Laboratory Equipment

In a laboratory a condenser is a piece of laboratory glassware used to cool hot vapors or liquids. A condenser usually consists of a large glass tube containing a smaller glass tube running its entire length, within which the hot fluids pass.

The ends of the inner glass tube are usually fitted with ground glass joints which are easily fitted with other glassware. The upper end is usually left open to the atmosphere, or vented through a bubbler, or a drying tube to prevent the ingress of water or oxygen.

The outer glass tube usually has two hose connections, and a coolant (usually tap water or chilled water/anti-freeze mixture) is passed through it. For maximum efficiency, the cold water always enters through the bottom fitting, and exits through the top fitting. Multiple condensers may be connected in series. Normally a high flow rate is not necessary to maintain a cooling surface.

Condensers are often used in reflux, where the hot solvent vapors of a liquid being heated are cooled and allowed to drip back. This reduces the loss of solvent allowing the mixture to be heated for extended periods.

Condensers are used in distillation to cool the hot vapors, condensing them into liquid for separate collection. For fractional distillation, an air or Vigreux condenser is usually used to slow the rate at which the hot vapors rise, giving a better separation between the different components in the distillate.

For microscale distillation, there are commercially available apparatus which include the "pot", and the condenser fused into one-piece. This reduces the hold-up volume, and obviates the need for ground glass joints preventing contamination by grease and air leaks.

For other uses, see Spatula (disambiguation).
A common spatula design

A turner (in British English), or fish slice, is a kitchen utensil with a long handle and a broad flat edge, used for lifting fried foods.[1][2] Though the word spatula is used in British English, it refers solely to a mixing and spreading implement.[3] Often the plate scraper is referred to as a spatula. In some parts of Scotland (e.g. Glasgow or Victoria Halls[citation needed]) the spatula is also known as a tosser which refers to the tossing of omelettes or pancakes.

The word spatula, known in English since 1525, is a diminutive form of the Latin term spatha, which means a broad sword (as in spatharius) or a flat piece of wood and is also the origin of the words spade (digging tool) and spathe.[4]

Spatulas have a handle that is long enough to keep the holder's hand away from what is being lifted, flipped, or scraped. The blade is usually somewhat flexible, and shiny. Spatula blades are often longer on the right side than the left, as this is more effective for right-handed people. There are also left-handed spatulas, but these are rare. Most have long slots on the blades to allow liquids to flow through, though some have holes or no perforations at all.

Spatulas are usually made of plastic or metal, with a wooden or plastic handle to insulate them from heat. Spatulas made for outdoor grilling have very long handles.

Spatulas can be colorful or have artistic designs. They can be used as decorations in the home or used in some abstract art forms.

Sartorius Stedim Biotech’s new high-speed benchtop centrifuge Centrisart A -14 is ideally suited for use of VoluPAC biomass determination tubes, Vivaspin 500 ultrafiltration devices and all other standard microtubes. The large display allows high legibility of the values for speed, relative centrifugal force and running time. All parameters are set quickly and simply with push buttons. The Centrisart A -14 is equipped with a 12-place polypropylene rotor and operates smoothly and quietly.

A burette (also buret) is a vertical cylindrical piece of laboratory glassware with a volumetric graduation on its full length and a precision tap, or stopcock, on the bottom. It is used to dispense known amounts of a liquid reagent in experiments for which such precision is necessary, such as a titration experiment. Burettes are extremely accurate: class A burettes are accurate to ± 0.05 cm3.

The precision of a burette makes careful measurement with a burette very important to avoid systematic error. When reading a burette, the viewer's eyes must be at the level of the graduation to avoid parallax error. Even the thickness of the lines printed on the burette matters; the bottom of the meniscus of the liquid should be touching the top of the line you wish to measure from. A common rule of thumb is to add 0.02 mL if the bottom of the meniscus is touching the bottom of the line[citation needed]. Due to the precision of the burette, even a single drop of liquid hanging from the bottom of a burette should be transferred to the receiving flask, usually by touching the drop to the side of the receiving flask. Through careful control of the stopcock and rinsing, even partial drops of liquid can be added to the receiving flask.

A Glass Beaker is a simple container for stirring, mixing and heating liquids commonly used in many laboratories. Beakers are generally cylindrical in shape, with a flat bottom. Beakers are available in a wide range of sizes, from one millilitre up to several litres.

They may be made of glass (very often borosilicate glass) or of various plastics. Beakers used for holding solutions of corrosive chemicals such as acids or other highly reactive chemicals, are often made of PTFE or other low reactivity materials. Beakers have a cylindrical shape, with flat bottoms so that that they can be set onto many different types of surfaces, and they usually have a thick top (lip) with a spout to make it easier to pour liquids.

Beakers may be covered, perhaps by a watch glass, to prevent contamination or loss of the contents. Beakers are often graduated—marked on the side with lines indicating the volume contained. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL of volume. The accuracy of these marks can vary from one beaker to another. The standard tall form graduated beaker is sometimes referred to as a Berzelius beaker.

A beaker is distinguished from a flask by having sides which are straight rather than sloping. The exception to this definition is a slightly conical sided beaker is called a Phillips beaker.

An Erlenmeyer flask, commonly known as a conical flask or E-flask, is a widely used type of laboratory flask which features a conical base and a cylindrical neck. They are usually marked on the side (graduated) to indicate the approximate volume of their contents. It is named after the German chemist Emil Erlenmeyer, who created it in 1861.

The conical flask is similar to the beaker, but is distinguished by its narrow neck. The neck allows the flask to be stoppered using rubber bungs or cotton wool. The conical shape allows the contents to be swirled or stirred during an experiment (as is required in titration); the narrow neck keeps the contents from spilling. The smaller neck also slows evaporative loss better than a beaker. The flat bottom of the conical flask makes it unlikely to tip over, unlike the Florence flask.

Erlenmeyer flasks are used for pH titrations and in microbiology for the preparation of microbial cultures. Plastic Erlenmeyer flasks used in cell culture are pre-sterilized and feature closures and vented closures to enhance gas exchange during incubation and shaking.

If the flask is to be heated in an oil or water bath, a 'C' shaped lead or iron weight may be placed over the outside to keep the flask firmly planted.

When heating, it is usually placed on a ring held to a ring stand by means of a ring clamp. The ring keeps it over a Bunsen burner so that it is heated by the flame of the burner. When set up this way, a wire gauze mesh or pad is placed between the ring and the flask to prevent the flames from directly touching the glass. An alternative way to set up the apparatus is to clamp the flask directly to the ring stand by means of holding it with a test tube clamp around the neck of the flask.

This article is about the laboratory instrument. For the band, see The Pipettes.
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A selection of pipettes

A pipette (also called a pipet, pipettor or chemical dropper) is a laboratory instrument used to transport a measured volume of liquid.

Pipettes are commonly used in chemistry and molecular biology research as well as medical tests. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. A pipette works by creating a vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid.

Pipettes that dispense between 1 and 1000 μl are termed micropipettes, while macropipettes dispense a greater volume of liquid.

Volumetric pipettes allow the user to measure a volume of solution extremely accurately and then add it to something else. They are commonly used to make laboratory solutions from a base stock as well as prepare solutions for titration. They are typically marked to indicate one single volume in a particular size pipette (as are volumetric flasks). Many different sizes are available.

Graduated pipettes, also called Mohr pipettes, use a series of marked lines (as on a graduated cylinder) to indicate different calibrated volumes. These also come in a variety of sizes. These are used much like a burette, in that the volume is found by calculating the difference of the liquid level before and after liquid is dispensed. Typically the precision of a graduated pipette is not as great as that of a volumetric pipette.[citation needed]

A Pasteur pipette is not calibrated for any particular volume. Rather, it is essentially a large dropper, which can be used to remove liquid from one container and add it to another.

Variable volume air displacement pipettes are micropipettes which dispense an adjustable volume of liquid from a disposable tip. The pipette body contains a plunger, which provides the suction to pull liquid into the tip when the piston is compressed and released. The maximum displacement of the plunger is set by a dial on the pipette body, allowing the delivery volume to be changed.

A Beral pipette is a one-piece pipette, usually made from flexible soft plastic (polyethylene) that has a built-in bulb on the end.

All glass pipettes require the use of some kind of additional suction device, typically a pipette bulb, which is a rubber bulb which sucks the liquid into the pipette and also allows you to drain the pipette in a controlled fashion. Before this, it was common practice to "mouth pipette" i.e. to aspirate fluid into the pipette by applying suction with one's mouth.

The original pipette is made of glass. It is more commonly used in chemistry, with aqueous solutions. There are two types. One type, the volumetric pipette, has a large bulb, and is calibrated for a single volume. Typical volumes are 10, 25, and 50 mL. Alternatively, Mohr pipettes are straight-walled, and graduated for different volumes such as 5 mL in 0.5 mL increments. The single volume pipette is usually more accurate, with an error of ± 0.1 or 0.2 mL.

The pipette is filled by dipping the tip in the volume to be measured, and drawing up the liquid with a pipette filler past the inscribed mark. The volume is then set by releasing the vacuum using the pipette filler or a damp finger. While moving the pipette to the receiving vessel, care must be taken not to shake the pipette because the column of fluid may "bounce".