Column Image

  • Nitrophenylethyl group bonded stationary phase
  • Separation with dipole-dipole and π-π interactions
  • Excellent separation for structural isomers

Product Information

Column Specifications

Column Specifications

Selectivity for Dipole-dipole Interactions

COSMOSIL NPE strongly retains 1,8-dinitronaphthalene because of the strong dipole formed by the two nitro groups positioned on the same side of naphthalene.


Column Size 4.6 mm I.D. x 150 mm structures
Mobile Phase 5NPE Methanol : Water = 70 : 30
5PYE Methanol : Water = 90 : 10
5C18-MS-II Methanol : Water = 80 : 20
Flow Rate 1.0 ml/min
Temperature 30°C
Detection UV 254 nm
  1. 1,8-Dinitronaphthalene 0.21 µg
  2. 1,5-Dinitronaphthalene 0.11 µg
  3. Naphthalene 0.25 µg
  4. 1-Methylnaphthalene 0.35 µg
  5. 1,5-Dimethylnaphthalene 0.42 µg


  1. Methanol is recommended as a mobile phase for COSMOSIL NPE column. Acetonitrile is not recommended because it has many π electrons and interferes π-π interactions between a sample and the stationary phase.
  2. The stationary phase of COSMOSIL NPE, nitrophenyl group, has a large UV absorption. When the stationary phase detaches from silica gel and elutes, even a slight quantity can be detected and causes baseline noise. In such a case, wash the column with tetrahydrofuran. Detachment of a small amount of the stationary phase does not deteriorate a column’s separation ability.
  3. COSMOSIL NPE column is not suitable for gradient analysis.


COSMOSIL Application Search

Usage information

Column 5 µm NPE
I.D. (mm) 2.0 3.0 4.6 10.0 20.0
Washing method 5 µm C18-MS-II
Storage conditions Short-term (up to a week):
Remove buffer, salts and/or acid from column: wash for 10-15 min. using the mobile phase last used, without buffer, salts or acid. For example, if your mobile phase was 50:50 methanol/20 mmol/l phosphate buffer, wash with 50:50 methanol/water.

Remove buffer, salts and/or acid from column: wash for 10-15 min. using the mobile phase last used, without buffer, salts or acid. Then, replace the solvent with 70% methanol or acetonitrile : 30% water.

In either case, tightly plug the column, and store in a cool and dry place.
Usable pH range pH2~pH7.5
Max. pressure 20MPa 15MPa
Temperature range The maximum usable temperature is 60°C. However. for regular use, please use at a constant temperature between 20°C and 50°C.
Usable solvents Any solvent that will not dissolve the silica gel (such as alkaline solutions) or cleave the stationary phase (such as very acidic solutions) is usable.
Note: For solvents with high viscosity, please watch the system pressure and keep it below 20 MPa. Also, please wash the column after using acidic mobile phases or solvents with high freezing points.
Other instructions - Buffer concentration is usually sufficient at 0.005 - 0.02 mol/L.
- Always filter mobile phases using a 0.5 µm or finer filter before use.
- As acetonitrile interferes with π electron interactions, please use a methanol-based mobile phase.
- The baseline may become unstable due to the high UV absorption of shedded stationary phase. If this occurs, please wash the column with THF. A small amount of stationary phase shedding will not affect performance.
- This column is not suitable for gradient analysis.




Reference list

Ordering Information

Analytical Column (Particle Size : 5 µm)

Product Name Size Product No. Price
COSMOSIL 5NPE Guard Column
4.6 mm I.D. x 10 mm 37904-01 e-Nacalai
10 mm I.D. x 20 mm 38045-31
20 mm I.D. x 20 mm 05868-81
20 mm I.D. x 50 mm 05869-71
COSMOSIL 5NPE Packed Column
1.0 mm I.D. x 150 mm 05897-01 e-Nacalai
2.0 mm I.D. x 150 mm 34328-51
2.0 mm I.D. x 250 mm 34379-91
4.6 mm I.D. x 150 mm 37902-21
4.6 mm I.D. x 250 mm 37990-71
10 mm I.D. x 250 mm 05469-11
20 mm I.D. x 250 mm 38046-21

(Storage) RT: Room temperature, A: Cool and dark, R: Refrigerator, F: Freeze