Taking Care of Liquid Handling Instruments When Not in Use For Long

Taking Care of Liquid Handling Instruments When Not in Use For Long

To keep your lab up and running, it is crucial to invest in quality and robust liquid handling instruments. Liquid handling instruments, automated or otherwise, reap accurate results during an experiment. These instruments help carry out critical tasks ranging from the discovery of drugs, adding enzymes to an assay plate and so on. Labs, the world over, use such instruments almost every day, working with the minutest reagent volumes, and assisting in accurately detecting diseases, preparing their vaccines, detecting chemicals, etc. 

Like other lab instruments, liquid handling instruments can be put away for a long time when not in use. When not used for a long time, an instrument may exhibit error due to reagent or dust deposits. To completely rule out that possibility, here are a few useful steps on how you can maintain, store and troubleshoot your own liquid handling instruments to ensure efficient and error-free performance. 

Product Maintenance

  • Cleaning
    The most essential step for good maintenance of liquid handling instruments is cleaning. Skipping this step may result in inaccurate results due to residue deposit and/or the presence of other contaminants. So, clean your instruments and at the same time, keep in mind that the cleaning agent or tool you use doesn’t leave behind any residue; not even the microscopic fibres of a paper towel.Liquid handling instruments from Microlit are easy to maintain as the innovative Springless ValveTM technology in Bottle Top Dispensers and E-burettes prevents corrosion and residue formation. If needed, you may clean your instruments internally by running them twice in distilled water, especially after long term storage. The external body can then be cleaned with an alcohol
    swab.As for the maintenance of micropipettes, special attention should be paid to the tip cone and the whole external body should be cleaned with solvents containing 70% ethanol.
  • Disassembling & assembling
    After disassembling the instrument for cleaning, it is crucial to assemble it in the correct manner to ensure proper functioning. Luckily, Microlit instruments do not need to be disassembled frequently for cleaning, thereby making your life easy.

However, you should still be aware of how to disassemble and assemble a micropipette and a bottle top dispenser

  • Calibration
    Instruments, when kept aside for a long duration, may develop errors. This necessitates for them to be calibrated periodically. Since liquid handling instruments are calibrated using different methods, it is crucial to keep a check on how you are calibrating your instrument.

As for the liquid handling instruments by Microlit, when stored for a long duration, do not need to be calibrated. Yet, it is a good lab practice to calibrate your instruments periodically.

Here is a video of how a Microlit Bottle Top Dispenser is calibrated. 

Product Storage

Storage of liquid handling instruments is just as important as cleaning and calibrating them. All the instruments and their accessories should be stored in a clean, cool and dry place. The storage place should have a temperature ranging from -20 °C to 50 °C (from -4 °F to 120 °F) with relative humidity between 5% and 95%. Another point to be remembered is that the instrument should be stored in an upright position. To store pipettes, Microlit recommends the use of its carousel stand, Microlit Faveo.

Troubleshooting

While operating an instrument, a user might face a common issue that s/he might not be aware of. In such instances, it is crucial to analyse the issue and take corrective measures. The troubleshooting measures for all instruments like pipettes, electronic burettes and bottle top dispensers, as given below, are different and should be followed to the dot. 

Shown below: Troubleshooting in Microlit Bottle Top Dispensers

ProblemPossible CauseSolution
Piston difficult to moveFormation of crystals or deposition of dirtStop dispensing immediately. Loosen the piston with a circular motion, but do not disassemble. Follow all cleaning instructions. 
Air bubbles appear in the instrumentReagent with high vapour pressure has been drawn in too quickly

The instrument has not been primed

Filling tube is loose or damaged

 

Liquid reservoir is empty


The filling action is too fast

The piston is leaking

The discharge valve is leaking

Draw the reagent slowly


Prime the instrument 

Push the filling tube on firmly. If necessary, cut off approx. 1 cm of the tube at the upper end and then reconnect it or replace it.

Refill reservoir and prime the unit


Fill and dispense slowly

Clean the piston. If the problem persists, replace it.

Clean by flushing thoroughly with distilled water

 

Dispensing is not possible

 

Dispensing nozzle is blocked


Discharge valve is stuck


Recirculation knob is rotated in the wrong direction and the knob has popped out

Disassemble the dispensing nozzle and flush thoroughly with distilled water

Clean the unit by immersing valve assembly in distilled water

Set the recirculation knob in the dispense mode and press the knob firmly to ensure it is tightly fitted 

Wrong dispensing volume

 

The volume adjustment knob is not properly locked

The instrument is not calibrated

Crack in the cylinder barrel due to an accident can cause leakage

Properly lock the volume adjustment knob


Follow user calibration steps

Do not try to repair. Contact the nearest dealer or manufacturer.

Barrel does not fill with liquid

 

Inlet tube is not fitted properlyCheck the quantity of liquid in the reagent bottle and ensure that the inlet tube is completely dipped in the liquid.
Filling not possible

 

Adjust volume to minimum settingSet to the required volume

 

 

Shown below: Troubleshooting in Microlit E-Burette

ProblemPossible CauseSolution
Piston difficult to moveFormation of crystals or deposition of dirtPerform a cleaning cycle
Filling not possibleFilling valve stuckClean the filling valve. If the valve ball is stuck, use a 200 ml plastic tip to loosen it. 
Air bubbles in the instrumentPurging not complete

Filling tube loose or damaged 

Filling tube does not dip into the liquid

Purge the instrument again

Fasten the telescopic filling tube firmly. If necessary, cut the tube off by approx. 1 cm from the top or replace it.

Fill up the bottle, or correctly adjust the length of the telescopic filling tube

The volume delivered is smaller than that indicatedThe instrument has not been completely primedPrime the instrument again
The instrument doesn’t indicate any functionInternal errorPerform a restart

 

Shown below: Troubleshooting in Microlit RBO Series Micropipettes

ProblemPossible CauseSolution
Liquid is leaking from pipette tipPipette tip does not fit properly onto the tip cone

Liquid being pipetted is hot or cold or very dense or viscous.

Tip is not loaded to maintain the seal

Use the appropriate tip for exact tip fitment


Shorten the amount of time the liquid is in the tip or use the reverse mode of pipetting

Press on the tip more firmly (avoid using too much force and over inserting the tip)

Amount of sample delivered is not accuratePipette is not within calibration specifications

Improper pipetting technique

Re-calibrate the pipette as per the Operation Manual

See suggestions for improving pipetting technique and results in the Operation Manual

Liquid handling instruments play an important role in research and tests. So, make sure that they are always in good condition. Quality assurance of the instrument assures the quality of the test. Put in place a robust quality assurance programme to keep the tests accurate and cost-effective. Even the slightest error in the instrument can lead to the whole test going south resulting in huge costs for your lab, wastage of reagents and even proving fatal for researchers.

If you have any technical query or questions related to product information & maintenance, send us an email on support@microlit.com.

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