Exmere

    Alternative-selectivity C18

    Exsil Diametric C18

    Diametrically different selectivity – the optimum back-up phase when a standard C18 fails.

    100 Å210 m²/g1.5 – 10 µmType B
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    Exsil Diametric C18

    Same phase, two names – Exsil Diametric C18 is identical to Exsil Plus C18 EPS. Order under either name.

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    Pore size

    100 Å

    Surface area

    210 m²/g

    Pore volume

    0.52 mL/g

    Particle sizes

    1.5 – 10 µm

    Silica type

    Type B

    Phase

    C18 EPS

    What is Exsil Diametric C18

    Exsil Diametric C18

    Most modern C18 phases share high phase loading and extensive endcapping, which makes them highly hydrophobic and low in silanophilic activity. Exsil Diametric C18 has a diametrically opposite hydrophobic/silanophilic balance, which maximises the chance of improving resolution when a conventional C18 fails.

    Exsil Diametric C18 is the Exsil Plus C18 EPS phase: an uncapped C18 with extended polar selectivity on 100 Å Type B Exsil Plus silica.

    Why Exsil Diametric C18

    Why chromatographers choose Exsil Diametric C18.

    Diametrically different selectivity

    Opposite hydrophobic/silanophilic balance to standard C18.

    Higher retention of bases

    Higher base retention allows more organic in the eluent for better MS sensitivity.

    Water wettable and MS compatible

    High-polarity reversed phase.

    Excellent peak shapes

    Good peak shape maintained with volatile buffers at pH 7.

    Typical applications

    Where Exsil Diametric C18 is used.

    Wide-polarity mixtures

    Analysis time cut from 9 to 2 min for N,N′-diethylacetamide, 5-phenylpentanol and ethylbenzene.

    Pirimicarb and degradants

    Better resolution of the first pair with a shorter run.

    Nicotine in tobacco leaf

    Nicotine is retained and elutes after the solvent front.

    Bases at pH 7

    Amitriptyline retention × 4; doxepin isomers resolved with a volatile buffer.

    Performance evidence

    Performance evidence

    Snyder/Dolan hydrophobic-subtraction parameters

    Retention of Snyder solutes: two conventional C18 correlate with R² = 0.9994; Exsil Diametric C18 vs. conventional C18 only R² = 0.4347.

    PhaseHSABC (pH 2.8)C (pH 7)k′ PhEt
    Conventional C18 'A'0.99–0.060.1700.180.186.4
    Conventional C18 'B'1.000.01–0.095–0.0060.1430.0967.9
    Exsil Diametric C180.510.160.340.030.671.51.3

    Technical characteristics

    Engineered properties.

    Particle sizes1.5, 3, 5, 10 µm
    Pore size100 Å
    Specific surface area210 m²/g
    Pore volume0.52 mL/g
    Silica typeType B
    Base silicaExsil Plus 100
    Carbon loadAvailable on request
    MorphologyAvailable on request

    Available modifications

    Bonded phases on Exsil Diametric C18.

    Reversed phase

    • C18 EPS · L1
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    Sizes & formats

    Sizes & formats

    Particle sizeScale
    1.5 µmUHPLC – fast analytical
    3 µmHigh-throughput analytical
    5 µmRoutine HPLC / QC
    10 µmPreparative

    FAQ

    Frequently asked questions.

    Next step

    Exsil Diametric C18 enquiry

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