Capcell Pak C18 AQ | HPLC Column | Particle Size 3μm

Inner Diameter (mm): 4.6 mm
Length (mm): 150 mm
Sale price$608.00 USD


The Capcell Pak C18 AQ is a high-polarity C18 column with durability that has been improved using Osaka Soda's original polymer coating technology. In addition to the stability in 100% aqueous mobile phase, the polymer coating minimizes the influence of residual silanol groups and provides good peak shape for basic compounds.

Stable reproducibility with 100% aqueous mobile phase

Although retention can be increased by lowering the rate of organic solvent in the mobile phase with the C18 column, reproducibility cannot be realized with 100% aqueous mobile phase.

CAPCELL PAK C18 AQ addresses this by assuring good reproducibility even with 100% aquatic moble phase by optimizing the introduction of octadecyl group and polymer coating of the base packing material with a novel polymer.


  • The highest surface polarity among C18 columns

With the highest surface polarity among C18columns, the AQ type enables strong retention and high separation of high polarity compounds. Furthermore, it enables the use of 100% aqueous mobile phase, which used to present problems in reproducibility with the conventional ODS columns.

Additionally, since it is coated with a polymer, the peak profile of basic compounds is free from tailings and, consequently, extremely good.

Hydrophobicity and surface polarity parameters of Osaka Soda columns

  • Excellent retention capacity for high polarity compounds

Designed for high surface polarity, CAPCELL PAK C18 AQ is the only column among CAPSELL PAK products that enables stable analysis with 100% aqueous mobile phase. Moreover, it has excellent retention capacity for high polarity compounds.

Fig. 1 Analysis of nucleic-acid bases

4.6mm i.d.×150mm
Mobile phase:
20mmol/L KH2PO4
20mmol/L K2HPO4
Flow rate: 1.0mL/min
Temperature: 40°C
Detection: UV254nm
Sample:(1) Sodium sulfite (2) Cytosine (3) Thymine (4) Uracil (5) Adenine (6)Guanine

Fig. 2 Analysis of water soluble vitamin B group

4.6mm i.d.×75mm
Mobile phase: 10mmol/L CH3COONH4
Temperature: 40°C
Flow rate: 1.0mL/min
Detection: UV254nm
Sample: (1) Nicotinic acid
(2) Pyridoxal
(3) Pyridoxine
(4) Nicotinamide
(Concentration is 100μL/mL for all)
Injection volume: 10μL

  • Higher-than-expected separation capacity even with 100% organic solvent mobile phase

 Since the type of polymer coating and the introduction rate of C18 have been modified to enable the use of 100% aqueous mobile phase, hydrophobic compounds can be eluted faster with 100% organic mobile phase.

Fig. 3 Analysis of lipid soluble vitamins

  • High resistance to acid and alkali

Poor durability is a problem in columns designed for use with 100% aqueous mobile phase. However, the AQ has been designed to improve resistance to acid and alkali with a polymer coating and the introduction of a unique C18 group.

AQ shows excellent resistance to acid and alkali in comparison with other columns capable of using 100% aqueous mobile phase, in which the resistance tends to deteriorate quickly.

Fig. 4 Results of durability test

Test conditions for acid resistance
Mobile phase:
(A)2vol% TFA,H2O(pH1)
(B)2vol% TFA,CH3CN
B 65% (20min) → 0% (60min)
→ 98% (5min) → 65% (5min)
Flow rate:
Uracil, amyl benzene
Test conditions for alkali resistance
4.6mm i.d.×150mm
Mobile phase:
4mmol/L Na2B4O7/CH3OH
=90/10 (pH10.0)
Flow rate:
* Survival rate (%) of retention factor (k) of benzyl alcohol after 20 hours of dipping
    • Good peak profile also with basic compounds

    The AQ type column comprises packing material coated with polymer; least influenced by silanol, and, consequently, is able to elute the basic compounds as a sharp peak without tailing.

    Fig. 5 Analysis of pyridine/phenol

    Column: 4.6mm i.d.×150mm
    Mobile phase: CH3CN/H2O=30/70
    Flow rate: 1.0mL/min
    Temperature: 40°C
    Detection: UV254nm
    Sample: (1) Pyridine (2) Phenol
    As: Tailing factor

        • Realization of low pressure allows a length of 250 mm and a particle diameter of 3 µm

        Through the selection of silica gel accurately graded for AQ, high number theory plate (NTP) in 5 and 3 µm particle with an amazingly low pressure became available.

        The changeover from a particle of 5 µm to 3 µm has enabled improved separation and fast analysis. Which option would you prefer to pursue in the analysis of high polarity compounds?


        Fig. 6 Column pressure  
        Conditions for comparison of column pressure
        Column size: 4.6mm i.d.×150mm
        Mobile phase: H2O/CH3OH=50/50
        Flow rate: 1.0mL/min
        Temperature: 40°C

        Physical Properties


        surface area
        (m 2/g)
        C% Density
        (µmol/m 2)
        Range of
        applicable pH
        Octadecyl group 3 8 330 12 1.7 2~9 L1
        Octadecyl group 5 8 300 11 1.7 2~9 L1

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