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44-401: The first simple pipettes were made of glass, such as Pasteur pipettes . Large pipettes continue to be made of glass; others are made of squeezable plastic for situations where an exact volume is not required. The first micropipette was patented in 1957 by Dr Heinrich Schnitger ( Marburg , Germany). The founder of the company Eppendorf , Dr. Heinrich Netheler, inherited the rights and started

88-406: A liquid. A burette is a volumetric measuring glassware which is used in analytical chemistry for the accurate dispensing of a liquid, especially of one of the reagents in a titration. The burette tube carries graduated marks from which the dispensed volume of the liquid can be determined. Compared to a volumetric pipette , a burette has similar precision if used to its full capacity, but as it

132-527: A low arm and elbow height and relaxing the shoulders and upper arms. Typically the pipettes are vertically stored on holder called pipette stands. In case of electronic pipettes, such stands can recharge their batteries. The most advanced pipette stands can directly control electronic pipettes. An alternative technology, especially for transferring small volumes (micro and nano litre range) is acoustic droplet ejection . Pasteur pipette An eye dropper , also called Pasteur pipette or simply dropper ,

176-411: A motorized pipette controller can aid liquid aspiration or dispensing using volumetric pipettes or graduated pipettes; a tablet can interact in real-time with the pipette and guide a user through a protocol; and a pipette station can help to control the pipette tip immersion depth and improve ergonomics. Pipette robots are capable of manipulating pipettes just as humans would do. Pipette recalibration

220-469: A positive displacement operation. Such a device can be used on a wide variety of fluids (aqueous, viscous, and volatile fluids; hydrocarbons; essential oils; and mixtures) in volumes between 0.5 mL and 25 mL. This arrangement provides improvements in precision, handling safety, reliability, economy, and versatility. No disposable tips or pipetting aids are needed with the pipetting syringe. The Van Slyke pipette, invented by Donald Dexter Van Slyke ,

264-477: A rubber bulb at the open end of the pipette preventing any contamination from the atmosphere. Generally, they are considered cheap enough to be disposable, however, so long as the glass point is not chipped, the eye dropper may be washed and reused indefinitely. In laboratory use, droppers should not be used for work involving high accuracy since droppers are not designed to measure specific volume; however, it can be used to add drops of reagents. Each type of dropper

308-402: A single piece of plastic and their bulb can serve as the liquid-holding chamber. Pipetting syringes are hand-held devices that combine the functions of volumetric (bulb) pipettes, graduated pipettes, and burettes . They are calibrated to ISO volumetric A grade standards. A glass or plastic pipette tube is used with a thumb-operated piston and PTFE seal which slides within the pipette in

352-441: A specialized grease. Burettes are manufactured for specific tolerances, designated as class A or B and this also is etched on the glass. In order to measure the amount of solution added in or drained out, the burette must be observed at eye level straight to the bottom of the meniscus . The liquid in the burette should be completely free of bubbles to ensure accurate measurements. The difference in volume can be calculated by taking

396-406: A type of adjustable micropipette that deliver a measured volume of liquid; depending on size, it could be between about 0.1  μL to 1,000 μL (1 mL). These pipettes require disposable tips that come in contact with the fluid. These pipettes operate by piston -driven air displacement. A vacuum is generated by the vertical travel of a metal or ceramic piston within an airtight sleeve. As

440-444: A type of macropipette consisting of a long tube with a series of graduations, as on a graduated cylinder or burette , to indicate different calibrated volumes. They also require a source of vacuum; in the early days of chemistry and biology, the mouth was used. The safety regulations included the statement: "Never pipette by mouth KCN, NH3, strong acids, bases and mercury salts". Some pipettes were manufactured with two bubbles between

484-419: Is a device used to transfer small quantities of liquids. They are used in the laboratory and also to dispense small amounts of liquid medicines. A very common use was to dispense eye drops into the eye. The commonly recognized form is a glass tube tapered to a narrow point (a pipette ) and fitted with a rubber bulb at the top, although many styles of both plastic and glass droppers exist. The combination of

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528-403: Is a graduated pipette commonly used in medical technology with serologic pipettes for volumetric analysis. The Ostwald–Folin pipette, developed by Wilhelm Ostwald and refined by Otto Folin , is a type of volumetric pipette used to measure viscous fluids such as whole blood or serum. The Winkler–Dennis gas combustion pipette, developed by Clemens Winkler and refined by Louis Munroe Dennis,

572-549: Is also more economical since the glass can be fabricated easily compared to other types. Soda lime glass, although not as chemically resistant as borosilicate glass, are suitable as a material for inexpensive apparatus such as the Pasteur pipette. Glass pasteur pipettes can be used to make spotters for thin layer chromatography after pulling it over a flame, though it may take some practice. Plastic Pasteur pipettes, also referred to as transfer pipettes , have their stems and bulbs in

616-608: Is an apparatus for the controlled reaction of liquids under a mild electric current and a supply of oxygen. Glass micropipettes are fabricated in a micropipette puller and are typically used in a micromanipulator . These are used to physically interact with microscopic samples, such as in the procedures of microinjection and patch clamping . Most micropipettes are made of borosilicate , aluminosilicate or quartz with many types and sizes of glass tubing being available. Each of these compositions has unique properties which will determine suitable applications. A recent introduction into

660-574: Is an important consideration in laboratories using these devices. It is the act of determining the accuracy of a measuring device by comparison with NIST traceable reference standards. Pipette calibration is essential to ensure that the instrument is working according to expectations and as per the defined regimes or work protocols. Pipette calibration is considered to be a complex affair because it includes many elements of calibration procedure and several calibration protocol options as well as makes and models of pipettes to consider. Proper pipetting posture

704-432: Is designed to produce a specific drop volume, but this is not highly precise. Before using a dropper, the tip should be carefully examined for cracks. To increase accuracy, the pipette is to be rinsed with the reagent. To use the dropper, the bulb is squeezed to expel air out of the pipette and the tip of the pipette is submerged into the solution vertically. The bulb is slowly released to draw the solution up, making sure that

748-403: Is held in a fixed position and the plunger is moved incrementally either by turning wheel by hand, or by means of a step motor. The volume is shown on a digital display. A high-precision syringe may be used to deliver very precise aliquots. Motorized digital burettes may be controlled by a computer; for example, a titration may be recorded digitally and then subject to numerical processing to find

792-445: Is not important. (Most organic solvents , such as hexane and acetone cannot be used in plastic Pasteur pipettes as the solvent can dissolve the plastic.) The pipettes are also hard to wash and are usually discarded with other biohazard waste after one use. Plastic bulb pipettes are generally not precise enough to be used for exact measurements, whereas their glass counterparts can be extremely precise. The constriction toward

836-412: Is placed into a small reaction tube along with a boiling chip and heated to reflux one-half to two-thirds of the way up the inside of the tube. After squeezing the bulb to expel air, a pasteur pipette is inserted into the tube just below the level of the ring of refluxing liquid (into the vapor). The vapor is then drawn into the relatively cold pipette tip, causing it to condense and accumulate inside of

880-492: Is preferred to Class B when volumetric accuracy is important, as it has a narrower range of error with accuracy up to 0.1 percent compared to 0.2 percent in Class B burette. Digital burettes are based on a syringe design. The barrel and plunger may be made of glass. With liquids that corrode glass, including solutions of alkali , the barrel and plunger may be made of polyethylene or another resistant plastic material. The barrel

924-427: Is relatively inexpensive and disposable, so they are often used to avoid cross-contamination. In a solution containing cells and/or protein, it reduces the loss of cell and/or protein that binds to glass. Some plastic pipettes include a long flexible tube that can be bent for drawing solution from small volume tubes. Plastic Pasteur pipettes are often used in biology where most media are aqueous and solvent resistance

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968-874: Is the most important element in establishing good ergonomic work practices. During repetitive tasks such as pipetting, maintaining body positions that provide a maximum of strength with the least amount of muscular stress is important to minimize the risk of injury. A number of common pipetting techniques have been identified as potentially hazardous due to biomechanical stress factors. Recommendations for corrective pipetting actions, made by various US governmental agencies and ergonomics experts, are presented below. Unlike traditional axial pipettes, ergonomic pipetting can affect posture and prevent common pipetting injuries such as carpal tunnel syndrome, tendinitis and other musculoskeletal disorders. To be "ergonomically correct" significant changes to traditional pipetting postures are essential, like: minimizing forearm and wrist rotations, keeping

1012-401: Is usually used to deliver less than its full capacity, a burette is slightly less precise than a pipette. The burette is used to measure the volume of a dispensed substance, but is different from a graduated cylinder as its graduations measure from top to bottom. Therefore, the difference between the starting and the final volume is equal to the amount dispensed. The precision and control of

1056-431: The 19th century. He is widely recognized for developing the pasteurization process , and the pipettes were named in his honor. The two types of glass that are usually found in the laboratory and in the Pasteur pipette are borosilicate glass and soda–lime glass . Borosilicate glass is a widely used glass for laboratory apparatus, as it can withstand chemicals and temperatures used in most laboratories. Borosilicate glass

1100-465: The burette over other means of adding solution is beneficial for use in titration . A volumetric burette can be made of glass or plastic, and is a straight tube with a  graduation  scale. At the tip of burette, there are a  stopcock and valve to control the flow of the chemical solution. The barrel of the stopcock can be made of  glass  or the plastic  PTFE . Stopcocks with glass barrels need to be lubricated with vaseline or

1144-476: The changing environment, particularly temperature and user technique. For these reasons, this equipment must be carefully maintained and calibrated, and users must be trained to exercise correct and consistent technique. The micropipette was invented and patented in 1960 by Dr. Heinrich Schnitger in Marburg , Germany. Afterwards, the co-founder of the biotechnology company Eppendorf , Dr. Heinrich Netheler, inherited

1188-689: The commercial production of micropipettes in 1961. The adjustable micropipette is a Wisconsin invention developed through interactions among several people, primarily inventor Warren Gilson and Henry Lardy, a professor of biochemistry at the University of Wisconsin–Madison . Although specific names exist for each type of pipette, in practice, any type can be referred to as a "pipette". Pipettes that dispense less than 1000  μL are sometimes distinguished as micropipettes. The terms "pipette" and "pipet" are used interchangeably despite minor historical differences in their usage. Air displacement micropipettes are

1232-434: The difference of the final and initial recorded volume. Using the burette with a colorless solution may make it difficult to observe the bottom of the meniscus, so the black strip technique can make it easier to accurately observe and record measurements. The specification of a volumetric burette indicates its properties, such as the nominal volume, volume unit, error limit, and accuracy class, plus other related details from

1276-437: The drug or food industries are required to calibrate their pipettes quarterly (every three months). Schools which are conducting chemistry classes can have this process annually. Those studying forensics and research where a great deal of testing is commonplace will perform monthly calibrations. To minimize the possible development of musculoskeletal disorders due to repetitive pipetting, electronic pipettes commonly replace

1320-429: The form of a single piece made of soft plastic such as polyethylene . The bulb portion is thinner and therefore "squeezable", while the pipette portion is thick enough to be rigid. They commonly come in 1, 2, 3, and 5 ml which comes with a specific drop size of 10, 20, 25, 35, and 50 μL. The volumes are usually marked on the stem, though the markings are rather crude and are not particularly accurate. A plastic dropper

1364-442: The manufacturer. The nominal volume and error limit is usually given in units of mL or cm . Another specification commonly found on burettes is the calibration mark "TD" or "Ex". This stands for "calibrated to deliver", indicating that the printed volume is accurate when the burette is used to deliver (rather than contain) a solution. Another commonly indicated specification is the accuracy class, including class A and class B. Class A

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1408-432: The mechanical version. These are similar to air displacement pipettes, but are less commonly used and are used to avoid contamination and for volatile or viscous substances at small volumes, such as DNA . The major difference is that the disposable tip is a microsyringe (plastic), composed of a capillary and a piston (movable inner part) which directly displaces the liquid. Volumetric pipettes or bulb pipette allow

1452-444: The medical lab. It produces a constant volume of drop. This reduces the concern of liquid remaining in the pipette. Burette A burette (also spelled as buret ) is a graduated glass tube with a tap at one end, for delivering known volumes of a liquid, especially in titrations . It is a long, graduated glass tube, with a stopcock at its lower end and a tapered capillary tube at the stopcock's outlet. The flow of liquid from

1496-549: The micropipette field integrates the versatility of microfluidics into a freely positionable pipette platform. At the tip of the device, a localized flow zone is created which allows for constant control of the nanolitre environment, directly in front of the pipette. The pipettes are made from polydimethylsiloxane (PDMS), which is formed using reactive injection molding. Interfacing of these pipettes using pneumatics enables multiple solutions to be loaded and switched on demand, with solution exchange times of 100ms. This type of pipette

1540-527: The mouth piece and the solution level line, to protect the chemist from accidental swallowing of the solution. Pasteur pipettes are plastic or glass pipettes used to transfer small amounts of liquids, but are not graduated or calibrated for any particular volume. The bulb is separate from the pipette body. Pasteur pipettes are also called teat pipettes , droppers , eye droppers and chemical droppers . Transfer pipettes , also known as Beral pipettes , are similar to Pasteur pipettes but are made from

1584-555: The pipette and rubber bulb has also been referred to as a teat pipette. The Pasteur pipette name is from the French scientist Louis Pasteur , who used a variant of them extensively during his research. In the past, there was no equipment to transfer a chemical solution without exposing it to the external environment. The hygiene and purity of chemical compounds is necessary for the expected result of each experiment. The eye dropper, both glass and plastic types, can be sterilized and plugged with

1628-402: The pipette. Heat can be applied to the tip of a plastic Pasteur pipette to seal the solution and create a liquid-tight storage. Medical laboratories required high efficiency and precision for drug test and observation of diseases. Pasteur pipettes are commonly used in the medical lab because of its essential accuracy. The design of the Pasteur pipette allows for high effective performance in

1672-413: The piston moves upward, driven by the depression of the plunger, a vacuum is created in the space left vacant by the piston. The liquid around the tip moves into this vacuum (along with the air in the tip) and can then be transported and released as necessary. These pipettes are capable of being very precise and accurate. However, since they rely on air displacement, they are subject to inaccuracies caused by

1716-499: The rights and initiated the global and general use of micropipettes in labs. In 1972, the adjustable micropipette was invented at the University of Wisconsin-Madison by several people, primarily Warren Gilson and Henry Lardy. Types of air displacement pipettes include: Irrespective of brand or expense of pipette, every micropipette manufacturer recommends checking the calibration at least every six months, if used regularly. Companies in

1760-407: The solution does not overshoot into the bulb or else it may get contaminated. To dispense the reagent, the tip is held against the side of the target container at a 30 to 45 degrees angle. Broken pasteur pipettes should be disposed of in an appropriate glassware container . This liquid handling tool, known as the "Pasteur Pipette," was first discovered by the renowned scientist Louis Pasteur in

1804-528: The tip of the Pasteur pipettes may be plugged with a bit of tissue paper or cotton wool to filter off solids from small amounts of liquids. The bulb can be attached and squeezed to help viscous solutions filter more rapidly. With a bit of skill, Pasteur pipettes may also be used for microscale column chromatography . With appropriately fine silica gel , the bulb may be squeezed for microscale flash column chromatography . Pasteur pipettes can also be used for microscale distillation . The liquid to be distilled

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1848-406: The tube to the burette tip is controlled by the stopcock valve. There are two main types of burette; the volumetric burette and the piston burette. A volumetric burette delivers measured volumes of liquid. Piston burettes are similar to syringes , but with a precision bore and a plunger. Piston burettes may be manually operated or may be motorized. A weight burette delivers measured weights of

1892-465: The user to measure a volume of solution extremely precisely (precision of four significant figures). These pipettes have a large bulb with a long narrow portion above with a single graduation mark as it is calibrated for a single volume (like a volumetric flask ). Typical volumes are 20, 50, and 100 mL. Volumetric pipettes are commonly used to make laboratory solutions from a base stock as well as prepare solutions for titration . Graduated pipettes are

1936-594: Was invented by Alar Ainla, and currently situated in the Biophysical Technology Lab. at Chalmers University of Technology in Sweden. A zeptolitre pipette has been developed at Brookhaven National Laboratory . The pipette is made of a carbon shell, within which is an alloy of gold-germanium. The pipette was used to learn about how crystallization takes place. A variety of devices have been developed for safer, easier, and more efficient pipetting. For example,

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