Using sleeves to connect capillary tubing into standard fluidic ports
Using tubing sleeves is a convenient and cost-efficient way to connect capillary dimension tubing into standard ports without introducing additional components or dead volumes. The sleeves ensure a fully concentric alignment while also being adaptable to many port depths and designs. In this way, 360 µm OD fused silica capillaries and other tubing of similar dimensions, can be connected to flat-bottom and coned ports with thread types of 10-32, 6-40, and 6-32, as well as to port designs compatible with Lee MINSTAC, and Valco Nanovolume.
Biotech Fluidics supply a range of different tubing sleeves to fit several fittings systems, including the IDEX MicroTight®, NanoTight™, SealTight™, TinyTight™, and Super Flangeless™ polymeric fittings, plus traditional stainless-steel fittings. These sleeves differ in their outer diameters and materials, and therefore have varying tolerances to temperatures and pressure. The table below summarizes the many options and their features, including what capillary dimensions the different types of tubing sleeves can accommodate, and what fittings would be compatible.
Using tubing sleeves is easy. First, select a sleeve material and outer diameter (OD) that match your fitting system and receiving port, and then find a sleeve inner diameter (ID) that match the OD of your capillary tubing while allowing 0.001”–0.002” (25–50 µm) gap between the capillary and the sleeve. Then, slip the sleeve over your capillary tubing, such that your capillary extends all the way through the sleeve, so their ends are flush. After that, insert the sleeved capillary into the fitting and let the sleeved tubing extending somewhat. Finally, place the fitting into the port, ensuring that the sleeved tubing assembly bottoms out prior to tightening the fitting. Note that for connections into true zero dead volume (ZDV) unions, a plug is required at the other end when inserting and tightening the first sleeved assembly, but not for the second.
To learn more about the IDEX tubing sleeves and their capabilities, visit their product pages linked below, or contact Biotech Fluidics for guidance.
| Sleeve OD | Type and Material | Fitting System and Port* | Capillary Tubing ODs | Pressure Limit** | Fitting Part No. |
|---|---|---|---|---|---|
| 0.025" | MicroTight® (PEEK) | MicroTight®, 6-32 C | 70–520 µm | 4,000 psi (276 bar) | F-125 |
| 0.025" | MicroTight® (PEEK) | MicroTight®, 5/16-24 C | 70–520 µm | 4,000 psi (276 bar) | F-172, P-416 |
| 1/16" | NanoTight™ (FEP) | NanoTight™, 10-32 C | 70 µm–1 mm | 4,000 psi (276 bar) | F-333N |
| 1/16" | NanoTight™ (FEP) | Super Flangeless™, 6-32 FB | 70 µm–1 mm | 750 psi (52 bar) | M-650, M-660 |
| 1/16" | NanoTight™ (FEP) | Super Flangeless™, 6-40 FB | 70 µm–1 mm | 750 psi (52 bar) | M-650, M-644-03 |
| 1/16" | NanoTight™ (FEP) | TinyTight™, 6-40 FB | 70 µm–1 mm | 600 psi (41 bar) | M-647, M-644-03 |
| 1/16" | NanoTight™ (FEP) | Lee MINSTAC® Alt, 6-40 FB | 70 µm–1 mm | 600 psi (41 bar) | M-647, M-644-03 |
| 1/16" | PEEK | SealTight™ (WT), 10-32 C | 175–770 µm | 6,000 psi (414 bar) | F-193 |
| 1/16" | PEEK | Stainless Steel (WT), 10-32 C | 175–770 µm | 6,000 psi (414 bar) | U-400, U-401 |
| 1/16" | PEEK | Lee MINSTAC® Alt, 6-40 FB | 175–770 µm | 1,500 psi (103 bar) | M-647, M-644-03 |
| 1/32" | FEP | MicroTight®, 6-32 C | 20–380 µm | 1,750 psi (121 bar) | F-126S |
| 1/32" | FEP | Valco Nanovolume® Alt, 6-40 C | 20–380 µm | 1,750 psi (121 bar) | M-645 |
| 1/32" | PEEK | MicroTight®, 6-32 C | 70–495 µm | 5,000 psi (345 bar) | F-126S |
| 1/32" | PEEK | Valco Nanovolume® Alt, 6-40 C | 70–495 µm | 3,250 psi (224 bar) | M-645 |
| * FB = Flat-Bottom; C = Coned; WT = Wrench-tightened MINSTAC is a registered trademark of The Lee Company, and Nanovolume is a registered trademark of Valco Instruments. Alt. refers to alternative fittings compatible with the mentioned ports from other manufacturers but do not endorse any specifically. |
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| ** Pressure limit estimated from sleeve dimension and material in combination with fitting system. | |||||
