Editing Laboratory glassware (section)

===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>