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Pipettors
A pipette (sometimes spelled as pipett) is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. 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. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the instrument. History The first simple pipettes were made in glass, such as Pasteur pipettes. Large pipettes continue to be made in glass; others are made in 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 the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Media Dispenser
A media dispenser or a culture media dispenser is a device for repeatedly delivering small fixed volumes (typically between 1 ml and 50 ml) of liquid such as a laboratory growth medium like molten agar or caustic or volatile solvents like toluene into a series of receptacles (Petri dishes, test tubes, Fernbach flasks, etc.). It is often important that such dispensers operate without biological or chemical contamination, and so must be internally sealed from the environment and designed for easy cleaning and sterilization before use. At a minimum, a media dispenser consists of some kind of pump connected to a length of discharge tubing or a spout. Dispensers used in laboratories are also frequently connected to microcontrollers to regulate the speed and volume of the medium as it leaves the pump. Laboratory media dispensers may include the following, among others: floating piston designs, syringe pumps, peristaltic pumps, pipettes or pipettors, and pressure injection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipettes
A pipette (sometimes spelled as pipett) is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. 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. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the instrument. History The first simple pipettes were made in glass, such as Pasteur pipettes. Large pipettes continue to be made in glass; others are made in 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 the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microlitre
The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3). A cubic decimetre (or litre) occupies a volume of (see figure) and is thus equal to one-thousandth of a cubic metre. The original French metric system used the litre as a base unit. The word ''litre'' is derived from an older French unit, the '' litron'', whose name came from Byzantine Greek—where it was a unit of weight, not volume—via Late Medieval Latin, and which equalled approximately 0.831 litres. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI,Bureau International des Poids et Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graduated Cylinder
A graduated cylinder, also known as a measuring cylinder or mixing cylinder, is a common piece of laboratory equipment used to measure the volume of a liquid. It has a narrow cylindrical shape. Each marked line on the graduated cylinder represents the amount of liquid that has been measured. Materials and structure Large graduated cylinders are usually made of polypropylene for its excellent chemical resistance or polymethylpentene for its transparency, making them lighter and less fragile than glass. Polypropylene (PP) is easy to repeatedly autoclave; however, autoclaving in excess of about (depending on the chemical formulation: typical commercial grade polypropylene melts in excess of ), can warp or damage polypropylene graduated cylinders, affecting accuracy. A traditional graduated cylinder is usually narrow and tall so as to increase the accuracy and precision of volume measurement. It has a plastic or glass base (stand, foot, support) and a "spout" for easy pouring of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graduated Pipettes
A graduated pipette is a pipette with its volume, in increments, marked along the tube. It is used to accurately measure and transfer a volume of liquid from one container to another. It is made from plastic or glass tubes and has a tapered tip. Along the body of the tube are graduation markings indicating volume from the tip to that point. A small pipette allows for more precise measurement of fluids; a larger pipette can be used to measure volumes when the accuracy of the measurement is less critical. Accordingly, pipettes vary in volume, with most measuring between . Types Mohr and Serological pipettes There are two types of pipettes that differ based on where the markings are located in reference to the pipette tip. These are Mohr pipettes and Serological pipettes, and they differ only by the position of the first graduation mark, nearest the tip of the pipette. A Mohr pipette is designed for use as a drain-out pipette. It has a straight tube and graduation marks indica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titration
Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the ''titrant'' or ''titrator'', is prepared as a standard solution of known concentration and volume. The titrant reacts with a solution of ''analyte'' (which may also be termed the ''titrand'') to determine the analyte's concentration. The volume of titrant that reacted with the analyte is termed the ''titration volume''. History and etymology The word "titration" descends from the French word ''titrer'' (1543), meaning the proportion of gold or silver in coins or in works of gold or silver; i.e., a measure of fineness or purity. ''Tiltre'' became ''titre'', which thus came to mean the "fineness of alloyed gold", and then the "concentration of a substance in a given sample". In 1828, the French chemist Joseph Louis Gay-Lussac first used ''titre'' as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volumetric Flask
A volumetric flask (measuring flask or graduated flask) is a piece of laboratory apparatus, a type of laboratory flask, calibrated to contain a precise volume at a certain temperature. Volumetric flasks are used for precise dilutions and preparation of standard solutions. These flasks are usually pear-shaped, with a flat bottom, and made of glass or plastic. The flask's mouth is either furnished with a plastic snap/screw cap or fitted with a joint to accommodate a PTFE or glass stopper. The neck of volumetric flasks is elongated and narrow with an etched ring graduation marking. The marking indicates the volume of liquid contained when filled up to that point. The marking is typically calibrated "to contain" (marked "TC" or "IN") at 20 °C and indicated correspondingly on a label. The flask's label also indicates the nominal volume, tolerance, precision class, relevant manufacturing standard and the manufacturer's logo. Volumetric flasks are of various sizes, containing from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulb Pipette
A volumetric pipette, bulb pipette, or belly pipette allows extremely accurate measurement (to four significant figures) of the volume of a solution. It is calibrated to deliver accurately a fixed volume of liquid. 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 1, 2, 5, 10, 20, 25, 50 and 100 mL. Volumetric pipettes are commonly used in analytical chemistry to make laboratory solutions from a base stock as well as to prepare solutions for titration. ASTM standard E969 defines the standard tolerance for volumetric transfer pipettes. The tolerance depends on the size: a 0.5-mL pipette has a tolerance of ±0.006 mL, while a 50-mL pipette has a tolerance of ±0.05 mL. (These are for Class A pipettes; Class B pipettes are given a tolerance of twice that for the corresponding Class A.) A specialized example of a volumetric pipette is the microfluid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volumetric Pipettes
A volumetric pipette, bulb pipette, or belly pipette allows extremely accurate measurement (to four significant figures) of the volume of a solution. It is calibrated to deliver accurately a fixed volume of liquid. 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 1, 2, 5, 10, 20, 25, 50 and 100 mL. Volumetric pipettes are commonly used in analytical chemistry to make laboratory solutions from a base stock as well as to prepare solutions for titration. ASTM standard E969 defines the standard tolerance for volumetric transfer pipettes. The tolerance depends on the size: a 0.5-mL pipette has a tolerance of ±0.006 mL, while a 50-mL pipette has a tolerance of ±0.05 mL. (These are for Class A pipettes; Class B pipettes are given a tolerance of twice that for the corresponding Class A.) A specialized example of a volumetric pipette is the microfluid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chuck (engineering)
A chuck is a specialized type of clamp used to hold an object with radial symmetry, especially a cylinder. In a drill, a mill and a transmission, a chuck holds the rotating tool; in a lathe, it holds the rotating workpiece. Chucks commonly use jaws to hold the tool or workpiece. The jaws (sometimes called dogs) are typically arranged in a radially symmetrical pattern like the points of a star. Jawed chucks may require a wrench-like device called a ''chuck key'' to be tightened or loosened, but other jawed chucks may be tightened or loosened by hand force alone, offering convenience at the expense of gripping force. Chucks on some lathes have jaws that move independently, allowing them to hold irregularly shaped objects. More complex designs might include specially shaped jaws, greater numbers of jaws, or quick-release mechanisms. Instead of jaws, a chuck may use magnetism, vacuum, or collets, which are flexible collars or sleeves that fit closely around the tool or work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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