A Novel Way to Prevent Sample Evaporation in Microplates

Post date : August 31, 2026　Update date : September 08, 2026

Microplates are widely used in life science, pharmaceutical, and analytical laboratories. However, solvent evaporation can compromise sample integrity, analytical accuracy, and experimental reproducibility, especially when sample volumes are low or plates remain exposed for extended periods.

This article explains why sample evaporation matters, examines the conditions that increase solvent loss, compares common prevention methods, and explores a novel approach that keeps the plate covered while individual wells remain accessible.

Why Does Sample Evaporation Matter?

Sample evaporation does more than reduce the amount of liquid in each well. Even small volume changes can affect concentration, analytical accuracy, and reproducibility, particularly in low-volume microplate workflows.

Changes in Sample Concentration

As solvent evaporates, the remaining analytes become more concentrated. This may affect quantitative measurements, calibration results, and downstream analyses.

Reduced Reproducibility

Uneven evaporation across a microplate may cause samples prepared under the same conditions to produce different results. This can complicate troubleshooting and make experiments more difficult to reproduce.

Loss of Valuable Samples

For precious or low-volume samples, evaporation may leave insufficient material for repeat analysis or confirmation testing.

Why Does Sample Evaporation Occur in Microplates?

Sample evaporation is influenced by several environmental and workflow-related factors. Understanding these causes helps laboratories choose a more appropriate evaporation prevention strategy.

Low Sample Volumes

Modern analytical workflows often use only a few microliters of sample. At these volumes, even a small amount of solvent loss can represent a meaningful percentage of the total volume and change sample concentration.

Temperature

Higher temperatures increase solvent evaporation during incubation, sample preparation, or storage. Even room-temperature exposure can become significant when plates remain uncovered for extended periods.

Airflow

Air movement in fume hoods, biosafety cabinets, laboratory ventilation systems, or around analytical instruments removes solvent vapor from above the liquid surface and allows evaporation to continue.

Extended Waiting Times

Samples may remain on an autosampler tray, laboratory bench, or storage rack for hours before analysis is complete. Gradual evaporation during this period can create differences between samples measured at the beginning and end of a sequence.

Repeated Plate Access

Repeated pipetting or automated sampling can expose wells multiple times throughout a workflow, increasing the opportunity for solvent loss if the sealing method is not designed for repeated access.

Common Solutions for Preventing Sample Evaporation

Several sealing solutions are used to reduce sample evaporation in microplates. The most suitable option depends on the required sealing performance, storage period, plate format, and how frequently samples need to be accessed.

Adhesive Plate Seals

Adhesive plate seals are widely used because they are easy to apply and available in a variety of materials for storage, incubation, and analytical workflows.

However, conventional adhesive seals often need to be removed or peeled back when samples are accessed. Repeated handling can interrupt the workflow, expose neighboring wells, and reduce sealing consistency.

In some analytical applications, laboratories also prefer to minimize direct contact between samples and adhesive materials because of concerns about potential contamination or unintended interactions. This consideration is particularly relevant for valuable samples and highly sensitive analyses.

Foil Seals

Foil seals can provide a strong barrier against evaporation and contamination, making them useful for storage and other applications requiring limited moisture or gas exchange.

Many foil seals are intended for single use. Once pierced or removed, they may not provide the same level of protection, which can make them less practical for workflows requiring frequent sample access.

Silicone Mats

Silicone mats can provide a tight seal and strong evaporation protection. Some are available with pre-slit designs, allowing repeated access with pipette tips or needles without removing the mat.

When selecting a silicone mat, check solvent compatibility, plate fit, and suitability for the intended sampling system, as these can vary by product.

Why RAPID Slit Seal™ Helps Prevent Sample Evaporation

RAPID Slit Seal™ is an adhesive plate seal with precision-cut slits positioned over the wells. Pipette tips and autosampler needles can pass through the slits while the rest of the microplate remains covered.

This design helps reduce unnecessary exposure during repeated handling. Instead of peeling back or removing the entire plate seal, users can access individual wells while maintaining coverage across the plate.

No Need to Remove the Entire Seal

With many conventional adhesive plate seals, accessing samples requires peeling back or removing part of the seal. This can expose multiple wells even when only one sample needs to be accessed.

RAPID Slit Seal™ allows access through the slit above each well, helping the surrounding wells remain covered during pipetting or automated sampling.

Repeated Access with Less Sample Exposure

Repeated pipetting and analytical sampling can increase the time that samples are exposed to the surrounding environment. By keeping the plate covered between access points, RAPID Slit Seal™ helps limit exposure that may contribute to sample evaporation.

Suitable for Pipettes and Autosampler Needles

The pre-cut slits are designed to allow pipette tips and autosampler needles to enter individual wells. This makes RAPID Slit Seal™ suitable for both manual sample handling and automated analytical workflows.

Reduced Adhesive Contact with Sampling Tools

Because the pipette tip or needle passes through a pre-cut slit rather than piercing directly through an adhesive surface, RAPID Slit Seal™ can help reduce contact between the sampling tool and the adhesive layer.

The area directly above each well is designed without adhesive, helping minimize contact between the sample and adhesive materials while allowing direct access through the slit. This can be beneficial in workflows where adhesive transfer or potential sample interaction is a concern.

Typical Applications

RAPID Slit Seal™ is particularly useful in workflows that require repeated access to individual wells while the rest of the microplate remains covered.

LC-MS and HPLC Analysis

Microplates may remain on an autosampler for extended periods while samples are analyzed sequentially. Keeping wells covered between injections can help reduce solvent loss and concentration changes during the analytical run.

Compound Libraries

Compound libraries often require samples to be accessed more than once. Individual-well access helps users retrieve selected samples without repeatedly uncovering the entire plate.

Drug Discovery and High-Throughput Workflows

Screening and sample-preparation workflows may involve repeated pipetting, transfers, or automated sampling. A seal that remains on the plate can reduce additional handling while supporting efficient access to individual wells.

Routine Sample Handling

Laboratories may also use RAPID Slit Seal™ for routine workflows in which a microplate must stay covered while samples are added, removed, or measured at different stages.

Frequently Asked Questions

What causes sample evaporation in microplates?

Sample evaporation is influenced by sample volume, temperature, airflow, waiting time, and how frequently the plate is accessed. Low-volume samples are particularly sensitive because even a small absolute loss can noticeably change concentration.

How can sample evaporation be reduced in 96-well plates?

Using an appropriate sealing solution, limiting unnecessary exposure, controlling temperature and airflow, and reducing waiting time can all help. The best option depends on whether the plate is stored, incubated, manually handled, or accessed by an autosampler.

Can samples be accessed without removing the plate seal?

Yes. RAPID Slit Seal™ has precision-cut slits that allow pipette tips or autosampler needles to access individual wells without removing the entire seal.

How is RAPID Slit Seal™ different from a conventional adhesive plate seal?

A conventional adhesive plate seal may need to be peeled back, removed, or pierced through the adhesive layer. RAPID Slit Seal™ provides pre-cut openings over the wells, allowing samples to be accessed while the surrounding plate remains covered.

Is RAPID Slit Seal™ compatible with autosamplers?

RAPID Slit Seal™ is designed for access by autosampler needles as well as pipette tips. Compatibility should still be evaluated with the specific plate, needle, instrument, and analytical conditions used in the laboratory.

Does a plate seal completely stop sample evaporation?

No sealing solution should be assumed to eliminate evaporation under every condition. Performance can vary with solvent, temperature, plate type, storage time, seal application, and the number of times samples are accessed.

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