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Handbook of Size Exclusion Chromatography and Related ...

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chains in their swollen state. They were found to be much less susceptible to<br />

secondary interaction effects than silica-based packings so that separations<br />

dominated by size exclusion were readily achieved. However, the disadvantage<br />

was that the highly swollen, microporous networks had poor mechanical strength<br />

<strong>and</strong> were therefore not really suitable for high-performance SEC performed with<br />

relatively short, low capacity columns at high eluent flow rates.<br />

PackingsforhighperformanceaqueousSEChavethereforebeendeveloped<br />

(25,26)whicharerigid,whichhavefunctionalitiessimilartothose<strong>of</strong>thes<strong>of</strong>tgels,<br />

<strong>and</strong> which can tolerate awide range <strong>of</strong> pH. Table 3summarizes the range <strong>of</strong><br />

commercial high-performance aqueous SEC packings available, while more<br />

comprehensive information is documented elsewhere (6).<br />

Many<strong>of</strong>thecommentsreferredtoinSecs.3.2–3.5applyequallytoaqueous<br />

SEC. The remainder <strong>of</strong> this section will discuss other important parameters<br />

specific to semirigid polymeric packings for aqueous SEC.<br />

4.2 Porosity<br />

Poresizedistributionisexpressedintheform<strong>of</strong>anSECcalibrationplot,logMvs.<br />

elution volume, but whereas for organic SEC polystyrene st<strong>and</strong>ards are used<br />

almost exclusively,for aqueous SEC packings resolving ranges are commonly<br />

quoted in terms <strong>of</strong> polyethylene oxide/glycol (PEO/PEG), polysaccharides, or<br />

Table 3 Commercial Column Packing Materials for Aqueous SEC<br />

Type Chemistry Pore size range<br />

PL aquagel–OH Macroporous<br />

with OH<br />

functionality<br />

Shodex OHpak Hydroxylated<br />

PMMA<br />

TSK-GEL PW Hydroxylated<br />

PMMA<br />

Ultrahydrogel Hydroxylated<br />

PMMA<br />

Particle size<br />

range (mm) Supplier*<br />

AOH30–AOH60 þMIXED 8–15 1<br />

SB802HQ–SB806HQ þ<br />

MIXED<br />

8–13 2<br />

G1000–G6000 þMIXED 6–25 3<br />

120 A ˚ –2000 A ˚ 4<br />

PSS HEMA Acrylic 40 A ˚ –1000 A ˚ þMIXED 10 5<br />

PSS Suprema OH-acrylic 30 A ˚ –30,000A ˚ þMIXED 5–20 5<br />

*1: Polymer Laboratories (www.polymerlabs.com)<br />

2: Shodex (www.sdk.co.jp/shodex)<br />

3: Tosoh (www.tosohbiosep.com)<br />

4: Waters Corporation (www.waters.com)<br />

5: Polymer St<strong>and</strong>ards Service (www.polymer.de)<br />

© 2004 by Marcel Dekker, Inc.

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