COSMOSIL Index

COSMOSIL 3C18-EB

・ Excellent for Basic compounds
・ Improved separation for acidic or metal coordination compounds
・ Simple mobile phase conditions

Analysis of Basic Compounds

Conventionally end-capped C18 columns still have many residual silanol groups on the silica surface of stationary phase that can form ionic bonds with basic compounds. The resulting peak tailing makes accurate quantification of analytes difficult, especially in trace analyses. COSMOSIL 3C18-EB with a better end-capping treatment offers improved peak shape and separation particularly for basic compounds.

Comparison 1 (Basic Compounds)
COSMOSIL 3C18-EB Competitor A
C18, 3 µm		 Competitor B
C18, 3 µm		 Competitor C
C18, 3 µm
Comparison_EB Comparison_A Comparison_B Comparison_C
Condition
Column Size 4.6 mm I.D. x 75 mm
Mobile Phase Acetonitrile/ 20mmol/l Phosphate
Buffer(pH7.0) = 60/40
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 254 nm
Sample
1.  Amitriptyline 
2.　Propylbenzene (I.S.) 		0.2mg/ml
2.0mg/ml		 Amitriptyline
Inj. Vol 2.0 µl
Comparison 2 (Basic Compounds)
COSMOSIL 3C18-EB Competitor A
C18, 3 µm		 Competitor B
C18, 3 µm		 Competitor C
C18, 3 µm
Comparison2_eb Comparison2_a Comparison2_b Comparison2_c
Condition
Column Size 4.6 mm I.D. x 75 mm
Mobile Phase Acetonitrile/ 20mmol/l Phosphate
Buffer(pH7.0) = 60/40
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 234 nm
Sample
1. Dextromethorphan
2. Benzene (I.S.)		 0.5 mg/ml
7.5 mg/ml		 acidic_sample
Inj. Vol 1.5 µl

Analysis of Acidic or Metal Coordination Compounds

Acidic or metal coordination compounds can also form bonds with residual silanol groups and metal impurities causing peak tailing. COSMOSIL 3C18-EB with a better end-capping treatment and high purity silica gel offers improved peak shape and separation for acidic or metal coordination compounds.

Acidic Compounds
COSMOSIL 3C18-EB
application1
Condition
Column Size 4.6 mm I.D. x 75 mm
Mobile Phase Acetonitrile/ 20mmol/l Phosphate
Buffer(pH2.5) = 30/70
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV254 nm
Sample
1. Salicylic Acid
2. Ethyl p-Hydroxybenzoate (I.S.)		 1.0 mg/ml
0.05 mg/ml		 Salicylic Acid
Metal Coordination Compounds
COSMOSIL 3C18-EB
sample2
Condition
Column Size 4.6 mm I.D. x 75 mm
Mobile Phase Acetonitrile/ 20mmol/l
Phosphoric Acid = 10/90
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 254 nm
Sample
1. Oxine-copper
2. Caffeine (I.S.)		 0.03 mg/ml
0.3 mg/ml		 Oxine-copper
Inj. Vol 2.0 µl

Synthesis Reproducibility

If you use insufficiently end-capped C18 columns for basic compound analyses, you may need to spend much time adjusting mobile phase conditions. You may need

  1. more than 3 or more organic solvents or buffers
  2. ion-pair reagents or additives
  3. buffers in different pH


In addition, the complexity of the mobile phase often is detrimental to reproducibility. COSMOSIL 3C18-EB with a new end-capping treatment allows good peak shape and separation using simple mobile phase conditions.

Analysis with Simple Condition
Complicated Condition Simple Condition
Methanol/ Acetonitrile/ 20mmol/l KH2PO4, 0.2%Triethylamine(pH3.0 with H3PO4) = 35/15/50(*) Acetonitrile/ 20mmol/l Phosphate Buffer(pH2.5) = 30/70
Synthesis Reproducibility
(*): USP 38(1) Amlodipine and Benazepril Hydrochloride Capsules, Performance Tests
Condition
Column Size 4.6 mm I.D. x 100 mm
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 237 nm
Sample
1. Amlodipine
2. Benazepril		 0.0077mg/ml
0.0225mg/ml
Inj. Vol 50 µl

Routine Analysis

3C18-EB has excellent synthesis reproducibility and column-to-column reproducibility, so it is applicable in routine analysis such as quality control of drugs.

Excellent Synthesis Reproducibility
COSMOSIL 3C18-EB
Reproducibility1
Condition
Column Size 4.6 mm I.D. x 150 mm
Mobile Phase Acetonitrile / H2O = 60/40
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 254 nm
Sample
1. Acetophenone
2. Methyl Benzoate
3. Benzene
4. Toluene		 0.05 mg/ml
0.5 mg/ml
2.0 mg/ml
2.0 mg/ml
Inj. Vol 1.5 µl
COSMOSIL 3C18-EB
Reproducibility2
Condition
Column Size 4.6 mm I.D. x 150 mm
Mobile Phase Acetonitrile/ 20mmol/l Phosphate
Buffer(pH7.0) = 60/40
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 254 nm
Sample
1. Amitriptyline
2. Propylbenzene (I.S.)		 0.2 mg/ml
2.0 mg/ml
Inj. Vol 2.0 µl

Analysis under Ammonium Acetate Buffer

COSMOSIL 3C18-EB produces sharp peaks using ammonium acetate buffer in LC-MS.

Acetonitrile/ 20mmol/l Phosphate buffer(pH7.0) = 60/40 Acetonitrile/ 10mmol/l CH3COONH4 = 60/40
LC-MS1 LC-MS2
Condition
Column Size 4.6 mm I.D. x 75 mm
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV 254 nm
Sample
1.  Amitriptyline 
2.　Propylbenzene (I.S.) 		0.2mg/ml
2.0mg/ml		 Amitriptyline
Inj. Vol 1.0 µl

Analysis of standards in USP

COSMOSIL 3C18-EB
USP_app
Condition
Column Size 4.6 mm I.D. x 100 mm
Mobile Phase A; Acetonitrile/ 36.7mmol/l Phosphate Buffer(pH7.6) = 10/90
B; Acetonitrile/ 36.7mmol/l Phosphate Buffer(pH7.6) = 80/20
B conc. 0→ 20%(0→ 10min), 20→ 100%(10→ 30min)
Flow Rate 1.0 ml/min
Temperature 40°C
Detection UV302 nm
Sample
1. Omeprazole related compound A
2. Omeprazole		 0.001mg/ml
0.001mg/ml
Inj. Vol: 20 µl
USP 37(3) Esomeprazole Magnesium Delayed-Release Capsules, Impurities

Ordering Information

Product Name Size Product No.
COSMOSIL 3C18-EB Guard Column 4.6 mm I.D. x 10 mm 09839-41
COSMOSIL 3C18-EB Packed Column 2.0 mm I.D. x 50 mm 09794-21
2.0 mm I.D. x 75 mm 09795-11
2.0 mm I.D. x 100 mm 09796-01
2.0 mm I.D. x 150 mm 09797-91
2.0 mm I.D. x 250 mm 09798-81
3.0 mm I.D. x 50 mm 09799-71
3.0 mm I.D. x 75 mm 09800-21
3.0 mm I.D. x 100 mm 09811-81
3.0 mm I.D. x 150 mm 09814-51
3.0 mm I.D. x 250 mm 09827-91
4.6 mm I.D. x 50 mm 09840-01
4.6 mm I.D. x 75 mm 09841-91
4.6 mm I.D. x 100 mm 09842-81
4.6 mm I.D. x 150 mm 09843-71
4.6 mm I.D. x 250 mm 09844-61

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