MicroTight Connectors

MicroTight Connectors

Idex MicroTight® connectors are precision-engineered fittings designed for secure, repeatable connections in capillary and microfluidic flow paths. Built for chromatography, LC-MS interfaces, and research-grade fluid handling, MicroTight components help you create true zero dead volume (ZDV) connections so tubing ends align cleanly—reducing dispersion, minimizing carryover, and supporting stable, low-noise performance in high-sensitivity methods.

Whether you’re joining capillary tubing directly, transitioning from standard 1/16” OD lines to capillary dimensions, or building micro-scale split/merge geometries near a detector, MicroTight solutions provide the alignment aids, sleeves, and adapter configurations needed for consistent results. Many configurations support direct-connect options for 1/32” OD and 360 µm OD tubing, making MicroTight a flexible platform for modern analytical workflows.

Product Categories

VHP MicroTight Connectors

VHP MicroTight® Unions combine a durable stainless steel body with a unique stainless steel union capsule and biocompatible PK/PEEK fittings for excellent chemical compatibility and conductivity—ideal for electrical interfacing in select LC-MS applications. These unions provide zero dead volume alignment so two pieces of tubing butt together cleanly, with pressure ratings up to 15,000 psi (1,034 bar). Options support direct-connect 1/32” OD and 360 µm OD tubing.

MicroTight Unions

MicroTight Unions are designed to connect capillary tubing with precision and repeatability. They deliver true ZDV performance by allowing tubing ends to meet directly, using the included gauges and plugs to ensure correct alignment. The result is a clean, uninterrupted flow path that supports sharper peaks and better reproducibility in micro-scale separations.

MicroTight Adapters

MicroTight Adapters make it simple to create reliable transitions from common 1/16” OD tubing to capillary connections. Many versions also provide direct-connect options for 1/32” OD and 360 µm OD tubing. These adapters are engineered to maintain a true ZDV connection for minimal disruption of the fluidic pathway.

VHP MicroTight Adapters

These very high pressure (VHP) adapters are built to connect fused silica and other capillary tubing to standard 1/16” OD tubing or to standard luer-lock connectors. Available versions support .025” (MicroTight Sleeves), 1/32”, and 360 µm ODs, with pressure ratings up to 12,000 psi (828 bar) for demanding microflow and high-pressure applications.

PEEK MicroTight Adapters

PEEK MicroTight adapters provide a chemically resistant solution for connecting fused silica and other capillary tubing to standard 1/16” OD tubing or luer-lock connectors. Versions are available for .025” (MicroTight Sleeves), 1/32”, and 360 µm OD connections, offering a lightweight, inert option well-suited for many analytical solvent systems.

PEEK Tees & Crosses

PEEK Tees and Crosses are designed to withstand environmental stresses in higher pressure regions of a system while delivering excellent chemical resistance. Featured PEEK MicroTees and micro-scale crosses join capillary tubing with geometries that support stable flow. Many researchers use a PEEK MicroTee to introduce fluid just prior to a Mass Spectrometer, taking advantage of its internal design and the electrical resistance of PEEK.

Why MicroTight for Capillary & Microflow Systems?

  • True ZDV connections help preserve peak shape by minimizing dead volume and turbulence.
  • Cleaner transitions from 1/16” tubing to capillary sizes for microflow methods.
  • High-pressure options available for demanding systems and compact instrument plumbing.
  • Material choices (stainless steel, PK/PEEK, PEEK) to match solvent compatibility and application needs.
PART NO DESCRIPTION THREADS THRU-HOLE SWEPT VOL. PRESSURE RATING MATERIAL
   
MICROTIGHT UNIONS
P-720 True ZDV Union for MicroTight Sleeves 6-32 Coned N/A N/A 4,000 PSI (276 bar) PEEK
P-771 True ZDV Union for 1/32" OD 6-32 Coned N/A N/A 5,000 PSI (345 bar) PEEK
P-772 Union for 360 µm OD 5/16-24 Coned 0.006" (0.150 mm) 5 nL 5,000 PSI (345 bar) PEEK
P-874 MicroElbow for MicroTight Sleeves 5/16-24 Coned 0.006" (0.150 mm) 20 nL 4,000 PSI (276 bar) PEEK
REPLACEMENT GAUGE PLUGS (TO ACHIEVE TRUE ZDV CONNECTIONS WITH P-720 AND P-771 UNIONS)
P-553 Gauge Plug 6/32 Coned N/A N/A N/A Delrin®
UNIONS
M-572 Conductive Union for 360 µm OD 5/16-24 Coned 0.011" (0.279 mm) 16 nL 5,000 PSI (345 bar) PEEK/SS
PART NO DESCRIPTION TUBING OD THREADS THREADS SWEPT VOL. PRESSURE MATERIAL COLOR
MICROTIGHT ADAPTERS
P-770True ZDV, Tubing to MicroTight Tubing Sleeve1/16"10-32 Coned6-32 ConedN/A4,000 PSIPEEKNatural
P-881True ZDV1/16" – 1/32"10-32 Coned6-32 ConedN/A5,000 PSIPEEKRed
P-882True ZDV1/16" – 360 µm10-32 Coned6-32 ConedN/A5,000 PSIPEEKBlue
UH-630VHP1/16" – 1/32"10-32 Coned6-32 ConedN/A12,000 PSISSSS/Black
UH-634VHP1/16" – 360 µm10-32 Coned6-32 ConedN/A12,000 PSISSSS/Black
UH-753VHP Tee1/16" – 360 µm10-32 Coned5/16-24 Coned152 nL15,000 PSI*SSSS/Black
1958-01 1/16" – 1/32"10-32 ConedM4×0.7 Coned16 nL30,000 PSI*SSSS
UH-631-01VHP1/16" – 1/32"10-32 Coned6-40 Coned13 nL30,000 PSI*SSSS
UH-906Cross1/16" – 360 µm10-32 Coned5/16-24 Coned110 nL15,000 PSI*SSSS/Black
LUER-TO-MICROTIGHT ADAPTER
P-662Luer-to-MicroTight Adapter360 µmLuer5/16-24 Coned14 nL45 PSIPEEKNatural
REPLACEMENT GAUGE PLUGS
P-554Gauge Plug—10-32 Coned—N/AN/ADelrin®White
* Pressure rating depends upon the fitting used.
PART NO DESCRIPTION TUBING OD THREADS THRU-HOLE SWEPT VOL. PRESSURE RATING
PEEK MICROTEES & CROSS
P-775 MicroTee 1/16" 5/16-24 Coned 0.006" (0.15 mm) 29 nL 4,000 PSI (276 bar)
P-777 MicroCross 1/16" 5/16-24 Coned 0.006" (0.15 mm) 39 nL 4,000 PSI (276 bar)
P-875 MicroTee with Mounting Hole, for MicroTight Sleeves 1/16" 5/16-24 Coned 0.006" (0.15 mm) 29 nL 4,000 PSI (276 bar)
P-885 MicroTee 1/32" 5/16-24 Coned 0.006" (0.15 mm) 29 nL 5,000 PSI (345 bar)
P-887 MicroCross 1/32" 5/16-24 Coned 0.006" (0.15 mm) 38 nL 5,000 PSI (345 bar)
P-888 MicroTee 360 µm 5/16-24 Coned 0.006" (0.15 mm) 29 nL 5,000 PSI (345 bar)
P-889 MicroCross 360 µm 5/16-24 Coned 0.006" (0.15 mm) 38 nL 5,000 PSI (345 bar)
P-890 MicroTee 1/16" 5/16-24 Coned 0.006" (0.15 mm) 58 nL 5,000 PSI (345 bar)
P-891 MicroCross 1/16" 5/16-24 Coned 0.006" (0.15 mm) 81 nL 5,000 PSI (345 bar)
Key Definitions ▸
MicroTight® Connector
A precision capillary fitting system designed to connect small-OD tubing (such as 1/32” or 360 µm) with accurate alignment and a low-volume flow path for microflow LC and LC-MS applications.
Zero Dead Volume (ZDV)
A connection characteristic indicating minimal or no internal void space at the junction where two tubing ends meet, helping reduce band broadening, peak tailing, and carryover in capillary-scale separations.
VHP (Very High Pressure)
A designation for fittings engineered to operate in high-pressure regions of a system, commonly used for UHPLC and microflow workflows. VHP MicroTight connectors support elevated pressures (depending on configuration).
Capillary Tubing (360 µm / 1/32” OD)
Small-format tubing used in microfluidic and microflow chromatography. Common outer diameters include 360 µm and 1/32” OD, enabling low flow rates and improved sensitivity in LC-MS interfaces.
MicroTight Sleeve (.025”)
A small sleeve used to adapt capillary tubing (commonly fused silica) to MicroTight fittings, providing reliable alignment and a stable interface for true ZDV connections.
Direct-Connect Adapter
An adapter that allows capillary tubing to connect directly to standard 1/16” OD tubing hardware or common ports without unnecessary unions, helping maintain a low-volume flow path.
PK/PEEK Fittings
High-performance polymer fitting components (PEEK-family materials) used for chemical resistance and electrical insulation. Often selected for capillary connections and LC-MS interfaces where inertness and non-conductivity matter.
Frequently Asked Questions ▸
What are Idex MicroTight® connectors used for?
Idex MicroTight connectors are designed to make reliable, low-volume connections for capillary-scale tubing in microflow chromatography, microfluidics, and LC-MS setups. They help maintain an uninterrupted flow path while supporting small OD formats such as 1/32” and 360 µm.
What does “ZDV” (Zero Dead Volume) mean for MicroTight connections?
ZDV means the connection is designed so tubing ends align and meet cleanly with minimal internal void space at the junction. This reduces dispersion, improves peak shape, and helps minimize carryover—especially important for capillary and microflow separations.
What tubing sizes do MicroTight connectors typically support?
Many MicroTight configurations support direct-connect options for 1/32” OD and 360 µm OD tubing, and certain adapters are designed to transition between standard 1/16” OD systems and capillary tubing (including sleeve-based options such as .025” MicroTight sleeves).
When should I choose VHP MicroTight connectors vs standard MicroTight?
Choose VHP MicroTight connectors for higher-pressure regions of your system (such as UHPLC or high-pressure capillary applications). Standard MicroTight connectors are ideal for capillary alignment and low-volume connections where extreme pressure ratings are not required.
Do MicroTight unions require special tools to install?
Most MicroTight connections are designed for straightforward installation using the correct fittings, gauges, and plugs to align tubing ends. Always follow the fitting instructions for your exact configuration to ensure proper alignment and a dependable ZDV seal.
Why are PEEK MicroTight tees and crosses common near an LC-MS source?
PEEK MicroTight tees and crosses can be useful for adding a makeup flow or introducing reagents close to the MS source while keeping dispersion low. PEEK is also valued for chemical resistance and electrical insulation, which can be beneficial in certain LC-MS interfacing setups.