INTRINSIC ISOTACHOPHORETIC PRECONCENTRATION IN CAPILLARY GEL-ELECTROPHORESIS OF DNA RESTRICTION FRAGMENTS

Reproducible migration times are required for accurate base-pair assignment of polymerase chain reaction (PCR) products in capillary gel electrophoresis (CGE). However, migration times are influenced by injection plug length and ionic strength of the sample. In this paper we introduce a new isotachophoresis (ITP)-CGE system where the transition from ITP to CGE is achieved by the mobility shift of DNA from free solution (ITP) to sieving gel buffer (CGE). With intrinsic isotachophoretic preconcentration in capillary gel electrophoresis (IICGE) large volume injections (up to 700 nl) are possible with accurate migration times in CGE independent of injection plug length or sample ionic strength.