Laboratory glassware is a variety of equipment used inscientific work, traditionally made ofglass. Glass may be blown, bent, cut, molded, or formed into many sizes and shapes. It is commonly used inchemistry,biology, and analyticallaboratories. Many laboratories have training programs to demonstrate how glassware is used and to alert first–time users to thesafety hazards involved with using glassware.
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The history of glassware dates back to thePhoenicians who fusedobsidian together incampfires, making the first glassware. Glassware evolved as other ancient civilizations including the Syrians, Egyptians, and Romans refined the art of glassmaking.Mary the Jewess, an alchemist in Alexandria during the 1st century AD, is credited for the creation of some of the first glassware for chemical such as thekerotakis which was used for the collection of fumes from a heated material.[1] Despite these creations, glassware for chemical uses was still limited during this time because of the low thermal stability necessary for experimentation, so equipment was primarily made usingcopper orceramic materials instead.[1]
Glassware improved once again during the 14th-16th century, with the skill and knowledge of glass makers inVenice. During this time, the Venetians gathered knowledge about glassmaking from the East with information coming fromSyria and theByzantine Empire.[1] Along with knowledge about glassmaking, glassmakers in Venice also received higher quality raw materials from the East such as imported plant ash which contained higher soda content compared to plant ash from other areas.[1] This combination of better raw materials and information from the East led to the production of clearer and higher thermal and chemical durability leading towards the shift to the use of glassware in laboratories.[1]
Many glasses that were produced in bulk in the 1830s would quickly become unclear and dirty because of the low quality glass being used.[2]During the 19th century, more chemists began to recognize the importance of glassware due to its transparency, and the ability to control the conditions of experiments.[3]Jöns Jacob Berzelius, who invented thetest tube, andMichael Faraday both contributed to the rise of chemical glassblowing. Faraday publishedChemical Manipulation in 1827 which detailed the process for creating many types of small tube glassware and some experimental techniques for tube chemistry.[3][4] Berzelius wrote a similar textbook titledChemical Operations and Apparatus which provided a variety of chemical glassblowing techniques.[3] The rise of this chemical glassblowing widened the availability of chemical experimentation and led to a shift towards the dominant use of glassware in laboratories. With the emergence of glassware in laboratories, the need for organization and standards arose. ThePrussian Society for the Advancement of Industry was one of the earliest organizations to support the collaborative improvement of the quality of glass used.[5]
Following the development ofborosilicate glass byOtto Schott in the late 19th century, most laboratory glassware was manufactured in Germany up until the start ofWorld War I.[6] Before World War I, glass producers in the United States had difficulty competing with German laboratory glassware manufacturers because laboratory glassware was classified as educational material and was not subject to an import tax. During World War I, the supply of laboratory glassware to the United States was cut off.[6]
In 1915Corning Glassworks developed their own borosilicate glass, introduced under the namePyrex. This was a boon to the war effort in the United States.[6] Though many laboratories turned back to imports after the war ended, research into better glassware flourished. Glassware became more resistant tothermal shock while maintainingchemical inertness.[7]
During the 1920s efforts tostandardise the dimensions of laboratory glassware began, particularly forground glass joints, with some manufacturer specific standardisation beginning to occur around this time. Commercial standards began development around 1930, allowing the compatibility of joints between different manufacturers for the first time, along with other features.[8][9] This quickly led to the high degree of standardisation andmodularity seen in modern glassware.
Laboratory glassware is typically selected by a person in charge of a particular laboratory analysis to match the needs of a given task. The task may require a piece of glassware made with a specific type of glass. The task may be readily performed using low cost,mass-produced glassware, or it may require a specialized piece created by aglass blower. The task may require controlling the flow offluid. The task may have distinctive quality assurance requirements.
Laboratory glassware may be made from several types ofglass, each with different capabilities and used for different purposes.Borosilicate glass is a type of transparent glass that is composed of boron oxide and silica, its main feature is a low coefficient of thermal expansion making it more resistant to thermal shock than most other glasses.[10]Quartz glass can withstand very high temperatures and is transparent in certain parts of theelectromagnetic spectrum. Darkened brown or amber (actinic) glass can blockultraviolet andinfrared radiation. Heavy-wall glass can withstand pressurized applications.Fritted glass is finely porous glass through which gas or liquid may pass. Coated glassware is specially treated to reduce the occurrence of breakage or failure.Silanized (siliconized) glassware is specially treated to prevent organic samples from sticking to the glass.[11]
Scientific glass blowing, which is practiced in some larger laboratories, is a specialized field of glassblowing. Scientific glassblowing involves precisely controlling the shape and dimension of glass, repairing expensive or difficult-to-replace glassware, and fusing together various glass parts. Many parts are available fused to a length ofglass tubing to create highly specialized piece of laboratory glassware.
When using glassware it is often necessary to control the flow of fluid. It is commonly stopped with astopper. Fluid may be transported between connected pieces of glassware. Types of interconnecting components includeglass tubing, T-connectors, Y-connectors, and glass adapters. For a leak-tight connection aground glass joint is used (possibly reinforced using a clamping method such as aKeck clips). Another way to connect glassware is with ahose barb and flexibletubing. Fluid flow can be switched selectively using avalve, of which astopcock is a common type fused to the glassware. Valves made entirely of glass may be used to restrictfluid flows. Fluid, or any material which flows, can be directed into a narrow opening using afunnel.
Laboratory glassware can be used for high precision volumetric measurements. With high precision measurements, such as those made in a testing laboratory, themetrological grade of the glassware becomes important. The metrological grade then can be determined by both theconfidence interval around the nominal value of measurement marks and the traceability of the calibration to an NIST standard. Periodically it may be necessary to check the calibration of the laboratory glassware.[12]
Laboratory glassware is composed of silica, which is consideredinsoluble in most substances, with a few exceptions such ashydrofluoric acid or strongalkali hydroxides. Though insoluble, a minute quantity of silica willdissolve in neutral water, which may affect high precision, lowthreshold measurements of silica in water.[13]
Cleaning laboratory glassware is a frequent necessity and may be done using multiple methods depending on the nature of the contamination and the purity requirements of its use. Glassware can be soaked in a detergent solution to remove grease and loosen most contaminations, these contaminations are then scrubbed with a brush or scouring pad to remove particles which cannot be rinsed. Sturdy glassware may be able to withstandsonication as an alternative to scrubbing. Solvents are used to remove organic residues that soap cannot remove, and inorganic residues that do not dissolve in water can often be dissolved with a dilute acid. When cleaning is finished it is common practice to rinse glassware multiple times, often finally withdeionised water, before suspending it upside down on drying racks.[14] Specialised dishwashers can be used to automate these cleaning methods.
Resistant residues may require more powerful cleaning methods. Base baths are commonly used for organic residues, although the strong alkaline conditions do slowly dissolve the glass itself, and concentratedhydrochloric acid is common for removing inorganic residues.[15] Even more severe methods exist, such as acidic peroxide (piranha solution),aqua regia, andchromic acid, but these are considered somewhat of a last resort due to the hazards of using them, and their use by students is restricted in many institutions.[14]
For certain sensitive experiments glassware may require specialised procedures and ultra-pure water or solvents to dissolve trace quantities of specific contaminations known to interfere with an experiment.[16]
There are many different kinds of laboratory glassware items:
Examples of glassware containers include:
Examples of glassware used for measurements include:
Other examples of glassware includes:
