DESIGN OF A HIGH-PRECISION FRACTION COLLECTOR FOR CAPILLARY ELECTROPHORESIS

high-precision fraction collector for capillary electrophoresis has be en developed. The device utilizes detection close to the end of the ca pillary and a sheath liquid at the exit of the capillary, allowing con tinuous collection (i.e., uninterrupted applied electrical field) of m ultiple species, The role of the sheath liquid now rate and position o f detection in the column on the collection precision was assessed. Fi ber-optic detection at similar to 1 cm before the exit end of the capi llary was found effective for precise timing of the collection. Up to 60 fractions of microliter or smaller volumes could be automatically c ollected into capillaries used as collection vials. The collection cap illaries were placed on a cylinder, and a computer-controlled stepping motor aligned the appropriate capillary with the column exit. The eff ectiveness of the fraction collector was demonstrated in the collectio n of all 11 fragments of the HaeIII restriction digest of Phi X-174 pl asmid DNA. Polymerase chain reaction amplification of the 271 and 281 bp fragments revealed an inversion of the size-dependent migration ord er.