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Handbook of Size Exclusion Chromatography and Related ...

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Figure 14 Reproducibility <strong>of</strong> broad polystyrene (four repeats) analyzed on ashort SEC<br />

column using an optimized instrument with an analysis time <strong>of</strong> 7.5 min (Rick Nielson,<br />

private communication).<br />

SEC st<strong>and</strong>ards (DIN 55672 in Germany). Equilibration time for an instrument<br />

prior to calibration is about 10 hours (overnight).<br />

The total calibration time using conventional columns is about: 600 min<br />

(prep time) þ10 60 min (st<strong>and</strong>ards run time) ¼1200 min ¼20 hours (that is,<br />

about 2.5 workdays).<br />

Running aHighSpeed SEC system 10 times faster than aconventional one<br />

will reduce total calibration time accordingly: 60 min (prep time) þ10 6min<br />

(st<strong>and</strong>ards run time) ¼120 min ¼2hours (that is, about aquarter <strong>of</strong> aworkday).<br />

Analysis time for checkout samples <strong>and</strong> unknowns is the same. Assuming<br />

that 10 samples are run in asequence on aconventional system, the total analysis<br />

time is 10 60 min ¼600 min (more than an average workday). Whereas on a<br />

HighSpeed system only 60 min will be required (less than 15% <strong>of</strong> atypical<br />

workday).<br />

This means that in our scenario equilibration, calibration, validation, <strong>and</strong><br />

unknown sample analysis can be done on the same day in the HighSpeed case;<br />

there is even room for more samples or other work on that day. However,<br />

aconventional system will require about two days <strong>and</strong> anight (for equilibration),<br />

tying up substantial manpower <strong>and</strong> instrument time.<br />

Figure 15 shows apractical calibration example from work done by the<br />

author using only asingle conventional column (run time 15 min per sample)<br />

© 2004 by Marcel Dekker, Inc.

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