1 / 23

Improving Pipetting Techniques For better accuracy and performance

Improving Pipetting Techniques For better accuracy and performance. Pipetting 360 °. Part of the Good Pipetting Series of Seminars. Improving Pipetting Techniques. Definitions Minimizing errors Hands-on Workshop (optional). Air-displacement Pipette. Piston. Shaft. Air space. Disposable

savea
Download Presentation

Improving Pipetting Techniques For better accuracy and performance

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Improving Pipetting TechniquesFor better accuracy and performance Pipetting 360° Part of the Good Pipetting Series of Seminars

  2. Improving Pipetting Techniques • Definitions • Minimizing errors • Hands-on Workshop (optional)

  3. Air-displacement Pipette Piston Shaft Air space Disposable tip Sample

  4. Air-displacement pipetting cycle Depress Hold Tip Ejection Aspirate Dispense through Blowout

  5. Pipette performance specifications • Accuracy +/- 1% • Precision 0.25% to 0.33% • Ultramicro pipette specifications are wider Precise but not accurate Not precise or accurate Preciseandaccurate

  6. Basic techniques for minimizing errors • Optimizing volume range • Setting the micrometer • Tip immersion angle • Tip immersion depth • Tip immersion time • Pre-rinsing pipette tips • Aspiration rate • Dispensing techniques • Hand-warming effects Errors from poor technique can range from 0.1% - 5% or more

  7. Impact of errors in technique • Errors less than 0.5% • Calibrators need to be aware as all errors can impact results • Errors 0.6% - 1% • Normal users need to decide the importance of each error versus the extra time and effort required • Errors greater than 1% • Everyone needs to be aware of these errors

  8. Optimizing volume range • Normal Range • 10% - 100% of volume • Operating at 10% range requires good technique • Optimized Range • typically 35% - 100% of volume • Less technique dependent • Assures accuracy and precision Optimizing volumerangetypically improves accuracy up to 1%

  9. Setting the micrometer • Approach each volume in the same direction each time • Turn micrometer 1/3 revolution above desired volume • Dial down to volume setting Correctly setting the micrometer improves accuracy up to 0.5%

  10. Tip immersion angle Incorrectimmersionangle Correctimmersionangle Aspirating with the pipetteperpendicular improvesaccuracy up to 0.5%,ultramicroup to 2.5%

  11. Depth Tip immersion depth Recommended immersion depth improves accuracy up to 1%, ultramicro up to 5%

  12. Tip immersion time for macrovolume pipettes • Maintain tip immersion time of 1 second (minimum) after aspiration • Withdraw tip slowly, smoothly from liquid source • Important for large volume samples and viscous liquid samples

  13. 100.2 100.1 10 model Normalized Volume (%) 200 model 100.0 1000 model 99.9 99.8 0 1 2 Number ofPre-rinses Effect of pre-rinsing tips

  14. Pre-rinsing pipette tips • Pre-rinse tip with same liquid that is being dispensed • Aspirate sample into tip, and then dispense back into reservoir or to waste • Pre-rinsing provides identicalcontactsurfaces for all aliquots Two pre-rinses provides up to 0.2% greater accuracy when used with aqueous liquids

  15. Aspiration rate effects • Use consistent • Pipetting rhythm • Pressure on plunger • Speed and smoothness Inconsistentaspirationcan affect accuracy up to 1%

  16. Aspiration rate effects • Use consistent • Pipetting rhythm • Pressure on plunger • Speed and smoothness • Aspiration too quickly • Liquid splash-up into shaft damaging piston and seal • Introduces aerosols and sample cross-contamination Tooquickaspirationcanaffectaccuracyupto5%ormore

  17. Dispensing techniques • Thin-wall, FinePointTMtips provide maximum droplet dispensing • Threetechniques • Alongside-wall

  18. Dispensing techniques • Thin-wall, FinePointTMtips provide maximum droplet dispensing • Three techniques • Along side-wall 2) Above vessel / liquid surface

  19. Dispensing techniques • Thin-wall, FinePointTMtips provide maximum droplet dispensing • Three techniques 1) Along side-wall 2) Above vessel/ liquid surface 3)Directlyintoliquid Correctdispensingtechniqueimprovesaccuracyupto1%

  20. Hand-warming effects Prolongedhand-warmingintroduceserrorsofupto0.2%for a high-quality pipette, 0.5% for others

  21. Improving pipetting techniques summary • Optimizing volume range • Setting the micrometer • Tip immersion angle • Tip immersion depth • Tip immersion time • Pre-rinsing pipette tips • Aspiration rate effects • Dispensing techniques • Hand-warming effects

  22. Errors in pipetting Small errors are important to calibration technicians, everyone should care about large errors.

  23. Good Pipetting Technique = Minimal Errors = Good Performance Rainin Instrument, LLC a METTLER TOLEDO Company • 800-472-4646 • www.rainin.com • pipets@rainin.com

More Related