Spliced capillaries for use in capillary electrophoresis with conductivity detection

Presently, commercial capillaries for use in capillary electrophoresis (CE) with conductivity detection have a permanently mounted sensor which forms part of the conductivity cell. Ability to splice different capillaries to the sensor would allow versatility in choice of capillary dimensions and bonded columns as well as simply replacing old capillaries. Various capillaries can be easily joined to the sensor using a zero dead volume stainless steel union and ferrule. The performance of a 60 cm x 50 mu m spliced capillary is compared to that of an original commercial capillary of the same dimensions through electropherograms of a mixture of anionic surfactants taken with a NaF buffer. The plate count (N) and resolution (R-s) of the spliced capillary averaged 93% and 82% of those for the unspliced capillary. The, reproducibility of the peak height and peak mobility of the surfactants for the spliced capillary are generally 1-3% R.S.D. and <1% R.S.D., respectively. Characterization with respect to N and R-s of capillaries with different diameter and lengths for CE of anionic surfactants with conductivity detection is also investigated. An amine bonded capillary permitted the separation of anions or cations using the same electrolyte but just switching the polarity of the applied voltage. (C) 1998 Elsevier Science B.V. All rights reserved.