Screw-Cap Micro-Vial

What is the Screw-Cap Micro-Vial?

A screw-cap micro-vial holds very small sample volumes with a reliable seal for autosamplers. It reduces dead volume when sample is scarce or expensive. It fits standard autosampler trays with 9 mm caps.

Overview

The micro-vial is a small glass or plastic container, often 0.1–1.2 mL, with a narrow conical interior and a screw cap carrying a PTFE-faced silicone septum. The conical shape concentrates the sample at the bottom so the needle can reach almost all of it, which is important when only microlitres are available, as in bioanalysis, mass spectrometry and precious synthetic products. Some designs include a fused insert, and some are wide-opening for easy filling. They fit standard autosampler trays and are compatible with 9 mm screw caps in many platforms. Because the volume is small, evaporation and adsorption have a proportionally larger effect, so the cap seal and glass deactivation matter, and vials should be filled close to the recommended level without overfilling.

How does it work?

A sample vial holds a small volume of liquid or headspace gas and is pierced by the autosampler needle through a septum. The vial material must not leach into or adsorb from the sample, so glass, usually borosilicate or Type I, is preferred for organic solvents and trace analysis, and polypropylene is used for aqueous and inorganic samples. The septum is the critical part: silicone, PTFE-faced silicone, butyl or natural rubber are chosen for chemical compatibility, resealing ability and pierce count. The cap and crimp or screw thread must hold the septum flat so no leak or evaporation occurs, because even small losses change concentrations over a long run. Surface treatment and low-adsorption glass help with polar or basic analytes, while amber glass protects light-sensitive compounds. Dimensions follow recognised standards so vials fit autosampler trays and magazines reliably.

What are the key features?

• Glass or plastic, 0.1–1.2 mL
• Conical interior for low dead volume
• Screw cap with PTFE-faced septum
• Fused insert options
• Fits standard autosampler trays
• Wide-opening option for filling

What are the technical specifications?

A typical screw-cap micro-vial configuration offers material of Glass or polypropylene, volume of 0.1–1.2 mL, interior of Conical, closure of 9 mm screw cap, septum of PTFE-faced silicone and dead volume of Low. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Screw-Cap Micro-Vial is used in bioanalysis, LC-MS sample introduction, precious sample analysis and microvolume storage. Across the wider Vials class, laboratories also deploy it for HPLC and UHPLC autosampling, gas chromatography injection and headspace analysis.

Which standards and certifications apply?

Relevant standards and methods include USP <660> (glass containers), EP 3.2.1 (glass containers for pharmaceutical use), ISO 8362 (injection containers and accessories), USP <661> (plastic components and systems), USP <1664> (assessment of drug product leachables) and GHS labelling requirements. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Fill vials to the recommended level, usually 50–75 % of the volume, so there is enough headspace for the autosampler and no sample is lost to the septum, and never overfill, because pressure can force liquid out or distort the septum. Use the correct crimp tool and torque, since a loose or over-tightened cap leaks or deforms the septum. Discard vials with damaged septa or distorted caps, and avoid reusing septa, because piercings do not reseal perfectly. Store standards in vials with minimal headspace, seal them well and use amber glass for light-sensitive compounds. Check that vials meet dimensional standards so they do not jam the autosampler, and use only the septa validated for the method, because a different septum can introduce new peaks.

How do I select the right Screw-Cap Micro-Vial?

Choose micro-vials when sample volume is very limited, and check compatibility with the autosampler and needle depth. RFQ: volume, material, cap size, insert and autosampler model. Provide the needle depth needed, the tray type and the autosampler model.

How does it compare with other Vials variants?

Choose the vial to fit the autosampler first, since tray and magazine dimensions are fixed, then choose the closure for the sample and the mobile phase. For reversed-phase HPLC with aqueous and organic mobile phases, a screw-top vial with a PTFE-faced silicone septum is common and convenient. For headspace analysis, use a vial rated for the pressure and temperature of the headspace sampler, with a septum that reseals after each of the several piercings. For GC, crimp-top vials with a low-bleed septum reduce background peaks. Choose amber glass for light-sensitive compounds, and low-adsorption or deactivated glass for basic and polar analytes that bind to active silanol sites. Confirm septum and cap compatibility, volume and any certification for trace metals or leachables, and check that inserts fit the vials and the autosampler needle.