What are the best practices for maintaining pipette accuracy?

1 Calibrate your pipettes regularly

Calibration is the process of checking and adjusting the accuracy and precision of your pipettes by comparing the dispensed volume with a reference standard. Calibration should be done according to the manufacturer's instructions and the frequency depends on the usage and type of your pipettes. You can either calibrate your pipettes in-house or send them to a certified service provider. Calibration certificates should be kept as a record of your pipette performance.

2 Follow proper pipetting technique

Pipetting technique is the way you handle and operate your pipettes and can have a great influence on the accuracy and consistency of measurements. Common pipetting errors include incorrect tip selection, improper tip attachment, inconsistent plunger operation, inaccurate immersion depth, and delivery angle. To avoid these mistakes, it is important to choose the right pipette and tip for your volume range and sample type. Additionally, attach the tip firmly and securely to the pipette, use the same pipette for the same sample throughout the experiment, pre-wet the tip by aspirating and dispensing the sample at least three times before taking the final measurement, hold the pipette vertically and immerse the tip to a consistent depth (usually 2-3 mm) when aspirating and dispensing, pause briefly after aspirating and before dispensing to allow the liquid to stabilize, dispense the liquid at a 90-degree angle to the container wall and touch off the tip to remove any residual liquid, and use reverse pipetting for viscous or volatile samples.

4 Clean and maintain your pipettes

Cleaning and maintenance are essential for keeping your pipettes in good working condition and preventing contamination, corrosion, or damage. The frequency of cleaning and maintenance should be done according to the manufacturer's recommendations and depends on the usage and type of your pipettes. You can do the cleaning and maintenance yourself or send them to a professional service. This may involve wiping the exterior of your pipettes with a damp cloth or a mild detergent, disassembling and cleaning the tip cone, piston, and seal with distilled water or a suitable solvent, lubricating the piston and seal with a silicone-based oil or grease, replacing worn or damaged parts such as tips, seals, springs, or o-rings, and performing a functional check to ensure the pipette is working properly.