bar graph)

Below are examples demonstrating the separation of the structural isomers of various derivatized compounds. These were analyzed by both an ODS-type column as well as several polysaccharide-based chiral stationary phases (CSPs) including CHIRALCEL® OB-H, OJ-H, OD-H, and CHIRALPAK® AD-H. The difference in retention time of each isomer is shown using a bar graph. For the ODS-type column, the elution order of the ortho-, meta-, and para-substituted isomers was found to be ortho- first, then meta-, and lastly para-. Conversely, the elution order of the isomers was found to differ depending on the type of CSP used. It's important to note that these separations are also feasible using our solvent-resistant chiral columns (iCHIRAL series). Some separation data for these iCHIRAL columns is also shown below.

Separation of biphenyl and methylbiphenyl by OJ-H

Separation of the three isomers of biphenyl and methylbiphenyl by ODS and OJ-H

Column:
0.46cmφ x 25cm
Mobile Phase:
MeCN / Water = 70 / 30 (v/v)
Flow rate:
1.0mL/min
Column:
OJ-H 0.46cmφ x 25cm
Mobile Phase:
n-Hex / IPA = 99 / 1 (v/v)
Flow rate:
1.0mL/min
Separation of the three isomers of biphenyl and methylbiphenyl by ODS and OJ-H

Polysaccharide-based CSPs are effective not only for optical isomer separations (enantiomeric separations), but also for achiral separations such as for diastereomers or structural isomers. The above chromatograms show the separation of biphenyl and three methylbiphenyl derivatives by an ODS-type column and CHIRALCEL® OJ-H. For the ODS-type column, the introduction of a methyl group enhances retention of all isomers. This change is based on well-known physicochemical rules i.e. the increase in hydrophobicity by the presence of the methyl group. Despite this increased retention, there is low selectivity of the three methyl isomers. However, for CHIRALCEL® OJ-H, there is quantitative separation of all four isomers. The ortho- isomer is weakly retained and elutes first, followed by the unsubstituted biphenyl, then the meta- isomer, and lastly the para- isomer. This is a result of the major difference in the separation mechanism: the ODS-type column distinguishes between the physicochemical properties of molecules, namely hydrophobicity in this case. The polysaccharide-based CSP uses the unique shape of individual molecules, resulting in better recognition.

The below bar graphs represent the retention times of the structural isomers for a series of biphenyl derivatives, as well as of the structural isomers for a series of benzyl ketone derivatives. These compounds were analyzed using an ODS-type column and several polysaccharide-based CSPs, including CHIRALCEL® OB-H, OJ-H, OD-H, and CHIRALPAK® AD-H. For the ODS-type column, the elution order of the ortho-, meta-, and para-substituted isomers was found to be ortho- first, then meta-, and lastly para-. Conversely, the elution order of the isomers was found to differ depending on the type of CSP used.

Dimethylbiphenyl

Dimethylbiphenyl
Dimethylbiphenyl

Terphenyl

Terphenyl
Terphenyl

Methylacetophenone

Methylacetophenone
Methylacetophenone

Bromoacetophenone

Bromoacetophenone
Bromoacetophenone

Phenylphenol

Phenylphenol
Phenylphenol

Phenylacetate

Phenylacetate
Phenylacetate

Methylbenzophenone

Methylbenzophenone
Methylbenzophenone

Separation of polycyclic aromatic compounds

Separation of polycyclic aromatic compounds
Separation of polycyclic aromatic compounds

Separating Achiral Compounds by Solvent-Resistant Chiral Columns (iCHIRAL Series)

Coumarin and dihydrocoumarin isomers

Coumarin
Column:
ODS
Mobile Phase:
MeCN / Water = 60 / 40 (v/v)
Flow rate:
1.0mL/min
Column:
Chiral columns of polysaccharide derivatives
Mobile Phase:
n-Hex / IPA = 90 / 10 (v/v)
Flow rate:
1.0mL/min
Coumarin and dihydrocoumarin isomers
Column:
CHIRALPAK® IC
Modifier
MeOH 3%
Flow rate:
1.0mL/min
Coumarin and dihydrocoumarin isomers

Dimethyl phthalate

Dimethyl phthalate
Column:
ODS
Mobile Phase:
MeCN / Water = 70 / 30 (v/v)
Flow rate:
1.0mL/min
Column:
Chiral columns of polysaccharide derivatives
Mobile Phase:
n-Hex / IPA = 90 / 10 (v/v)
Flow rate:
1.0mL/min
Dimethyl phthalate

Diphenyl phthalate

Diphenyl phthalate
Column:
ODS
Mobile Phase:
MeCN / Water = 70 / 30 (v/v)
Flow rate:
1.0mL/min
Column:
Chiral columns of polysaccharide derivatives
Mobile Phase:
n-Hex / IPA = 100 / 1 (v/v)
Flow rate:
1.0mL/min
Diphenyl phthalate

※Abbreviations in the page

Column name Abbreviations in the page
CHIRALCEL® OB-H OB-H
CHIRALCEL® OJ-H OJ-H
CHIRALCEL® OD-H OD-H
CHIRALPAK® AD-H AD-H
CHIRALPAK® IA IA
CHIRALPAK® IB N-5 IB N
CHIRALPAK® IC IC
CHIRALPAK® IG IG

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