Poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) for high resolution and high speed separation of DNA by capillary electrophoresis

A new separation medium, poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) (PNIPAM-g-PEO) solution, used for double-stranded (ds) DNA separation by ca pillary electrophoresis (CE) is presented. This type of grafted copolymer h as a good self-coating ability for quartz capillary tubing and a slightly t emperature-dependent viscosity-adjustable property, making it easier to use . One bp resolution was achieved within 12.5 min by using 8% w/v PNIPAM-gPE O in 1 x TEE (Tris-borate-ethylenediaminetetraaceticacid) buffer with an ef fective column length of 10 cm and an applied electric field strength of 20 0 V/cm. The PNIPAM-g-PEO solutions had a high sieving ability for relativel y small sized DNAs with the relative standard derivation for the first 10 r uns being less than 0.9% by using the same polymer solution. With 8% w/v PN IPAM-g-PEO solution in a 1.5 cm column and 2400 V as the running voltage, P hi 174/Haelll digest could be clearly separated within 24 s.