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 wh ich forms part of the conductivity cell. Ability to splice different c apillaries to the sensor would allow versatility in choice of capillar y dimensions and bonded columns as well as simply replacing old capill aries. 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 origina l commercial capillary of the same dimensions through electropherogram s of a mixture of anionic surfactants taken with a NaF buffer. The pla te count (N) and resolution (R-s) of the spliced capillary averaged 93 % and 82% of those for the unspliced capillary. The, reproducibility o f 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. Cha racterization with respect to N and R-s of capillaries with different diameter and lengths for CE of anionic surfactants with conductivity d etection is also investigated. An amine bonded capillary permitted the separation of anions or cations using the same electrolyte but just s witching the polarity of the applied voltage. (C) 1998 Elsevier Scienc e B.V. All rights reserved.