Editing Spectrophotometry (section)

==History==
Invented by [[Arnold O. Beckman]] in 1940 {{Disputed inline|date=June 2018}}, the spectrophotometer was created with the aid of his colleagues at his company National Technical Laboratories founded in 1935 which would become Beckman Instrument Company and ultimately [[Beckman Coulter]]. This would come as a solution to the previously created spectrophotometers which were unable to absorb the ultraviolet correctly. He would start with the invention of Model A where a glass prism was used to absorb the UV light. It would be found that this did not give satisfactory results, therefore in Model B, there was a shift from a glass to a quartz prism which allowed for better absorbance results. From there, Model C was born with an adjustment to the wavelength resolution which ended up having three units of it produced. The last and most popular model became Model D which is better recognized now as the [[DU spectrophotometer]] which contained the instrument case, hydrogen lamp with ultraviolet continuum, and a better monochromator.<ref>{{Cite news|url=http://go.galegroup.com/ps/i.do?p=SCIC&id=GALE&#124;A143579063&v=2.1&it=r&sid=SCIC&asid=910964e6|title=The first commercial UV-vis spectrophotometer|last=Ishani|first=G|date=2006|work=[[The Scientist (magazine)|The Scientist]]|access-date=Dec 23, 2018|page=100}}</ref> It was produced from 1941 to 1976 where the price for it in 1941 was [[US$]]723 (far-UV accessories were an option at additional cost). In the words of Nobel chemistry laureate [[Bruce Merrifield]], it was "probably the most important instrument ever developed towards the advancement of bioscience."<ref>{{Cite journal|last1=Simoni|first1=RD|last2=Hill|first2=RL|last3=Vaughan|first3=M|last4=Tabor|first4=H|date=Dec 5, 2003|title=A Classic Instrument: The Beckman DU Spectrophotometer and Its Inventor, Arnold O. Beckman|url=http://www.jbc.org/content/278/49/e1|journal=[[Journal of Biological Chemistry|J. Biol. Chem.]]|volume=278|issue=49|pages=e1|doi=10.1016/S0021-9258(20)75750-9|issn=1083-351X|doi-access=free}}</ref>

Once it became discontinued in 1976,<ref name="Beckman">{{cite journal|last1=Beckman|first1=A. O.|last2=Gallaway|first2=W. S.|last3=Kaye|first3=W.|last4=Ulrich|first4=W. F.|title=History of spectrophotometry at Beckman Instruments, Inc|journal=Analytical Chemistry|date=March 1977|volume=49|issue=3|pages=280A–300A|doi=10.1021/ac50011a001}}</ref> [[Hewlett-Packard]] created the first commercially available diode-array spectrophotometer in 1979 known as the HP 8450A.<ref>{{Cite journal|date=1979-10-01|title=Hewlett Packard: Compound Identification with HP 8450 A UV Visible Spectrophotometer|journal=Analytical Chemistry|volume=51|issue=12|pages=1188A–1189A|doi=10.1021/ac50048a728|issn=0003-2700}}</ref> Diode-array spectrophotometers differed from the original spectrophotometer created by Beckman because it was the first single-beam microprocessor-controlled spectrophotometer that scanned multiple wavelengths at a time in seconds. It irradiates the sample with polychromatic light which the sample absorbs depending on its properties. Then it is transmitted back by grating the photodiode array which detects the wavelength region of the spectrum.<ref>{{Cite book|title=Fundamental Laboratory Approaches for Biochemistry and Biotechnology|last1=Ninfa|first1=Alexander J.|last2=Ballou|first2=David P.|last3=Benore|first3=Marilee|date=2015|publisher=Wiley & Sons|isbn=9780470924525|edition=3, rev.|location=Hoboken, NJ|pages=77|oclc=915641828|name-list-style=vanc}}</ref> Since then, the creation and implementation of spectrophotometry devices has increased immensely and has become one of the most innovative instruments of our time.