Forward vs Reverse Pipetting

When and How to Use Each Technique

Forward pipetting and reverse pipetting are two common liquid-handling techniques. Choosing the right method helps improve accuracy, reduce bubbles, and protect sensitive measurement surfaces.

What Is Forward Pipetting?

Forward pipetting is the standard technique used for most aqueous samples. The set volume is aspirated and then fully dispensed.

Best for:

  • Water-like samples
  • Routine liquid handling
  • Standard buffer or reagent transfer
Forward vs Reverse Pipetting when to Use Each Technique

Forward Pipetting Technique

Basic Steps:
  1. Press the plunger to the first stop.
  2. Immerse the pipette tip just below the surface of the sample.
  3. Aspirate the sample.
  4. Dispense by pressing to the first stop, then the second stop.
  5. Remove and discard the tip.
Implen Forward Pipetting Technique

What Is Reverse Pipetting?

Reverse pipetting is useful when working with liquids that are difficult to dispense accurately, especially samples with low surface tension or high vapor pressure, such as highly volatile liquids. However, reverse pipetting is also suitable for aqueous solutions and is therefore the preferred technique for highly accurate pipetting and sample analysis.

In reverse pipetting, slightly more liquid is aspirated than is dispensed. The extra liquid remains in the tip and is discarded afterward.

Best for:
  • Volatile samples
  • Foaming liquids
  • Viscous liquids
  • Small-volume measurements
  • Applications where bubbles must be avoided
reverse pipetting low surface tension high vapor pressure
reverse pipetting technique for volatile samples

Why Use Reverse Pipetting?

Reverse pipetting helps reduce measurement errors, improve volume consistency, and minimize bubble formation during liquid handling. It is especially useful for preventing unwanted splashing and protecting delicate measurement surfaces when working with volatile or difficult-to-dispense samples.

Reverse Pipetting on a Pedestal Measurement Surface

When applying a sample to the pedestal window:
  1. Press the plunger to the second stop.
  2. Immerse the pipette tip just below the surface of the sample.
  3. Aspirate slightly more than the required sample volume.
  4. Dispense the sample onto the sample window by pressing the plunger to the first stop only. Note: Do not expel the residual liquid remaining in the tip.
  5. Withdraw the pipette tip without touching the measurement surface.
  6. Close the lid arm and proceed with the measurement.
  7. Discard the used pipette tip according to laboratory waste guidelines.

Important: The residual liquid left in the tip is intentional. Expelling it can affect delivery accuracy and introduce bubbles onto the measurement window.

Implen Reverse Pipetting Technique

Quick Comparison

Feature Forward Pipetting Reverse Pipetting
Dispensing method Full dispense Dispense to first stop only
Residual liquid in tip Expelled Left in tip
Best for Standard liquids Volatile, foaming, or viscous samples
Bubble risk Higher with difficult liquids Lower
Accuracy with volatile samples Less reliable More reliable
Prof. Beer's Insight
Prof. Beer's Insight
Precision in liquid handling comes from using the right technique for the right sample. Reverse pipetting helps reduce bubbles, improve consistency, and protect sensitive measurement surfaces when accuracy matters most.

Choosing the Right Technique

Both methods have an important place in the laboratory. While forward pipetting remains common for routine liquid handling, reverse pipetting is generally preferred when accuracy and consistency are important, particularly for volatile, viscous, or foam-prone samples.

Because reverse pipetting also performs reliably with standard aqueous solutions, it can serve as a broadly applicable method across a wide range of pipetting tasks.

Understanding when to use each technique can improve measurement accuracy, reduce variability, and help protect sensitive analytical surfaces from contamination or sample disruption.

Scroll to Top