Editing Laboratory glassware (section)

==Laboratory glassware selection==
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 a [[Scientific glassblowing|glass blower]].  The task may require controlling the flow of [[fluid]].  The task may have distinctive quality assurance requirements.

===Type of glass===
[[File:Verrerie-p1030903.jpg|thumb|left|Brown glass jars with some clear lab glassware in the background]]
Laboratory glassware may be made from several types of [[glass]], 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.<ref>{{Cite journal |last=Soo-Jin Park |first=Min-Kang Seo |date=2011 |title=Element and Processing |url=https://www.sciencedirect.com/topics/chemistry/borosilicate-glass#:~:text=Borosilicate%20glass%20is%20a%20type,than%20any%20other%20common%20glass. |journal=Interface Science and Technology |volume=18 |pages=431–499|doi=10.1016/B978-0-12-375049-5.00006-2 |isbn=9780123750495 }}</ref> [[Quartz glass]] can withstand very high temperatures and is transparent in certain parts of the [[electromagnetic spectrum]].  Darkened brown or amber (actinic) glass can block [[ultraviolet]] and [[infrared]] 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. [[Silanization|Silanized]] (siliconized) glassware is specially treated to prevent organic samples from sticking to the glass.<ref name="Siliconized">{{cite journal|last1=Bhargava|first1=Hemendra|title=Improved Recovery of Morphine from Biological Tissues Using Siliconized Glassware|journal=Journal of Pharmaceutical Sciences|date=1977|volume=66|issue=7|pages=1044–1045|doi=10.1002/jps.2600660738|pmid=886442}}</ref>

===Scientific glass blowing===
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 of [[glass tubing]] to create highly specialized piece of laboratory glassware.

===Controlling fluid flow===
When using glassware it is often necessary to control the flow of fluid.  It is commonly stopped with a [[Bung|stopper]]. Fluid may be transported between connected pieces of glassware.  Types of interconnecting components include [[glass tubing]],  T-connectors, Y-connectors, and glass adapters.  For a leak-tight connection a [[ground glass joint]] is used (possibly reinforced using a clamping method such as a [[Keck clips]]).  Another way to connect glassware is with a [[hose barb]] and flexible [[Tube (fluid conveyance)|tubing]]. Fluid flow can be switched selectively using a [[valve]], of which a [[stopcock]] is a common type fused to the glassware. Valves made entirely of glass may be used to restrict [[fluid]] flows. Fluid, or any material which flows, can be directed into a narrow opening using a [[Funnels (laboratory)|funnel]].

{{Gallery
|title=Controlling fluid flow with specific glassware
|width=160 | height=170
|align=center
|footer= 
|File:All Glass Check Valve.jpg
 |alt1=An all-glass check valve.
 |An all-glass check valve.
|File:Erlenmeyer and Filtering Flask.jpg
 |alt2=An Erlenmeyer and a filtering flask.
 |An Erlenmeyer and a filtering flask. Note the barbed sidearm on the filtering flask.
|File:Glass adapter with barbed end and ground glass fitting.jpg
 |alt3=A glass adapter. 
 |A glass adapter with a hose barb on the left and a ground glass connector on the right.
|File:Glindemann PTFE Sealing Ring for Taper Joint Glassware.JPG
 |alt4=A taper joint stopper with PTFE sealing ring.
 |A taper joint stopper with [[PTFE]] sealing ring. Note the optical transparency of the narrow sealing ring pressured by glass joint on the right.
|File:T bore plug.JPG
 |alt5=A thread T-bore plug valve
 |A thread T-bore plug valve used as a side arm on a [[Schlenk flask]].
|File:Sidearm stockcock.JPG
 |alt6=A common straight bore glass stopcock attached with a plastic plug retainer 
 |A common straight bore glass [[stopcock]] attached with a plastic plug retainer in the side arm of a [[Schlenk flask]].
}}

===Quality assurance===
====Metrology====
Laboratory glassware can be used for high precision volumetric measurements. With high precision measurements, such as those made in a testing laboratory, the [[Metrology|metrological]] grade of the glassware becomes important.  The metrological grade then can be determined by both the [[confidence 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.<ref name="metrology">{{cite journal|last1=Castanheira|first1=I.|title=Quality assurance of volumetric glassware for the determination of vitamins in food|journal=Food Control|date=2006|volume=17|issue=9|pages=719–726|doi=10.1016/j.foodcont.2005.04.010}}</ref>

====Dissolved silica====
Laboratory glassware is composed of silica, which is considered [[insoluble]] in most substances, with a few exceptions such as [[hydrofluoric acid]] or strong [[alkali hydroxide]]s. Though insoluble, a minute quantity of silica will [[Dissolution (chemistry)|dissolve]] in neutral water, which may affect high precision, low [[Reference range|threshold]] measurements of silica in water.<ref name="silica_dissolution">{{cite journal|last1=Zhang|first1=Jia-Zhong|title=Laboratory glassware as a contaminant in silicate analysis of natural water samples|journal=Water Research|date=1999|volume=33|issue=12|pages=2879–2883|doi=10.1016/s0043-1354(98)00508-9|doi-access=free}}</ref>

====Cleaning====
[[File:Caricamento della vetreria di laboratorio in lavastoviglie.jpg|thumb|right|Cleaning laboratory glassware in a dishwasher]]
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 withstand [[sonication]] 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 with [[Purified water|deionised water]], before suspending it upside down on drying racks.<ref name=":3">{{Cite web |title=How To |url=https://www.chem.rochester.edu/notvoodoo/pages/how_to.php?page=clean_glassware |access-date=2024-08-06 |website=www.chem.rochester.edu}}</ref>  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 concentrated [[hydrochloric acid]] is common for removing inorganic residues.<ref>{{Cite web |date=6 August 2024 |title=Base bath standard operating procedure |url=https://ehs.umass.edu/sites/default/files/Base%20Baths%20SOP.pdf |url-status=live |archive-url=https://web.archive.org/web/20230927032845/https://ehs.umass.edu/sites/default/files/Base%20Baths%20SOP.pdf |archive-date=27 September 2023 |access-date=6 August 2024 |website=University of Massachusetts Amherst}}</ref>  Even more severe methods exist, such as acidic peroxide ([[piranha solution]]), [[aqua regia]], and [[chromic 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.<ref name=":3" />

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.<ref name="cleaning_reagent">{{cite journal|last1=Campos|first1=M.L.A.M.|title=Dissolved organic carbon in rainwater: Glassware decontamination and sample preservation and volatile organic carbon|journal=Atmospheric Environment|date=2007|volume=41|issue=39|pages=8924–8931|doi=10.1016/j.atmosenv.2007.08.017|bibcode=2007AtmEn..41.8924C}}</ref>