Laboratory liquid handling quality assurance programs commonly focus on pipette calibration, repair and maintenance. Best practices are crucial in laboratories to provide reliable and error-free liquid delivery. Sources of errors in pipetting include improper operator technique to fluid viscosity issues, variable environmental factors and internal pipette component damage. The following measures can go a long way in ensuring accuracy in pipetting:
- Choose the right pipette that suits your application – There are different types of pipetting systems such as volumetric, micro pipettes and measuring pipettes. Based on the required volume, choose the right instrument. Test accuracy improves if there is a small difference between the volume minimum on the pipette and the volume being tested.
- A contamination-free pipette promotes accuracy – It is important to clean the pipette before and after every use. Check for any damage and ensure that the device is in working order and that there is no damage prior to beginning work.
- Service your pipette every 6-12 months – The service should include re-calibration, greasing of the moving parts and replacement of any work out seals or other parts.
- Following proper techniques is important for test accuracy – Such measures include pre-wetting the pipette tip, using consistent force while installing pipette tip, aspirating at 90 degrees and dispensing at 45 degrees, placing the tip just below the surface of the liquid to ensure that no air is being aspirated, and holding the equipment vertically when drawing liquid in.
- Keep it safe – Avoid holding the instrument when you are not using it. Always store it in an upright position. Environmental factors such as temperature, pressure, and humidity can affect the state of the pipette, leading to inaccurate results.
- Use well-fitting tips – Different types of pipette tips include gel loading tips, extended length, wide orifice tips, individually wrapped tips and sterilized filter tip. Poorly fitting tips allow air to escape when drawing up and dispensing, causing errors. A tip that is continually used for different tests and substances is susceptible to cross contamination. It is therefore recommended that a new pipette tip is used for each new liquid and that every new pipette tip is pre-rinsed. Ensure you using tips recommended by the manufacturer. High quality tips made from contamination-free polypropylene ensure accuracy.
Superior products such as the Ovation Adjustable Volume Pipettes from VistaLab Technologies come with special features to minimize errors and ensure reliable performance. These include one-way disposable nozzle, energy release button, low force, form-fitting plunger and an adjustable hook. These pipettes also reduce the major strains that cause pain and fatigue, and promote ergonomically correct positioning at every pipetting step.