Products

COSMOSIL 1.8C18-MS-II

  • Well-balanced selectivity for general-purpose separations
  • Stable lot-to-lot quality and superior separation

Fast analysis by UHPLC

Ultra-high performance liquid chromatography (UHPLC) is a technology for speeding up analysis by using columns packed with smaller silica gel particles than standard HPLC and flowing mobile phase at a high rate. Analyses by UHPLC are increasing in number every year, and it is sure to continue to be an important technology in years to come.

chart of references for uhplc

Our UHPLC columns include COSMOSIL 1.8C18-MS-II, made with fully porous silica, and COSMOCORE 2.6C18, made with core-shell silica. Users should choose the appropriate column based on their instrument and analysis requirements.

Fully porous silica
(COSMOSIL 1.8C18-MS-II)

Core-shell silica
(COSMOCORE 2.6C18)
Pore size: about 12 nm
Specific surface area: about 340 m2/g
Max. pressure: 80 MPa
Usable pH range: 2‒10* fully porous silica		 Pore size: about 9 nm
Specific surface area: about 150 m2/g
Max. pressure: 60 MPa
Usable pH range: 2‒10* core-shell silica
Because the fully porous silica has pores throughout its structure, it can interact with the sample over a very wide surface area. As the amount of octadecyl phase that can be bonded increases, hydrophobic samples can be retained longer, leading to improved separation. With core-shell silica’s nonporous core, sample dispersion is reduced; compared to fully porous columns, high theoretical plate numbers can be achieved even with larger particles. These larger particles result in lower backpressure, enabling use on conventional HPLC instruments.

* Silica gel columns are generally recommended to be used within pH 2–7.5. Outside this range, column degradation may happen more quickly.

Comparison of fully porous and core-shell columns

UHPLC columns exhibit very high numbers of theoretical plates, so good separation can be achieved even on short columns.

Retention of alkylbenzenes

chromatogram of various alkylbenzenes

Conditions
Column size 2.1 mm I.D. × 50 mm
Sample
  1. Benzene (n=0)
  2. Toluene (n=1)
  3. Ethylbenzene (n=2)
  4. Propylbenzene (n=3)
  5. Butylbenzene (n=4)
  6. Amylbenzene (n=5)

structure of sample
Mobile phase Acetonitrile / H2O = 60 / 40
Flow rate 0.4 mL/min
Temperature 40°C
Detection UV 254 nm

Separation of structural isomers of vitamin D

COSMOSIL 1.8C18-MS-II has strong retention and selectivity for hydrophobic compounds, so it can separate these structural isomers of vitamin D. The C18-MS-II series has particle sizes of 1.8, 2.5, 3, 5, and 15 µm available, so scaling up to preparative separation is a smooth process.

chromatogram of isomers of vitamin D

Conditions
Column size 2.1 mm I.D. × 50 mm Temperature 40°C
Mobile phase Methanol / H2O = 90 / 10 Detection UV 265 nm
Flow rate 0.4 mL/min
Sample

This sample was prepared by mixing the below in a 1:3 ratio:

  • 0.25 mg/mL vitamin D3 in methanol
  • 0.25 mg/mL 7-DHC in methanol, exposed to 254 nm UV light for 30 min.
  1. Previtamin D3
  2. Vitamin D3
  3. Lumisterol
  4. 7-Dehydrocholesterol (7-DHC)

vitamin D sample

Comparison to competitor columns

COSMOSIL 1.8C18-MS-II and COSMOCORE 2.6C18 were compared to a competitor UHPLC column. COSMOSIL 1.8C18-MS-II, with its high retention for hydrophobic compounds, is able to separate compounds that the competitor column was not able to separate. COSMOCORE 2.6C18 is similar in retention and selectivity to the competitor column, but ran with less than half the backpressure.

Drug analysis (NSAIDs)

COSMOSIL 1.8C18-MS-II, with its high hydrophobicity and selectivity, was able to separate difficult compounds.

chromatogram of NSAID drugs

Conditions
Column size 2.1 mm I.D. × 50 mm Flow rate 0.4 mL/min
Mobile phase Methanol / 0.1% HCOOH aq. = 60 / 40 Temperature 40°C
Detection UV 260 nm
Sample
  1. Acetylsalicylic Acid
  2. Loxoprofen
  3. Ketoprofen
  4. Naproxen
  5. Phenylbutazone
  6. Celecoxib
  7. Diclofenac
  8. Indometacin
 NSAID samples

Flavonoid analysis

Compared to isocratic elution, in this gradient elution, the differences in retention time between the columns was small, and elution order was the same. However, COSMOSIL 1.8C18-MS-II and COSMOCORE 2.6C18 were still able to separate compounds that were not separated on the competitor column.

chromatogram of various flavonoids

Conditions
Column size 2.1 mm I.D. × 50 mm Flow rate 0.4 mL/min
Mobile phase

A : 0.1% formic acid in water
B : 0.1% formic acid in acetonitrile
B conc. 10 → 70% 10 min. linear gradient

 Temperature 40°C
Detection UV 280 nm
Inj. vol. 1.0 µL
Sample

flavonoid samples

Durability of UHPLC columns

UHPLC columns are routinely exposed to high pressures. To evaluate the durability of these columns, amitriptyline was injected 1,000 times into each column. Neither COSMOSIL 1.8C18-MS-II nor COSMOCORE 2.6C18 saw deterioration in retention time or peak shape (width at half height).

COSMOSIL 1.8C18-MS-II

COSMOCORE 2.6C18
durability chart for fully porous column durability chart for core-shell column
Conditions
Column size 2.1 mm I.D. × 50 mm Flow rate 0.4 mL/min
Mobile phase A: 0.1% TFA in water
B: 0.1% TFA in acetonitrile
B conc. 5 → 90% (0.00 - 3.00 min), 90 → 5% (3.00 - 3.01 min.), 5% (3.01 – 6.00 min.)		 Temperature 40°C
Detection UV 236 nm
Sample Amitriptyline (0.2 mg/mL)
Inj. vol. 1.0 µL

Note on connector type

Our UHPLC columns use the same connectors as Waters UPLC® (UHPLC) columns. This is different from our conventional COSMOSIL columns, which use the conventional Waters HPLC-compatible connectors. Attempting to connect an unsuitable fitting may result in it becoming stuck in the column.

connector diagram

Ordering information

COSMOSIL 1.8C18-MS-II Analytical Columns (particle size: 1.8 µm)

Product name Size Product no. Price
COSMOSIL 1.8C18-MS-II Packed Column
2.1 mm I.D. x 30 mm 22132-71 e-Nacalai
2.1 mm I.D. x 50 mm 22136-31
2.1 mm I.D. x 75 mm 22137-21
2.1 mm I.D. x 100 mm 22138-11
2.1 mm I.D. x 150 mm 22139-01