An Inexpensive Alternative to Commercial Microbore HPLC Fittings Microbare HPLC is papular for the separation of components in small amounts of sample. Beginners to the technique are often warned of the fragility of small-0.d. microbore tuhing, a s are the users of certain commercial detectors that incorporate flowcells with a permanently mounted micro inlet tube. Breakages easily occur when components are changed, and leaks from finger-tight or stainless steel 1 1 6 ' PTFE TJBNG LSEDASShEAMlhG compression fittings are common. FOR CAPILARY M CROBORE T-B hG Although commercially available capillary tube liners are available for less than $10, chromatographers can improvise, using ordinary 0.063-in.-0.d. HPLC fittings. Stainless steel microhore capillary tubing may be easily threadedthrough0.031-in.-i.d.,0.063-in.-0.d. HPLCPTFE tubing, allowing the required length of capillary tubing to ZERO DEAD VOLUME protrude. The sheathed capillary tubing may then be treated as regular 0.063-in.-ad. HPLC tubing. (See the figure.) Not only is 0.063-in.-0.d. tubing easier to handle, \ ZERO DEADVOLUME but the capillary tubing is fully protected. f S.S. FERRULE To further w a r d against damage, the sheathed tubing CAPILLARY may be perrn&ently &pled to a zero dead-volume unioi, MkxzafE the opposite end ofwhich should be used for disassembly. TUBING Provided that the sheathed tubine is carefullv " cou~led . to zero dead-volume components, column resolution is not ZERO DEAD VOLUME compromised. UNION AND FITFINGS
Michael N. Quigley 1116" PTFE OR S.S. TUBING
Chevron Science Center University of Pittsburgh, Pinsburgh, P A 15260
Volume 68
Number 7
July 1991
599
