Burette, Rotaflow

Quick Answer: A Rotaflow burette is a graduated glass burette fitted with a screw-action valve: a PTFE spindle turns in a threaded glass body to open or close the flow. The valve gives very fine control, down to part-drops, and needs no grease.

A Screw Valve Instead of a Turning Plug

Most burettes control flow with a tapered plug turned through a quarter turn between open and closed. The Rotaflow pattern works differently. Its glass valve body is threaded, and a PTFE spindle with a sealing tip screws into it; turning the knob advances or withdraws the tip from a seat, so the opening grows gradually over several turns. That gradual opening is what lets titrant be released in a steady trickle, in single drops or in fractions of a drop.

Fine control is most useful in titrations whose end point is gradual or easy to overshoot. In an EDTA titration for water hardness, Eriochrome Black T changes from wine red to blue only slowly near the end, and in an iodine-thiosulfate titration the last blue of starch must be discharged by the final drop. With a Rotaflow burette the analyst can add part-drops and rinse them in from the tip with a wash bottle.

Because nothing in the valve is greased, there is no film to contaminate the titrant or block the tip, and alkaline solutions do not seize it. The valve can be opened fully for fast filling and draining of cleaning water. Capacity and graduation interval are not stated in the listing.

Applications

EDTA complexometric titrations for calcium and magnesium hardness in water
Iodometric titrations with sodium thiosulfate and starch indicator
Accurate acid-base work where part-drop additions sharpen the end point
Titrations with alkaline titrants that would seize a glass stopcock

Specifications

Item	Graduated burette with screw-action (Rotaflow-pattern) valve
Valve	PTFE spindle in a threaded glass body; greaseless
Control	Gradual opening over several turns for drop and part-drop delivery
Suited titrations	Gradual or sharp end points: complexometric, iodometric, acid-base
Capacity and graduation	Confirm at enquiry

Care & Handling

Close the valve with light finger pressure only; screwing the spindle hard onto its seat deforms the PTFE tip and causes leaks.
Back the spindle out slightly before storage so the tip is not held compressed against the seat.
When cleaning, unscrew the spindle completely and rinse the thread, where fine particles collect.
Replace a spindle with a cut or flattened tip rather than tightening harder to stop a drip.

Why Choose LabEquip

Analytical chemistry and water-testing laboratories prefer the Rotaflow burette for demanding titrations in which a single drop decides the result. LabEquip lists it in the chemistry lab equipment range; share the capacity and number required via the LabEquip contact page.

Frequently Asked Questions

How does a Rotaflow valve differ from a PTFE key stopcock?

A PTFE key stopcock is a tapered plug turned through a quarter turn from closed to fully open. A Rotaflow valve is a screw: several turns take it from closed to open, so the flow changes gradually and very small amounts can be delivered.

How do I add half a drop?

Open the valve just enough for a drop to form on the tip, close it, then touch the tip against the inside wall of the flask and rinse the liquid down with a little distilled water from a wash bottle.

Why does the valve drip even when closed?

The PTFE tip may be worn, scratched or dirty, or a particle may be caught on the seat. Clean the spindle and seat, and replace the spindle if the tip is damaged; do not overtighten to stop the drip.

Does a Rotaflow burette need grease?

No. The PTFE spindle seals against the glass without lubricant, which keeps grease out of the bore and tip and avoids contaminating the delivered liquid.

Is it slower to use than a standard burette?

Opening takes a few turns rather than a quarter turn, so the start of a titration can take slightly longer. Most users run in the bulk of the titrant quickly and then use the fine control near the end point.

Can the burette be used with strong alkalis?

Yes. The valve does not depend on a ground glass joint, so alkaline solutions do not cause seizing. Rinse the burette with distilled water after use, as alkali left in contact with glass for long periods slowly etches it.

Last Updated: September 2026

Burette, PTFE Key

Quick Answer: A PTFE key burette is a graduated glass burette whose stopcock plug is made of PTFE instead of glass. PTFE needs no grease and does not seize, so the burette suits alkaline titrants and routine titrations without stopcock maintenance.

Why a PTFE Plug Replaces Glass

The stopcock is the part of a burette that gives the most trouble. A glass key must be greased to turn smoothly and seal, the grease can creep into the bore and tip, and alkali solutions can cement a glass key in its barrel. A PTFE key burette avoids these problems because PTFE (polytetrafluoroethylene) is slippery, resists almost all laboratory reagents and does not bond to glass, so the key turns freely without lubricant.

The key is usually held in the glass barrel by a threaded nut and washer on its narrow end. Tightening the nut presses the tapered plug into the barrel to stop leaks; loosening it lets the key turn more easily and allows it to be removed for cleaning. PTFE is softer than glass and can slowly cold-flow, so the tension may need a small adjustment from time to time.

This makes the PTFE key burette the practical choice for sodium hydroxide titrant, for student benches where grease tends to be over-applied, and for titrations in which grease would contaminate the delivered liquid.

Care & Handling

Do not overtighten the retaining nut; a key clamped too hard is stiff to turn and can crack the barrel.
Remove the key before drying the burette in an oven, because PTFE and glass expand differently and the key may loosen or distort.
Wash the key and barrel separately and check the bore for particles that would block delivery.
Store burettes vertically in a burette stand or flat in a padded drawer, never leaning where they can roll.

Applications

Acid-base titrations with sodium hydroxide titrant, which would seize a glass key
Student titration practicals where no stopcock grease is wanted
Non-aqueous titrations in organic solvents, which dissolve stopcock grease
Redox titrations with potassium permanganate or iodine, which rule out rubber-tube burettes

Specifications

Item	Graduated burette with PTFE stopcock key
Key material	PTFE (polytetrafluoroethylene), used without grease
Key retention	Nut and washer on the key end, as usual for this design
Suited titrants	Acids, alkalis, and most aqueous and non-aqueous reagents
Capacity and graduation	Confirm at enquiry

Why Choose LabEquip

College chemistry departments, pharmacy laboratories and schools replacing seized glass-key burettes often switch to PTFE keys. LabEquip lists this burette alongside the straight bore glass key burette in its chemistry lab equipment range; send sizes and quantities through the contact page.

Frequently Asked Questions

Does a PTFE key burette need stopcock grease?

No. PTFE is naturally slippery and seals against the glass barrel without lubricant. Adding grease is unnecessary and can make the key slide out of position or contaminate the tip.

Why is a PTFE key better for sodium hydroxide?

Alkali solutions slowly attack glass and, when they dry in a ground glass joint, can fuse a glass key to its barrel. PTFE does not bond with glass or react with alkali, so the key stays free even if some solution is left in the burette.

My PTFE key is leaking. What should I do?

Check that the washer and nut are in place and tighten the nut a little at a time until the leak stops while the key still turns smoothly. If it still leaks, look for scratches on the key or particles trapped in the barrel.

Can the key be taken out for cleaning?

Yes. Unscrew the nut, remove the washer and draw the key out of the barrel. Wash both parts, keep the small pieces together, and refit them before the burette is next used.

Is a PTFE key suitable for organic solvents?

PTFE resists almost all common solvents, so it is often chosen for non-aqueous titrations where grease on a glass key would dissolve into the titrant. Check that any plastic nut or washer also resists the solvent used.

How do I read the burette accurately?

Clamp it vertically, bring your eye level with the bottom of the meniscus and read against the graduations, estimating between the smallest marks. A white card with a black strip held behind the burette makes the meniscus sharper.

Last Updated: September 2026

Burette, Automatic Zero

Quick Answer: An automatic zero burette is a titration burette that fills from an attached reservoir and sets its liquid level to the zero mark by itself, with excess liquid overflowing back. It removes the manual step of adjusting the meniscus to zero before each titration.

How the Zero Sets Itself

In the usual design, the automatic zero burette is mounted on top of a reservoir bottle holding the titrant. Squeezing a rubber hand bellows pushes titrant up through a filling tube until it rises past the zero mark; when the pressure is released, the liquid above zero drains back through an overflow tip, leaving the meniscus exactly at zero. The titration then proceeds through a stopcock at the lower end, as with an ordinary burette.

The arrangement saves the most time where one titrant is used many times in a session: routine alkalinity or hardness checks in a water laboratory, quality-control titrations in a factory laboratory, or a class running repeated trials. Keeping the titrant in a closed reservoir also protects it, and a soda-lime guard tube on the air inlet stops sodium hydroxide solution from absorbing carbon dioxide.

The stopcock type, capacity and graduation interval are not given in the title. They should be confirmed when ordering, together with whether the reservoir bottle and bellows come as part of the set.

Specifications

Item	Burette with automatic zero-setting overflow
Filling	From a reservoir, usually by hand bellows
Zero setting	Excess liquid drains back through an overflow tip
Delivery	Stopcock at the lower end, as on a standard burette
Protective fitting	Guard tube on the air inlet is common for carbon-dioxide-sensitive titrants
Capacity, graduation and reservoir size	Confirm at enquiry

Care & Handling

Refill the reservoir only with the same standardised solution; mixing old and new batches changes the concentration.
Restandardise the titrant in the reservoir at regular intervals, because solutions drift over time.
Move the burette and reservoir as one assembly, supporting the reservoir from beneath.
Drain and rinse the whole system with distilled water before changing to a different titrant.

Applications

Repeated acid-base titrations with one standard solution through a whole practical session
Routine water-testing titrations such as total hardness or alkalinity
Quality-control titrations in which many samples are analysed with the same reagent
Storing and dispensing sodium hydroxide titrant protected from air

Why Choose LabEquip

Water-testing laboratories, college analytical labs and industrial QC rooms choose automatic zero burettes when they titrate many samples a day with one reagent. LabEquip lists it with conventional burettes such as the PTFE key burette in the chemistry lab equipment range; send your required capacity through the contact page.

Frequently Asked Questions

How is an automatic zero burette different from an ordinary burette?

An ordinary burette is filled from the top with a funnel and the meniscus is brought to zero by hand. An automatic zero burette fills from a reservoir and overflows to the zero mark by itself, so each titration starts from the same point without manual adjustment.

Does automatic zeroing make the titration more accurate?

It removes one reading error, the initial zero setting, and makes the starting point consistent between titrations. The final reading is still taken by eye at the bottom of the meniscus, so good reading technique is still needed.

Why fit a guard tube to the reservoir?

As liquid is withdrawn, air enters the reservoir. With sodium hydroxide or barium hydroxide solutions, carbon dioxide in that air slowly converts some of the alkali to carbonate. A soda-lime guard tube on the air inlet absorbs the carbon dioxide.

Can volatile or light-sensitive titrants be used?

Volatile solvents are poorly suited, because vapour builds up in the reservoir and upsets the filling. Light-sensitive titrants such as silver nitrate can be used if the reservoir is amber or shielded from light.

How do I remove an air bubble from the tip?

Open the stopcock fully for a moment with a beaker underneath so the rush of liquid carries the bubble out, then refill to zero. A bubble left in the tip gives a falsely high titre when it escapes during the titration.

What should be checked before the first titration of the day?

Check that the overflow tip is clear, that the stopcock does not leak, and that the reservoir holds enough standardised solution for the session. Run one filling cycle to waste to flush the tubes with fresh titrant.

Last Updated: September 2026

Woulf Bottle (Clear Glass)

Quick Answer: The Woulf Bottle (Clear Glass) is a multi-necked glass safety and gas-washing bottle made from clear soda-lime or borosilicate glass so the liquid level and clarity inside can be seen at a glance. It is used as a vacuum-line trap and for gas washing where visual monitoring of the liquid is helpful.

Description

This Clear Glass Woulf Bottle from LabEquip is made with two or three necks fitted with ground-glass joints, allowing separate tubes to be passed into the vessel at the same time. Being in clear glass, the bottle lets the operator see the liquid level, colour change, or any bubbling activity directly, which is useful in teaching demonstrations and routine gas-washing work where a visual check adds confidence to the procedure.

Like its amber or standard borosilicate counterpart, the clear glass version is commonly placed in-line on a vacuum filtration or distillation set-up as a safety trap, protecting the vacuum pump from any liquid that is inadvertently drawn back through the line. It is equally suited to bubbling a gas stream through a liquid reagent for washing or absorption.

The clear glass construction is chemically resistant to common laboratory reagents and offers good resistance to thermal shock. These bottles are supplied in a range of standard laboratory capacities and neck configurations — confirm the exact volume and configuration required for your set-up at the time of enquiry.

Specifications

Product Type	Woulf Bottle, Clear Glass (multi-neck safety / gas-washing bottle)
Material	Clear laboratory glass
Neck Configuration	Two or three necks with interchangeable ground-glass joints
Capacity	Supplied in a range of standard laboratory capacities — confirm exact volume at enquiry
Typical Use	Vacuum safety trap, gas washing, and visual monitoring of liquid contents
Common Settings	Teaching laboratories, demonstration set-ups, chemistry practicals

Applications

Vacuum-line safety trap where visual confirmation of liquid capture is useful
Gas washing and absorption demonstrations where students need to observe the liquid
Teaching laboratory set-ups where clarity of the vessel aids explanation
General multi-tube liquid handling with separate inlet and outlet paths
Protecting vacuum pumps and lines from liquid carry-over

Care & Handling

Check ground-glass joints for chips or cracks before each use, particularly when the bottle will be used under vacuum.
Lightly lubricate ground joints used regularly under vacuum to help maintain an airtight seal.
Clean with a suitable laboratory detergent and rinse thoroughly, taking care to clear residue from all necks.
Avoid using glassware with visible star-cracks or chips under any vacuum or pressure application.
Store upright in a dry cabinet, with neck openings protected from dust and accidental impact.

Why Choose LabEquip

LabEquip supplies clear glass Woulf bottles alongside a wide range of lab glassware and chemistry lab equipment for schools, colleges, and industrial laboratories. Our team can help you confirm the right neck configuration and capacity for your application. For bulk orders, institutional procurement, or technical questions about this product, please contact us and our team will assist promptly.

Frequently Asked Questions

What is the Clear Glass Woulf Bottle used for?

It is used as a safety trap on a vacuum line and for gas washing, where a gas stream is bubbled through a liquid reagent. The clear glass lets you see the liquid level and any activity inside the bottle.

How is the clear glass version different from a standard Woulf bottle?

The main difference is visibility: the clear glass construction allows you to observe the liquid inside directly, which is helpful for teaching demonstrations and for visually confirming liquid capture during vacuum work.

Can this bottle be used under vacuum?

Yes, provided the glassware is inspected beforehand and is free of chips, cracks, or star-fractures, it can be used as an in-line safety trap on a vacuum filtration or distillation set-up.

How many necks does the bottle have?

It is typically supplied with two or three necks fitted with ground-glass joints, allowing separate tubes for gas or liquid inlet and outlet to be used at the same time.

What capacity does the Clear Glass Woulf Bottle come in?

These bottles are supplied in a range of standard laboratory capacities and neck configurations. Please confirm the exact volume and number of necks you require when you enquire.

How should this bottle be cleaned and stored?

Clean it with a suitable laboratory detergent, rinse thoroughly, and dry before storage. Keep ground-glass joints lightly lubricated if used often, and store the bottle upright in a dry cabinet away from impact.

Last Updated: September 2026

Woulf Bottle

Quick Answer: A Woulf Bottle is a multi-necked borosilicate glass vessel used in the laboratory as a safety trap between a vacuum source and the apparatus being evacuated, and for gas washing or bubbling gas through a liquid. The extra necks allow separate tubes for gas inlet, gas outlet, and liquid access.

Description

The Woulf Bottle from LabEquip is blown from borosilicate 3.3 glass and features two or three necks fitted with interchangeable ground-glass joints. This multi-neck design lets the user pass separate glass or PTFE tubes through the bottle at the same time — commonly one tube reaching below the liquid surface for gas delivery and another remaining above the liquid for gas exit or pressure release.

Woulf bottles are most often used as a safety or “trap” bottle placed in-line on a vacuum filtration or vacuum distillation set-up, where they catch any liquid that might otherwise be drawn back into the vacuum pump, protecting both the pump and the experiment. They are equally suited to gas washing and gas absorption work, where a gas stream is bubbled through a liquid reagent held in the bottle.

Because the body is thick-walled borosilicate glass, the bottle can safely be used under reduced pressure (vacuum) as part of a trap train, and it resists thermal shock and attack from common laboratory chemicals. These bottles are supplied in a range of standard laboratory capacities — confirm the exact volume and neck configuration required for your set-up at the time of enquiry.

Specifications

Product Type	Woulf Bottle (multi-neck safety / gas-washing bottle)
Material	Borosilicate 3.3 glass
Neck Configuration	Two or three necks with interchangeable ground-glass joints
Capacity	Supplied in a range of standard laboratory capacities — confirm exact volume at enquiry
Typical Use	Vacuum safety trap, gas washing, and gas absorption
Common Settings	Chemistry laboratories, vacuum filtration and distillation set-ups, teaching labs

Applications

In-line safety trap between a vacuum pump and filtration or distillation apparatus
Gas washing and purification, bubbling a gas stream through a liquid reagent
Gas absorption experiments in chemistry teaching laboratories
General multi-tube liquid handling where separate inlet and outlet paths are needed
Protecting vacuum lines and pumps from liquid carry-over during evacuation

Care & Handling

Inspect the ground-glass joints for chips or cracks before each use under vacuum, since a damaged joint can compromise the seal.
Apply a light film of an appropriate lubricant to ground joints if they are used regularly under vacuum, to maintain an airtight seal and prevent sticking.
Clean thoroughly with a suitable laboratory detergent and rinse well, ensuring all necks and tubes are free of residue.
Never exceed the safe vacuum rating of the glassware or use a bottle with visible star-cracks or chips under vacuum.
Store upright in a dry cabinet with the neck openings protected from dust and impact.

Why Choose LabEquip

LabEquip supplies Woulf bottles and other specialist lab glassware alongside a wider range of chemistry lab equipment for schools, colleges, and industrial laboratories. Our team can help you confirm the right neck configuration and capacity for your vacuum or gas-handling set-up. For bulk orders, institutional procurement, or technical questions about this product, please contact us and our team will assist promptly.

Frequently Asked Questions

What is a Woulf bottle used for?

A Woulf bottle is typically used as a safety trap on a vacuum line, to catch liquid before it reaches the pump, and for gas washing, where a gas stream is bubbled through a liquid held in the bottle.

Why does a Woulf bottle have more than one neck?

The extra necks allow separate tubes to pass into the bottle at the same time, so one tube can carry gas or liquid in while another provides an outlet or connects to the vacuum line, without the tubes interfering with each other.

Can a Woulf bottle be used under vacuum?

Yes, Woulf bottles are commonly used under reduced pressure as part of a vacuum filtration or distillation set-up, provided the glassware is inspected beforehand and is free of chips, cracks, or star-fractures.

What material is the Woulf bottle made from?

It is made from borosilicate 3.3 glass, which offers good chemical resistance and resistance to thermal shock, both of which are important for reliable use in vacuum and gas-handling applications.

What capacity does the Woulf bottle come in?

These bottles are supplied in a range of standard laboratory capacities and neck configurations. Please confirm the exact volume and number of necks you need when you enquire, and our team will help you select the right option.

How should a Woulf bottle be maintained?

Keep the ground-glass joints clean and lightly lubricated if used often under vacuum, clean the bottle thoroughly after use, inspect regularly for damage, and store it upright in a dry cabinet away from impact.

Last Updated: September 2026

Weighing Bottle

Quick Answer: LabEquip’s Weighing Bottle is a chemically inert borosilicate glass vessel with a close-fitting lid, purpose-built for accurately weighing hygroscopic or volatile substances on an analytical balance without the sample absorbing atmospheric moisture or evaporating during the process.

Product Description

Weighing Bottles are small laboratory vessels engineered specifically for the measurement of hygroscopic or volatile substances. Constructed from chemically inert borosilicate glass, they help prevent atmospheric moisture absorption or sample evaporation during the analytical weighing process, supporting pharmaceutical quality control and quantitative analysis where sample mass integrity is critical from the moment a substance is weighed to the moment it is used.

What Makes This Instrument Distinct

Unlike LabEquip’s measuring cylinders, which are designed for measuring liquid volume, the Weighing Bottle is built for accurately weighing solid or liquid samples by mass. Its close-fitting lid is the key feature: it lets the sample be weighed, transferred, and re-weighed with minimal exposure to ambient air, which matters for substances that would otherwise gain or lose mass through moisture absorption or evaporation between weighings — a common requirement in loss-on-drying and moisture-content determinations.

Specifications

Attribute	Detail
Material	Chemically inert borosilicate glass
Lid	Close-fitting ground-glass lid to limit air exposure
Function	Accurate weighing of hygroscopic or volatile substances on an analytical balance
Typical Use	Pharmaceutical quality control, quantitative analysis, moisture-content determination
Exact Dimensions & Capacity	Confirm with our sales team for your required size

Care & Maintenance

Clean and dry the bottle thoroughly before use, since any residual moisture will affect weighing accuracy.
Handle with clean, dry tongs or gloves rather than bare hands, as fingerprints add mass and moisture to the bottle.
Keep the lid on whenever the bottle is not being actively weighed into or out of, to minimise exposure to ambient moisture.
Store in a clean, dry environment, ideally in a desiccator between uses for moisture-sensitive applications.

Why Choose LabEquip

LabEquip supplies weighing and measuring instruments that work together across a lab’s analytical workflow, from precise reference masses to purpose-built vessels for handling sensitive samples. Explore related instruments:

Frequently Asked Questions

What is a Weighing Bottle used for?
It is used to accurately weigh hygroscopic or volatile substances on an analytical balance, minimising moisture absorption or evaporation during the process.

How is this different from a measuring cylinder?
A measuring cylinder measures liquid volume, while a Weighing Bottle is designed to weigh a sample by mass with minimal exposure to ambient air.

Why does the lid matter?
The close-fitting lid limits how much the sample’s mass can change from moisture absorption or evaporation between weighings, which is important for hygroscopic or volatile substances.

What material is the Weighing Bottle made from?
Chemically inert borosilicate glass, chosen for its resistance to most laboratory reagents and stable behaviour during weighing.

What sizes are available?
Exact dimensions and capacity vary; please confirm your requirement with our sales team.

How should I care for a Weighing Bottle?
Keep it clean and dry, handle it with tongs or gloves rather than bare hands, and store it with the lid on, ideally in a desiccator between uses.

Last Updated: September 2026

Wash Bottle

Quick Answer: A laboratory wash bottle is a bottle fitted with a delivery tube and jet, used to direct a fine stream of distilled water or another rinsing liquid onto glassware, precipitates or filter paper. It lets a chemist rinse exactly where needed without pouring.

Directing a Rinse Where It Is Needed

Quantitative work depends on rinsing. When a precipitate is transferred to a filter, the last particles clinging to the beaker must be washed across; when a solution is moved to a volumetric flask, the beaker and funnel are rinsed into it; and during a titration the walls of the conical flask are rinsed so that splashed titrant can react. A laboratory wash bottle does all of these with a thin jet that can be aimed and stopped at once.

Two designs are in use. The common modern form is a squeeze bottle of flexible plastic, usually polyethylene, where pressing the sides forces liquid up the tube. The older glass form is a flask with two tubes through its stopper, in which the user blows into one tube to drive liquid out of the other; blowing by mouth is discouraged today. The listing does not say which design or material is supplied, so confirm this when ordering.

Wash bottles are normally kept for one liquid each, most often distilled or deionised water, with separate, clearly labelled bottles for ethanol or propanone, since a jet of the wrong solvent can dissolve a product or ruin a precipitate.

Specifications

Item	Rinse bottle with delivery tube and jet
Operation	Squeeze or blow-type delivery, depending on the design supplied
Typical liquids	Distilled or deionised water; labelled solvent bottles for ethanol or propanone
Main uses	Rinsing precipitates, glassware and transfer steps
Design, material and capacity	Confirm at enquiry

Applications

Washing a precipitate such as barium sulfate or silver chloride on filter paper during gravimetric analysis
Rinsing the walls of the titration flask and the tip of the burette near the end point
Quantitative transfer of a solution from beaker to volumetric flask
Rinsing electrodes, such as a pH electrode, between measurements

Care & Handling

Label every wash bottle with its contents and fill it only with that liquid.
Point the jet into the vessel and away from people; a squeeze bottle gripped hard can spray unexpectedly.
Keep the jet tip clean and unblocked, since a partly blocked tip gives an erratic spray.
Empty and refill water bottles regularly rather than topping them up, so the water stays clean.

Why Choose LabEquip

Every titration bench and gravimetric practical needs at least one wash bottle, so schools and colleges usually order them by the dozen. LabEquip lists this item in its chemistry lab equipment range; send the design, size and quantity you want through the contact page.

Frequently Asked Questions

Why use a wash bottle instead of pouring from a beaker?

A wash bottle gives a thin, aimable jet that uses very little liquid and can be stopped instantly. That control matters when rinsing a precipitate or making a solution up to volume, where excess liquid would spoil the result.

Should I use tap water or distilled water in a wash bottle?

Use distilled or deionised water for analytical work, because tap water contains dissolved ions such as chloride and calcium that can react with or contaminate the sample. Tap water is fine only for the first rinse of dirty glassware.

Can a wash bottle hold acetone or ethanol?

Yes, if the bottle material resists the solvent and the bottle is clearly labelled. Keep solvent wash bottles away from flames and hot plates, because the jet can spray flammable liquid.

How do I wash a precipitate on a filter paper?

Direct a gentle stream around the upper edge of the filter paper so the liquid runs down and carries the solid into the cone. Several small washings, each allowed to drain, remove impurities better than one large washing.

Why does my plastic wash bottle keep dripping?

Warmth makes the air and vapour inside expand and push liquid out of the jet, especially with volatile solvents. Keep the bottle away from heat, and briefly loosen the cap to release the pressure before use.

How often should the wash bottle be cleaned?

Empty and rinse it at least weekly, or whenever the water looks cloudy or the tube has deposits. Algae and bacteria can grow in water left standing for long periods, especially in warm, bright rooms.

Last Updated: September 2026

Relative Density Bottle (Specific Gravity Bottle)

Quick Answer: A Relative Density Bottle, also called a Specific Gravity Bottle or pyknometer, is a precision-ground borosilicate glass vessel used to measure the density and relative density (specific gravity) of liquids by comparing the weight of a fixed volume of sample against an equal volume of water. It is a standard item in chemistry, pharmaceutical, and quality-control laboratories.

Description

The Relative Density Bottle from LabEquip is manufactured from chemically resistant borosilicate 3.3 glass and fitted with a close-fitting, interchangeable ground-glass stopper that carries a fine capillary bore. This capillary allows excess liquid to escape when the stopper is inserted, ensuring the vessel is filled to a precisely repeatable internal volume every time it is used — the key requirement for accurate relative density determination. The stopper is individually ground to its own bottle, so each unit is matched as a set and should not be interchanged with stoppers from other bottles.

In use, the bottle is weighed empty, then filled with distilled water and weighed again, and finally filled with the test liquid and weighed a third time. Comparing these readings gives the relative density of the sample against water at a stated temperature. Because the glass is dimensionally stable and resistant to thermal shock, results remain consistent across repeated determinations, which is essential for pharmacopoeial and industrial testing protocols.

These bottles are supplied in a range of standard laboratory capacities to suit different sample sizes and testing methods — confirm the exact volume required for your application at the time of enquiry.

Specifications

Product Type	Relative Density Bottle / Specific Gravity Bottle (Pyknometer)
Material	Borosilicate 3.3 glass
Stopper	Ground-glass interchangeable stopper with fine capillary vent
Capacity	Supplied in a range of standard laboratory capacities — confirm exact volume at enquiry
Typical Use	Determination of liquid density and relative density (specific gravity) against water
Common Settings	Chemistry laboratories, pharmaceutical QC, petrochemical and beverage testing

Applications

Determining relative density (specific gravity) of liquids in chemistry teaching and research laboratories
Pharmaceutical quality-control testing of syrups, solvents, and formulations
Density checks on oils, fuels, and petrochemical samples
Beverage and food-testing laboratories checking syrup or liquid concentration
Calibration verification exercises in analytical chemistry courses

Care & Handling

Always keep the ground-glass stopper matched to its own bottle; do not swap stoppers between units as the ground fit is unique to each pair.
Clean thoroughly with a suitable laboratory detergent and rinse with distilled water before and after each determination to avoid contaminating results.
Dry the bottle and stopper carefully, ensuring the capillary bore is clear, before storage.
Handle the ground-glass joint gently — avoid dropping or knocking the stopper against the neck, which can chip the precision-ground surface.
Store upright in a dry cabinet, away from other glassware that could chip the stopper or neck on contact.

Why Choose LabEquip

LabEquip supplies borosilicate laboratory glassware, including relative density bottles, alongside a broader range of lab glassware and general chemistry lab equipment for schools, colleges, and industrial laboratories. Each item is checked before dispatch, and our team can help you confirm the right capacity and specification for your testing method. For bulk orders, institutional procurement, or technical questions about this product, please contact us and our team will assist promptly.

Frequently Asked Questions

What is a relative density bottle used for?

A relative density bottle, or pyknometer, is used to measure the density of a liquid and its relative density (specific gravity) compared with water, by weighing a precisely fixed volume of the sample.

How does the ground-glass stopper ensure accurate results?

The stopper has a fine capillary bore that lets excess liquid escape as it is inserted, so the bottle always holds the same internal volume of liquid, making repeated weighings comparable and accurate.

Can stoppers be interchanged between different relative density bottles?

No. Each stopper is individually ground to fit its own bottle precisely, so stoppers should never be swapped between different units, as this can affect the sealed volume and the accuracy of results.

What material is the relative density bottle made from?

It is made from borosilicate 3.3 glass, chosen for its chemical resistance, dimensional stability, and resistance to thermal shock, which help keep density measurements consistent over repeated use.

What capacity does the relative density bottle come in?

These bottles are supplied in a range of standard laboratory capacities. Please confirm the exact volume you require for your test method when you enquire, and our team will help you select the right size.

How should a relative density bottle be cleaned and stored?

Clean it with a suitable laboratory detergent, rinse with distilled water, and dry carefully including the capillary bore. Store the bottle and its matched stopper together, upright, in a dry cabinet away from other glassware.

Last Updated: September 2026

Reagent Bottle, Wide Mouth (Clear Glass)

Quick Answer: A clear glass wide mouth reagent bottle is a transparent glass storage bottle with a broad neck, used for solid chemicals and small specimens that need to be seen as well as reached. The clear body shows the colour and condition of the contents, and the wide opening admits a spatula or scoop.

Seeing the Solid Before You Open It

Solid reagents change in storage just as liquids do. Copper(II) sulfate crystals can lose their blue colour at the surface as they give up water, sodium hydroxide pellets go wet and slumped as they absorb moisture, and iron(II) salts turn from green towards brown on oxidation. A clear glass wide mouth reagent bottle makes these changes visible without opening it, so a technician can tell at a glance whether a solid is still fit for a practical.

Glass has a second advantage over plastic for solids: it does not absorb odours or stains, and it is inert towards most organic compounds. That suits substances such as naphthalene, benzoic acid or iodine crystals, which could interact with plastic or pass slowly into it.

Where a plastic or unspecified-material version is wanted, LabEquip lists the Reagent Bottle, Wide Mouth separately. For liquid reagents, narrow-neck bottles pour more cleanly and evaporate less.

Applications

Display sets of common salts and elements for identification lessons
Organic solids such as benzoic acid or naphthalene used in melting point and recrystallisation practicals
Storing iodine crystals and other solids that would stain or penetrate plastic containers
Keeping dry specimens where students need to see them without opening the bottle

Care & Handling

Tap loose solid back down from the neck before closing so crystals are not trapped in the closure.
Keep hygroscopic solids tightly closed and, where a bottle is opened often, decant a smaller working portion for daily use.
Carry glass bottles by the body with a hand under the base, not by the neck or lid.
Store the bottle in a closed cupboard if the solid is light-sensitive, since clear glass gives no protection from light.

Specifications

Item	Wide-neck reagent bottle for solids and specimens
Material	Clear glass, as named in the title; glass type not stated
Opening	Broad mouth for spatula, scoop or specimen access
Suits	Crystals, powders, granules and organic solids
Capacity and closure type	Confirm at enquiry

Why Choose LabEquip

Science departments use clear wide-mouth bottles for reagent displays and for the organic solids handled in college practicals. LabEquip supplies them within its chemistry equipment section; share sizes and the number of bottles needed via the LabEquip contact page.

Frequently Asked Questions

What is the difference between this bottle and the plain wide mouth reagent bottle?

This listing specifies clear glass. The plain wide mouth listing does not name a material and may be supplied in other materials such as plastic, so choose this one when you want transparent, glass-bodied storage for solids.

Why store iodine crystals in glass rather than plastic?

Iodine slowly sublimes, and its vapour stains and passes into many plastics. A glass bottle with a well-fitting closure contains it better. Keep the bottle in a cool, closed cupboard.

Can solids that react with glass be stored in it?

Most solid salts are fine in glass. Fluoride salts in damp conditions, and strong alkalis over long periods, can slowly attack glass, so those are often kept in plastic containers instead.

How do I dry out a solid that has absorbed moisture?

Many salts can be dried on a watch glass in a warm oven or a desiccator, but some decompose on heating, and deliquescent solids such as sodium hydroxide cannot be restored this way. Look up the substance before heating it.

Is a wide mouth bottle suitable for liquids?

It can hold liquids, but pouring from a wide neck is harder to control and liquids evaporate faster through the larger opening. A narrow mouth bottle is the usual choice for liquid reagents.

How should the bottle be labelled for a display set?

Label with the chemical name, formula and any hazard pictograms on the side facing the viewer, and record when each sample was added. Replace samples whose colour or appearance changes.

Last Updated: September 2026

Reagent Bottle, Wide Mouth

Quick Answer: A wide mouth reagent bottle is a laboratory storage bottle with a broad neck, used for solids such as powders, crystals, granules and pellets that are taken out with a spatula or scoop. The wide opening also makes the bottle easy to fill and to clean.

Specifications

Item	Reagent bottle with a wide neck for solids
Access	Spatula or scoop reaches the contents directly
Typical contents	Powders, crystals, granules, pellets, small specimens
Related listing	Clear-glass wide mouth version listed separately
Material and capacity	Confirm at enquiry

Built Around the Spatula

Solid reagents cannot be poured accurately through a narrow neck, and tapping a bottle to shake out crystals wastes material and spreads dust. A wide mouth reagent bottle lets a spatula or scoop reach inside, so marble chips, copper(II) sulfate crystals, zinc granules or sodium chloride can be taken out in measured amounts while the rest stays undisturbed.

The title does not state the material. LabEquip lists a clear-glass version separately as the Reagent Bottle, Wide Mouth (Clear Glass), and this listing may cover other materials such as polypropylene, so confirm the material when ordering. Polypropylene is light, does not shatter when dropped and resists most aqueous acids and alkalis, which makes it a common choice for solids handled by students.

The drawback of a broad opening is exposure to air each time the bottle is opened. Hygroscopic solids such as sodium hydroxide pellets and anhydrous calcium chloride take up moisture quickly, so they should be scooped out promptly and the bottle closed straight away.

Applications

Storing granular and crystalline salts for preparation and analysis practicals
Keeping metal granules, turnings or marble chips for rates-of-reaction experiments
Holding sodium hydroxide pellets or drying agents under a well-closed lid
Carrying soil or rock samples back from fieldwork, when a plastic version is supplied

Care & Handling

Use a clean, dry spatula for each reagent; a damp spatula starts caking inside the bottle.
Wipe powder from the rim and neck before closing so the closure seats properly.
If a plastic version is supplied, keep it away from heat sources and check compatibility before storing organic solvents or strong oxidisers in it.
Break up caked solids gently with a glass rod rather than by knocking the bottle on the bench.

Why Choose LabEquip

Laboratory stores managers and chemistry teachers order wide-mouth bottles to decant bulk solids into smaller, labelled bench quantities. LabEquip carries them in the chemistry lab equipment range with bottles for liquids such as the Reagent Bottle, Narrow Mouth; send the material and sizes you need through the contact page.

Frequently Asked Questions

Why are solids kept in wide mouth bottles?

Solids have to be removed with a spatula or scoop, and a wide neck gives room to do that without spilling or tipping the bottle. It also makes it easier to see how much is left and to clean out residues.

Is plastic or glass better for a wide mouth reagent bottle?

Plastic such as polypropylene is lighter, will not shatter and suits most salts, acids and alkalis. Glass is preferred for organic solids and for substances such as iodine that can stain or pass into plastic.

How do I stop sodium hydroxide pellets from turning wet?

Sodium hydroxide absorbs water and carbon dioxide from air, so the pellets become damp and stick together. Open the bottle only briefly, close it firmly, and avoid storing it in a humid room. Glass stoppers should not be used on alkali containers.

Can I use the bottle for biological specimens?

A wide mouth bottle is convenient for small preserved specimens or field samples because they can be put in and taken out easily. Make sure the bottle material and closure are compatible with the preservative being used.

How should solid reagents be dispensed in class?

Weigh or measure portions from the stock bottle into labelled weighing boats or smaller containers for students, rather than passing the stock bottle around. This keeps the main supply clean and dry.

Why does the lid stick after a few weeks?

Fine powder caught in the neck, or crystals formed from a damp solid, bind the closure. Wiping the neck before closing prevents most sticking, and a stuck lid can usually be freed by standing the neck in warm water for a short time.

Last Updated: September 2026