How to Use an Automatic Pipette in the Laboratory
Introduction
Knowing how to use an automatic pipette in the laboratory is important for transferring liquids consistently during sample preparation, chemical analysis, and routine laboratory work. An automatic pipette is designed to support controlled liquid dispensing, but accurate results depend on selecting the right pipette, preparing it correctly, and following the operating procedure specified for its design.
Automatic pipettes do not all work in the same way. Some laboratory glass pipettes use a reservoir or dispensing arrangement, while adjustable micropipettes commonly use a piston mechanism and disposable tips. Understanding this difference helps laboratory personnel choose the right technique for their equipment.
This guide explains the automatic pipette working principle, the steps involved in using a pipette, common mistakes, cleaning practices, and important safety precautions.
What Is an Automatic Pipette?
An automatic pipette is a laboratory instrument designed to transfer or dispense a measured quantity of liquid. Its design helps make liquid handling more consistent during routine laboratory procedures.
Automatic pipettes are used in chemical laboratories, research facilities, educational institutions, and other settings where controlled liquid transfer is required. The appropriate type depends on the required volume, sample properties, and analytical procedure.
For example, LABIX Labware lists an Automatic Laboratory Pipette (Model LBX-1049), a glass pipette available in capacities from 5 mL to 100 mL. The website also lists an Automatic Pipette with Reservoir (Model LBX-1051), with capacities from 1 mL to 25 mL and different reservoir sizes. These are specific laboratory glassware designs, so users should follow their product instructions rather than assume they operate like a modern adjustable micropipette.
What Is an Automatic Pipette Used For?
An automatic pipette can support a range of liquid-handling tasks, depending on its design and capacity.
Common applications include:
- Transferring liquids during routine chemical analysis.
- Preparing solutions and samples.
- Dispensing liquids during laboratory procedures.
- Supporting educational experiments and demonstrations.
- Handling repeated liquid transfers in research and testing environments.
The pipette’s specifications and the requirements of the test determine whether it is suitable for a particular task.
Automatic Pipette Working Principle
The automatic pipette working principle depends on the mechanism used to draw in, measure, and dispense liquid. The term “automatic pipette” can describe different designs, so it is important to distinguish between them.
How Does a Reservoir-Type Automatic Pipette Work?
A reservoir-type laboratory pipette uses a connected liquid supply or reservoir arrangement to support repeated dispensing. Depending on the model, the mechanism controls the delivery of liquid through the pipette.
The user prepares the instrument according to the manufacturer’s instructions, ensures that the liquid path is ready for use, and operates the dispensing mechanism as specified. The design, filling method, and delivery process vary between products.
Do not assume that every reservoir-type pipette has the same controls or can dispense every volume. Check the model’s capacity, operating instructions, and specified tolerance before use.
How Does an Adjustable Micropipette Work?
An adjustable micropipette commonly uses a piston mechanism to aspirate and dispense small liquid volumes through a compatible disposable tip. The user sets a permitted volume, attaches the correct tip, and operates the plunger according to the manufacturer’s instructions.
Many air-displacement micropipettes use a first stop to aspirate the set volume and a second stop to help expel the remaining liquid during dispensing. Other designs, such as positive-displacement pipettes, work differently.
This distinction matters because the technique for an adjustable micropipette should not automatically be applied to a glass automatic pipette with a reservoir.
How to Use an Automatic Pipette in the Laboratory
The correct procedure depends on the instrument model. The following steps provide a general workflow for safe, consistent liquid handling. Always use the instructions supplied for your specific pipette.
Step 1: Select the Appropriate Pipette
Choose a pipette that suits the required volume, sample type, and intended procedure. Check the instrument’s capacity and tolerance before starting.
For routine laboratory glassware applications, a glass automatic pipette may be suitable for the specified dispensing range. For very small volumes, an appropriate micropipette may be more suitable.
Do not use a pipette outside its specified range or assume that two instruments with similar names have identical performance.
Step 2: Inspect and Prepare the Instrument
Before use, inspect the pipette for cracks, damage, residue, loose components, or contamination. Confirm that the reservoir, seals, tubing, tips, or other accessories are compatible with the instrument, where applicable.
Clean the components as instructed by the manufacturer. If the pipette requires assembly or priming, follow the model-specific procedure.
For adjustable micropipettes, confirm that the volume setting is within the permitted range and that the correct compatible tip is available.
Step 3: Prepare the Sample
Use a clean, appropriately labelled container for the liquid. Check that the sample is suitable for the pipette’s materials and intended use.
Mix the sample if the analytical method requires it. If the liquid is viscous, volatile, corrosive, or contains particles, consult the instrument instructions to confirm whether the pipette is suitable and whether a special technique is required.
Keep the working area organized to reduce the risk of spills, sample mix-ups, and contamination.
Step 4: Fill or Prime the Pipette
Follow the manufacturer’s instructions for filling the pipette or preparing its liquid pathway. A reservoir-type glass pipette and an adjustable micropipette require different procedures.
For a reservoir-type instrument, prepare the reservoir and liquid path as specified. Check for leaks or trapped air if the design and instructions identify these as relevant concerns.
For an adjustable micropipette, attach a compatible tip securely. Operate the plunger using the manufacturer’s recommended aspiration technique, keeping the tip at the appropriate depth and avoiding unnecessary movement.
Never fill a pipette by mouth. Use the intended dispensing mechanism or a suitable pipette aid.
Step 5: Dispense the Required Liquid Volume
Position the receiving container securely and operate the pipette according to its design. Use smooth, controlled movements and avoid sudden actions that may cause splashing or inconsistent delivery.
For a reservoir-type automatic pipette, use the specified control or dispensing mechanism and follow its delivery instructions.
For an adjustable air-displacement micropipette, the usual technique involves pressing the plunger to the first stop before aspiration, releasing it slowly, and dispensing with controlled pressure. The second-stop technique is commonly used to expel residual liquid when instructed by the manufacturer. Reverse pipetting or other methods may be required for certain liquids.
Do not apply the micropipette technique to a different pipette design unless its instructions explicitly require it.
Step 6: Check the Transfer and Record the Work
After dispensing, check that the liquid reached the intended container and that no visible spill or handling error occurred.
Where the method requires it, repeat the transfer or verify the delivered volume using an appropriate procedure. Record sample identifiers, instrument details, and any observations required by the laboratory’s documentation system.
If the instrument appears to leak, dispense inconsistently, or behave unexpectedly, stop using it until the problem has been investigated.
Common Mistakes to Avoid When Using an Automatic Pipette
Incorrect handling can affect volume delivery, sample integrity, and laboratory safety. Avoid these common mistakes:
- Using the wrong pipette: Confirm that the capacity and design match the procedure.
- Ignoring the manufacturer’s instructions: Different pipettes use different filling and dispensing mechanisms.
- Filling by mouth: Always use the intended mechanism or an appropriate pipette aid.
- Using damaged equipment: Cracks, worn components, or leaking connections may affect performance.
- Handling the sample carelessly: Prevent contamination by using clean containers and following the laboratory’s sample-handling procedure.
- Dispensing too quickly: Uncontrolled movements may cause splashing or inconsistent delivery.
- Ignoring liquid properties: Viscosity, volatility, and chemical compatibility can affect the choice of pipette and technique.
- Failing to check performance: Investigate inconsistent results rather than assuming every transfer is accurate.
A consistent procedure and suitable equipment help reduce avoidable errors.
Cleaning, Maintenance, and Storage of Automatic Pipettes
Proper care helps keep pipettes in usable condition and reduces the risk of contamination between samples. Cleaning and maintenance requirements vary according to the instrument’s construction and the liquids handled.
Cleaning After Use
Follow the manufacturer’s cleaning instructions for the pipette, reservoir, tips, and other components. Use compatible cleaning agents and rinsing procedures.
Do not immerse an adjustable micropipette’s body in liquid unless its manufacturer specifically permits it. Some components may require separate cleaning, disinfection, or replacement.
For glass pipettes, inspect the glass for cracks and remove residues using an appropriate procedure. Never continue using damaged glassware.
Inspection and Performance Checks
Check the instrument periodically for wear, leaks, blocked pathways, or other signs of malfunction. Where volume accuracy is critical, use the verification or calibration procedure appropriate to the pipette type.
Adjustable micropipettes may require periodic volume verification and servicing. Glass volumetric pipettes should be used according to their specified capacity, calibration designation, and delivery instructions.
Safe Storage
Store pipettes in a clean, dry location protected from dust, accidental impact, and chemical contamination. Use a suitable stand or storage arrangement when appropriate.
For example, a LABIX Pipette Stand is designed to organize and hold pipettes when they are not in use. Select a stand compatible with the pipette’s size and shape.
How to Choose the Right Automatic Pipette
Selecting a suitable pipette requires more than comparing capacity alone.
Required Volume and Tolerance
Determine the volume range required for the laboratory procedure. Review the manufacturer’s specifications and tolerance to confirm whether the instrument is appropriate for the intended work.
A pipette designed for larger volumes may not be suitable for very small-volume analytical tasks.
Instrument Design and Liquid Compatibility
Consider whether a glass automatic pipette, reservoir-type instrument, or adjustable micropipette best suits the application. Check compatibility with the sample and any cleaning agents that may contact the instrument.
For volatile, viscous, or hazardous liquids, consult the manufacturer’s instructions before selecting the pipette and operating technique.
Ease of Use and Maintenance
Consider how the instrument is filled, operated, cleaned, and stored. Also review the availability of compatible accessories, maintenance guidance, and performance verification procedures.
You can browse the LABIX Labware Pipettes and Burettes category to compare listed pipette designs and identify options that may suit your laboratory requirements.
Frequently Asked Questions
1. What is the main purpose of an automatic pipette?
An automatic pipette is used to transfer or dispense liquid in a controlled manner. Its applications and volume range depend on the instrument’s design and specifications.
2. What is the working principle of an automatic pipette?
The working principle depends on the model. Some instruments use a reservoir and dispensing arrangement, while adjustable micropipettes commonly use a piston mechanism to aspirate and dispense liquid.
3. Can an automatic pipette be used for every liquid?
No. The instrument must be compatible with the liquid’s properties and the intended procedure. Viscosity, volatility, chemical compatibility, and required volume can affect pipette selection.
4. How can pipetting errors be reduced?
Use the correct instrument, follow its operating instructions, handle liquids consistently, prevent contamination, and verify performance when required. Do not use damaged or malfunctioning equipment.
5. How often should a laboratory pipette be calibrated?
The appropriate interval depends on the instrument type, frequency of use, manufacturer recommendations, laboratory quality procedures, and the accuracy required. Follow the laboratory’s documented verification and calibration schedule.
6. How should an automatic pipette be stored?
Clean and prepare the pipette according to the manufacturer’s instructions, then store it in a clean, dry, protected location. A compatible pipette stand can help prevent accidental damage and keep the workspace organized.
Conclusion
Learning how to use an automatic pipette in the laboratory involves selecting the correct instrument, preparing it according to its design, dispensing liquid carefully, and following appropriate cleaning and maintenance procedures. The working principle and operating technique differ between reservoir-type glass pipettes and adjustable micropipettes, so the manufacturer’s instructions should always guide use. Proper selection, consistent handling, and performance checks help laboratories reduce errors and maintain reliable liquid transfer. Explore the LABIX Labware pipette range to review available glass pipettes and choose an option that matches your laboratory’s requirements.
