# Pipette Storage Best Practices Proper pipette storage keeps a single-channel or multichannel air-displacement pipette accurate, uncontaminated, and mechanically sound between uses. The full routine described here takes about 2 to 5 minutes of hands-on time at the end of each working day, roughly 15 minutes for a monthly inspection, and 45 to 60 minutes for a full clean-and-verify cycle a few times per year. Elapsed time is short because nothing dries overnight or incubates. The payoff is large: a pipette that is stored dirty, wet, or under spring tension loses accuracy, corrodes, and contaminates every experiment that follows, while a pipette that follows pipette storage best practices holds its calibration interval and produces reproducible volumes. This guide covers the daily, monthly, and long-term storage routines for laboratory pipettes, the cleaning that must precede storage, the common mistakes that shorten pipette life, and how storage connects to pipetting technique and pipette calibration. ## The Principle: Why Storage Conditions Affect Volume Accuracy An air-displacement pipette works by compressing a spring-loaded piston and an air cushion. When you press the plunger to the first stop, the piston pushes a fixed volume of air out of the shaft. When you release the plunger with a tip attached, negative pressure draws liquid into the tip. Three storage-related factors disturb this system. First, spring tension. A pipette left dialed to a partial volume holds its internal springs partially compressed between sessions. Springs under constant asymmetric load relax unevenly over months, which shifts the piston travel that corresponds to each volume setting. Second, contamination and corrosion. Liquid drawn back past the tip seal carries salts, buffers, nucleases, and dyes into the nose cone and onto the piston. Overnight, that residue dries, crystallizes, and either corrodes the stainless steel piston or drags on the seal during the next stroke. Corrosion and drag both change the effective displaced volume and cause the piston to seize. Third, the tip. A tip left attached continues to wick moisture, holds the ejector spring loaded, and acts as a reservoir for aerosols and dust. The tip is the single most common source of stored pipette contamination. A related point matters for technique. Poor pipetting habits push contamination into the pipette in the first place. Studies of liquid-handling variability show that even tip handling matters. In a standardized nematode-counting protocol, the researchers tested variables across 14 separate experiments and found that shaking of the culture, priming of pipette tips, and sampling location within the tube all produced statistically significant effects on the counts, while operator skill did not [1]. If tip priming changes a routine count, residues and fluid behavior inside a used tip change what backs up into your pipette. Storage is the last line of defense after technique. ## When to Apply This Routine - **Daily**, at the end of a session that used aqueous buffers, media, or routine reagents. Empty, wipe, and hang. - **After any spill or aspiration of corrosive, volatile, radioactive, or infectious material.** Decontaminate before storage, not before the next use. - **Monthly**, a short inspection of the nose cone, seals, and ejector, plus a function check. - **Quarterly to annually**, a full disassembly-clean-lubricate cycle combined with a calibration verification, timed to your lab's calibration schedule. - **Before long-term storage**, such as putting a pipette away for a sabbatical leave, a lab closure, or a seasonal teaching bench. ## Materials and Reagents for the Storage Routine | Item | Working concentration or specification | Purpose | |--|--|--| | Ethanol in water | 70% (v/v) ethanol | Routine external decontamination of housing and nose cone | | Sodium hypochlorite solution | 10% household bleach diluted 1:10, roughly 0.5% available chlorine, freshly prepared | Decontamination after biological spills, metal parts protected or rinsed immediately | | Distilled or deionized water | Reagent grade | Rinsing after bleach or detergent contact, rinsing internal parts | | Mild laboratory detergent | Diluted per label | Removing greasy or proteinaceous residue from disassembled parts | | Silicone grease | Manufacturer-supplied piston grease only | Relubricating piston and seal O-rings during deep cleaning | | Lint-free wipes | Nonabrasive, low particulate | Wiping shafts and pistons without leaving fibers | | Pipette stand, carousel, or wall rack | Vertical, compatible with tip ejector overhang | Correct storage orientation | | Storage case with desiccant | Silica gel pack, replaced when indicator changes | Long-term storage in low humidity | | Analytical balance | Calibrated, readable to 0.1 mg for volumes of 100 µL and below | Gravimetric verification before returning a pipette to service | | Thermometer and barometer or hygrometer | Benchtop | Converting weighed mass to delivered volume during verification | | Nitrile gloves and eye protection | Standard lab PPE | Personal protection during decontamination | **Safety note.** 70% ethanol and isopropanol are flammable. Use them away from open flames, heat blocks, and Bunsen burners, and let surfaces dry before returning the pipette to a cabinet. Dilute bleach in a fume hood or well-ventilated area, never mix bleach with other cleaners, and never let bleach sit on aluminum or steel pipette parts. Bleach and other chlorine-based cleaners corrode metal shafts and pistons, so any bleach contact must be followed immediately by a thorough distilled-water rinse and complete drying. ## How to Store Pipettes Step by Step ![Five step card sequence for end of day pipette storage: eject tip, dial to top of range, wipe with ethanol, inspect nose cone, hang vertically.](/article-images/illustrations/how-to-store-pipettes-daily-storage-routine.webp) This numbered routine covers the daily storage sequence, with the reason behind each critical step. 1. **Eject the tip before anything else.** Press the ejector button while holding the pipette over a sharps or tip waste container. A left-on tip keeps the ejector spring loaded, wicks fluid back toward the seal, and collects dust in the open bore. Ejecting first also removes the most likely contamination source before you handle the body. 2. **Set the volume toward the top of the pipette's range.** For most adjustable air-displacement models, dialing near the maximum volume releases internal spring tension during storage. Check your model's manual, because a few designs state a different preferred setting. The reason is mechanical: springs held partially compressed for weeks relax unevenly and shift the volume-to-piston-travel relationship. 3. **Wipe the entire exterior with 70% ethanol on a lint-free wipe.** Pay attention to the thumb plunger, the ejector arm, the volume dial knurl, and the hand rest. Ethanol removes fingerprints, salts, and residues that would otherwise migrate into joints and crevices during storage. 4. **Inspect the nose cone and shaft.** Look for dried droplets, crystalline residue, cracks, or a deformed tip cone. Wipe the outside of the shaft with ethanol. If residue is visible inside the tip cone or fluid is suspected past the seal, do not simply store the pipette. Continue to step 5. 5. **Clean internally when contamination is suspected.** Follow your manual to remove the lower assembly, usually by unscrewing the shaft or nose cone collar. Rinse the disassembled parts with distilled water, then with ethanol if the manual permits, and air-dry fully before reassembly. Check the piston for corrosion or scratches and the seal O-ring for flattening. Relubricate with the manufacturer-supplied silicone grease only, applied sparingly. Reagent-compatible cleaning and reuse protocols exist even for demanding single-cell applications. A rapid enzymatic cleaning protocol for patch-clamp pipettes, completed in under 30 seconds, sustained a whole-cell recording success rate above 90% across more than 100 reuses of a single pipette [2]. The broader lesson transfers directly: a defined, quick cleaning routine outperforms replacement-and-forget habits. 6. **Decontaminate after biological spills before storage.** For infectious or recombinant material, wipe or rinse the affected parts with freshly diluted 10% bleach, keep contact brief, then rinse immediately with distilled water and dry. The rinse is not optional. Residual hypochlorite pits stainless pistons within days. Where the manual recommends ethanol or a proprietary decontaminant instead of bleach, follow the manual. 7. **Reassemble and perform a function check.** Attach a fresh tip, aspirate and dispense distilled water several times, and watch for smooth piston travel, a clean meniscus, and no dripping. A dripping pipette stored overnight develops internal residue by morning. 8. **Hang the pipette vertically.** Place it on a pipette stand, carousel, or wall rack, upright, with no tip attached. Vertical storage keeps any residual condensate out of the shaft, prevents the ejector arm from bearing weight, and stops the barrel from rolling off the bench. Horizontal storage in a drawer is the opposite of all three. 9. **Store in a controlled environment.** Choose a spot away from windows and ultraviolet sources, away from heat blocks, incubators, and centrifuges, and away from volatile solvent bottles. High humidity corrodes, ultraviolet light embrittles plastic, and heat degrades seals. A closed cabinet at ordinary room temperature with low dust is ideal. 10. **Attach the calibration or service tag.** Note the date of the last calibration and the next due date on the pipette or its stand slot. This turns storage into a visible record so nobody grabs an overdue pipette for a critical assay. 11. **For long-term storage, use the original case with desiccant.** Clean the pipette fully, dry it, dial it to the top of the range, place it in its case with a fresh silica gel pack, close the case, and store it upright in a dry cabinet. For transport between labs or buildings, sealed case plus desiccant also protects against pressure and moisture changes. 12. **Log the storage event if your lab tracks equipment.** A one-line entry, date, cleaning done, function check passed, is enough. The log becomes the backbone of your calibration history. ## Storage Choices That Interact With Pipetting Technique Storage does not stand alone. The way you pipette during the day determines what storage has to repair at night. **Pre-wetting and priming.** Aspirating and dispensing the working volume two or three times before the first transfer conditions the air cushion and humidifies the dead-air space, which reduces evaporation-driven error on the first dispense. The nematode-counting study cited earlier identified tip priming as one of only three variables with a significant effect on count accuracy out of everything tested, including operator identity [1]. A pipette stored with a wet or contaminated tip starts the next day with that same tip-condition problem already inside the shaft. **Avoiding over-immersion.** Immerse the tip only 2 to 3 millimeters into liquid when aspirating. Deep immersion forces fluid against the tip cone and increases the chance of carryover past the seal, which is exactly what storage cleaning then has to remove. **Releasing the plunger smoothly.** Snapping the plunger back after aspiration pushes liquid violently against the tip walls and splashes aerosols into the nose cone. Smooth release keeps the air cushion stable and keeps the pipette cleaner. **Low-volume work.** Small volumes amplify every error, mechanical and human. In an optimized plant genomic [DNA extraction protocol](/blog/guides/dna-extraction-protocol), the authors specifically specified low-volume pipetting for the dual 70% ethanol wash steps, because residual salts carryover at small volumes directly determines downstream sequencing quality [3]. If your work routinely involves sub-20 µL transfers, treat daily cleaning and vertical storage as mandatory rather than recommended, because the accuracy margin is thinner. **Automated and semiautomated workflows.** Labs that move between manual pipettes and automated sample-preparation platforms should hold stored manual pipettes to the same cleanliness standard as instrument fluidics. Protocol optimization work in mass cytometry sample preparation emphasizes that variability minimization, including how labeled samples are stored and handled, directly affects data quality [4]. A contaminated stored pipette undermines an otherwise automated workflow the same way a dirty robot probe does. ## Storage and Pipette Calibration Calibration is the process of comparing the volume a pipette actually delivers against the volume its dial reads, then correcting or adjusting the difference. Storage and calibration are linked in both directions. Good storage extends the calibration interval. A pipette kept clean, dry, upright, and tension-free drifts less between calibrations because the failure modes that cause drift, corrosion, seal compression set, and spring relaxation, are all storage-dependent. Bad storage causes calibration failures. The classic pattern is a pipette that passes calibration, then sits in a drawer for two months with a tip attached and a puddle of saline in the nose cone. When it fails its next gravimetric check, the cause is not wear but preventable storage damage. A sensible interim check between formal calibrations is a simple gravimetric test on a calibrated analytical balance. As a worked example, set a 100 µL pipette to 100 µL, pre-wet the tip, dispense distilled water into a weighed vessel ten times, and record each mass. At standard [laboratory conditions](/knowledge/diagnostics/molecular/laboratory-conditions), 100 µL of water weighs approximately 100 milligrams, so each dispense should read near 0.1000 g. Calculate the mean and the [coefficient of variation](/blog/research-skills/how-to-calculate-coefficient-of-variation). Compare your mean to the manufacturer's nominal error limits printed in the manual, which for most mid-range pipettes fall around plus or minus 1% of the nominal volume, and compare your scatter to the stated repeatability limit. Formal verification follows the weighing procedure and environmental corrections described in the ISO 8655 standard family for piston-operated volumetric apparatus, which is the reference most calibration services use. If the pipette is out of limits, adjust it if the model allows, then retest. If it cannot hold limits after adjustment, send it for professional service rather than storing a bad instrument back on the rack. **Expected results after a correct storage routine.** A well-stored pipette shows a clean, dry, smooth nose cone, free piston travel with a soft and consistent plunger feel, no dripping when held tip-down with a fresh tip and water loaded, and gravimetric performance inside the manufacturer's limits. **Reading your results.** If the balance readings drift upward across the ten dispenses, suspect evaporation from the weigh vessel and add a lid or evaporation trap. If the mean is consistently low, suspect a leaking seal or an incompletely seated tip. If the scatter is high, suspect technique, a damaged tip cone, or piston drag from residue. ## Troubleshooting Storage-Related Pipette Problems ![Three question triage path for pipette cleaning: spill of corrosive or infectious material, residue inside the tip cone, or a routine aqueous session.](/article-images/illustrations/how-to-store-pipettes-contamination-triage.webp) | Symptom | Likely cause | Fix | |--|--|--| | Pipette drips when loaded and held tip-down | Tip not seated, cracked tip cone, seal failure, or internal residue on the piston | Re-seat or replace the tip, inspect the cone, clean internally and relubricate the seal | | Volume reads inconsistently across replicate dispenses | Piston drag from dried residue, worn seal O-ring, or spring relaxation from improper long-term storage | Deep clean, replace the seal per manual, recalibrate | | Plunger feels stiff or gritty | Salt crystallization or corrosion on the piston, lost lubrication | Disassemble, inspect for pitting, clean, apply manufacturer grease. Replace the piston if pitted | | Ejector sticks or fails to release tips | Spring under sustained load from a tip left attached, or dried media in the ejector channel | Clean the ejector channel, replace the ejector spring per manual, never store with a tip attached | | Visible condensation or fluid inside the shaft | Aspiration of volatile or foaming liquid, or storage with a wet tip | Disassemble and dry completely, review immersion depth and pipetting technique | | White crystalline deposits around the nose cone | Buffer salts wicked past the tip seal | Clean with distilled water followed by ethanol, then dry. Check tip fit | | Calibration fails shortly after passing | Storage under partial spring compression, horizontal storage, or heat and humidity exposure | Correct the storage routine, service the pipette, and shorten the interim-check interval | | Musty smell or cloudy film inside a long-stored pipette case | Humidity ingress, exhausted desiccant | Replace desiccant, dry the pipette fully, re-store sealed | | Autofoclaveable pipette leaks after autoclaving | Stored wet before autoclaving, or reassembled before fully dry | Autoclave per manual, cool, and dry completely before storage. Replace seal if deformed | ## Variations by Pipette Type **Electronic pipettes.** Follow the manual's battery guidance before storage. Most models should be stored with the battery either fully charged or removed, depending on the design, and never stored with a depleted battery installed, because discharged cells leak and destroy contact terminals. Power the unit down, eject the tip, wipe, and hang vertically as for mechanical models. **Multichannel pipettes.** Clean each channel. A single contaminated channel defeats a daily wipe-down of the others. Check that every ejector finger moves freely. Store multichannel instruments on a stand wide enough to support the head, since the overhanging head makes them unstable lying flat. **Positive-displacement pipettes.** These use a plunger-tipped capillary that contacts liquid directly. Remove the capillary and piston assembly before storage, cap the piston in its storage vial, and never leave a capillary mounted, because sample residue dries onto the piston and ruins the seal. **Repeater and dispenser pipettes.** Empty the reservoir or combi-tube completely, disassemble the dispensing head if the manual instructs it, and store the unit with all valves dry. Residual reagent in a stored valve is the leading cause of sticky dispensers. **Pipettes awaiting repair or disposal.** Decontaminate and label any pipette leaving active service, especially if it carried biological or radioactive material, before it goes to a service center or a waste stream. ## Storage and Stability Notes - **Orientation.** Vertical, always. A stand or wall rack costs less than one recalibration. - **Environment.** Ordinary room temperature, low humidity, no direct sun, no ultraviolet cabinet exposure, no proximity to ovens, heat blocks, centrifuges, or solvent shelves. - **Duration.** Daily storage on a rack indefinitely. Long-term storage in the original case with fresh desiccant. Before returning a pipette from long-term storage, inspect the seals, run a function check with distilled water, and perform a quick gravimetric spot check if the pipette will be used for quantitative work. - **After autoclaving.** Only autoclave pipettes and parts the manual lists as autoclaveable, typically 121 °C for the stated cycle time in the manual. Cool to room temperature and dry completely before reassembly and storage. Storing a warm, damp pipette in a closed case traps condensation against the piston. - **Shared benches.** In multi-user labs, assign rack slots and let the calibration tags do the talking. A visible due-date tag prevents silent rotation of overdue pipettes into critical assays. ## Common Mistakes and Limitations These are the pipette storage mistakes seen most often, and what they cost. - **Storing with a tip attached.** The most frequent mistake. It keeps the ejector spring loaded, wicks fluid into the seal, and invites contamination. - **Storing horizontally in a drawer.** Residual liquid runs into the shaft, the barrel rolls, dust settles in the open cone, and calibration tags face the wrong way. - **Storing dirty because "I will clean it before I use it."** Dried buffer salts and media are far harder to remove the next week than the next hour. Storage cleaning is part of the experiment, not an extra. - **Letting bleach stand on metal parts.** Chloride corrosion of a piston is permanent. Bleach contact must be brief and followed by a water rinse. - **Autoclaving parts the manual excludes.** Non-autoclaveable housings warp and seals deform, and the damage shows up as a calibration failure weeks later. - **Storing pipettes dialed to minimum volume for years.** On most models this holds springs near maximum compression. Dial to the top of the range unless your manual says otherwise. - **Ignoring the environment.** A windowsill rack, a spot above a heat block, or a shelf above a solvent bath all shorten pipette life. - **Skipping the pre-storage function check.** A problem discovered at storage is fixed in five minutes. The same problem discovered mid-assay costs a day of repeats. - **Treating storage as a substitute for calibration.** Storage protects calibration, it does not replace it. Formal gravimetric calibration on the schedule your lab defines remains the only proof of accuracy. - **One limitation worth stating plainly.** Every pipette model differs in spring design, seal material, autoclave tolerance, and preferred storage setting, so the model manual always overrides generic advice, and individual instruments with unusual service histories need evaluation by a qualified service technician rather than a generic routine. ## Frequently Asked Questions ### Should I leave a tip on my pipette when storing it? No. Eject the tip before storage every time. A left-on tip keeps the ejector spring loaded, wicks moisture and contaminants toward the tip seal, and collects dust in the open cone, which is how internal corrosion and cross-contamination start. ### What volume setting should a pipette be dialed to for storage? For most adjustable air-displacement pipettes, dial to the top of the volume range before storage so the internal springs are not held under partial compression. Verify the recommendation in your specific model's manual, because a few designs specify something different. ### Is vertical or horizontal storage better for pipettes? Vertical storage on a stand or wall rack is better in every case. It keeps residual moisture out of the shaft, prevents barrel rolling, keeps dust out of the nose cone, and leaves calibration tags visible. ### How often should a pipette be calibrated? Follow your lab's written schedule, which in most research settings falls between every 6 and 12 months of service, with shorter intervals for high-use or critical-assay pipettes. Between formal calibrations, a simple gravimetric spot check on a calibrated analytical balance catches drift early. ### Can I autoclave my pipette before long-term storage? Only if the manual lists the pipette or the specific lower parts as autoclaveable, typically at 121 °C. After the cycle, let it cool and dry completely before reassembly and storage, because storing a damp pipette sealed in a case traps condensation against the piston. ### How do I store a pipette I will not use for several months? Clean it thoroughly, dry it completely, dial it to the top of the range, place it in its original case with a fresh desiccant pack, close the case, and store it upright in a dry cabinet. When it comes back into service, inspect the seals, run a function check with distilled water, and verify volume gravimetrically before critical use. ### Does storage really affect pipette accuracy? Yes. Spring relaxation from long storage under compression, seal deformation, piston corrosion from dried residues, and ejector spring fatigue are all storage-driven failure modes that change delivered volume. Correct storage is the cheapest way to extend both accuracy and calibration intervals. ### How should I handle pipettes between uses within a single day? Eject the tip, wipe the exterior if there was any splash risk, and return the pipette to its vertical stand between sessions. Full internal cleaning is reserved for spills, contamination events, or the end of the day, not for every trip to the reagent shelf. ## Further Reading - [A New Store-Then-Amplify-and-Forward Protocol for UAV Mobile Relaying](https://doi.org/10.1109/LWC.2019.2961668) - [IRPanet: Intelligent Routing Protocol in VANET for Dynamic Route Optimization](https://doi.org/10.14569/IJACSA.2019.0100657) ## Sources 1. [Counting Caenorhabditis elegans: Protocol Optimization and Applications for Population Growth and Toxicity Studies in Liquid Medium](https://pubmed.ncbi.nlm.nih.gov/29343752/) 2. [Method for Rapid Enzymatic Cleaning for Reuse of Patch Clamp Pipettes: Increasing Throughput by Eliminating Manual Pipette Replacement between Patch Clamp Attempts.](https://pubmed.ncbi.nlm.nih.gov/34395724/) 3. [Optimization of CTAB Based Plant Genomic DNA Extraction Protocol for Genotyping by Sequencing](https://doi.org/10.9734/jabb/2026/v29i74143) 4. [Automation of sample preparation for mass cytometry barcoding in support of clinical research: protocol optimization](https://pubmed.ncbi.nlm.nih.gov/28124752/)