For use as a PCR overlay


  • Innovative hydrophobic, low-viscosity PCR encapsulation barrier
  • Ensures high success rates in precision applications such as real-time PCR
  • Eliminates the need for tube caps, accelerating reaction setup

Useful Resources

Vapor-Lock (50 ml)

Cat. No. / ID: 981611

50 ml Vapor-Lock (10–40 µl/reaction)
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Vapor-Lock is an accessory for use with the Rotor-Gene Q thermal cycler.

Product Details

Vapor-Lock is an innovative hydrophobic, low-viscosity PCR encapsulation barrier. As little as 10 µl easy-to-pipet Vapor-Lock creates an effective barrier. Vapor-Lock enables reaction overlays that prevent evaporation and eliminate the need for tube caps. Unlike mineral oil, Vapor-Lock does not contaminate or inhibit PCR.


Use of Vapor-Lock for reaction overlay eliminates the need to cap tubes. In experiments comparing CT values, similar results were obtained from reactions in capped tubes compared to reactions overlaid with Vapor-Lock in uncapped tubes (see figure " Vapor-Lock eliminates need for tube caps").

Small reaction volumes (e.g., reaction volumes in a 384-well plate) typically exhibit poor reproducibility and are extremely difficult to run successfully on many real-time instruments. However, the Rotor-Gene Q cycler constantly centrifuges samples during a run, keeping the reaction at the bottom of the tube aligned with the optical pathway (see figure " Principle of Vapor-Lock"). When working with small reaction volumes, it is important to avoid any evaporation. Vapor-Lock prevents evaporation and has been succesfully used to ensure successful amplification for reaction volumes as low as 5 µl (see figure " Successful amplification using small reaction volumes").

See figures


Evaporation can occur during thermal cycling, resulting in changes in the reaction volume and the concentration of each reaction component. Vapor-Lock prevents evaporation, ensuring high success rates in precision applications such as quantitative real-time PCR and high-resolution melting (HRM). Vapor-Lock looks and behaves like aqueous buffer. It sits above the aqueous phase, forming a layer on top of the aqueous sample (see figure " Principle of Vapor-Lock"). Vapor-Lock has low viscosity and low specific gravity, allowing aqueous droplets over approximately 1 µl to drop easily through the Vapor-Lock layer to the aqueous sample underneath.

Long reaction setup times, which can occur when working with large numbers of samples in strip tubes or multiwell plates, increase the risk of sample evaporation which can compromise the success of an experiment. Vapor-Lock completely eliminates the need for caps which accelerates reaction setup. Vapor-Lock overlays the samples, preventing evaporation and increasing the reliability of results.

In contrast to mineral oil, Vapor-Lock does not contaminate or inhibit PCR. The background fluorescence of Vapor-Lock is less than one fluorescence unit (see figure " Minimal autofluorescence of Vapor-Lock").

Vapor-Lock is fully compatible with the QIAgility instrument for high-precision, automated reaction setup. It is also highly suited for use with the Rotor-Gene Q cycler.

Vapor-Lock specifications
Physical propertiesPCR-safe; no known contaminants, including DNA, RNA, enzymes, metals, salts or other trace elements
PuritySynthetic, high-molecular-weight polymer; hydrophobic, colorless, odorless, nonhazardous
AutofluorescenceNone detected spanning ultraviolet to infra red (excitation 36–680 nm; emission 460–712 nm)
Viscosity≥5 centistoke
Vapor pressure<1 mm Hg
Boiling point>120°C
Flash point<125°C
Solubility<100 ppb
See figures


Vapor-Lock is compatible with both manual and automated reaction setup. We recommend adding Vapor-Lock to reaction tubes prior to any reaction components. Gentle centrifugation during a normal Rotor-Gene Q run ensures full partitioning of the Vapor-Lock and aqueous reaction components into 2 layers (i.e., Vapor-Lock on top and reaction mix underneath). If not using a Rotor-Gene Q cycler, we recommend briefly centrifuging samples prior to cycling.


Vapor-Lock is highly suited for use in PCR and HRM applications, including:

  • Gene expression analysis
  • Genotyping
  • Mutation scanning

Supporting data and figures


Kit Handbooks (1)
(EN) - Vapor-Lock
PDF (517KB)
For use as a PCR overlay


If Vapor-Lock is used to overlay PCR reactions, which volume should be entered as reaction volume in the Rotor-Gene Q Software?

The reaction volume to be entered in the Rotor-Gene Q software should be the sum of the PCR reaction volume and the volume of Vapor-Lock.



FAQ ID -2150
Can Vapor-Lock be used with samples processed on the QIAgility?

Vapor-Lock is fully compatible with the QIAgility instrument for high-precision, automated reaction setup. It is also highly suited for use with the Rotor-Gene Q cycler. For support to program your QIAgility instrument for use with Vapor-Lock, please contact your local QIAGEN Technical Support Department.



FAQ ID -2153