In the 1930s, vitamin research indicated that several vitamins, particularly vitamin A, absorb ultraviolet (UV) light. Spurred by the American government’s interest in measuring vitamin content in soldiers’ rations using ultraviolet and visible (UV-Vis) light, this research culminated in the commercial launch of UV-Vis spectrophotometers in the early 1940s. Of these, the Beckman DU spectrophotometer—first sold in 1941— distinguished itself from competing products by delivering more accurate results and reducing analysis time from hours, or even weeks, to minutes.
Although modern UV-Vis spectrometers differ greatly from the first DUs, all operate on the same basic principle. Light intensity is measured from UV-Vis source lamps before and after the light passes through a sample. The amount of light absorbed corresponds to the molecular concentration in the sample.
Whether as standalone instruments or high performance liquid chromatography (HPLC) detectors, UV-Vis spectrophotometers are indispensible for measuring analyte concentrations—in scientific research, academic teaching, and QA/QC laboratories studying pharmaceuticals, proteins, DNA, solar panels, semiconductors, and coatings. New instrument designs and accessories have expanded the range of UV-Vis samples— from liquids traditionally measured in milliliter volumes in 1-cm cuvettes to today’s micro volume.
Nobel laureate Bruce Merrifield referred to the UV-Vis spectrophotometer as “probably the most important instrument ever developed toward the advancement of bioscience.”
In 1935, Arnold O. Beckman founds National Technologies Laboratories—later named Beckman Instruments.
The first commercially available UV-Vis spectrophotometers are introduced. In 1940, Beckman and colleagues at National Technologies Laboratories make their first laboratory spectrophotometer. Howard H. Cary, who leads the project, would later form the Cary Instrument Company.
In 1941, Beckman introduces the DU UV-Vis spectrophotometer, which has higher resolution and lower stray light in the ultraviolet region than any other commercial instrument.
In 1946, Cary Instruments is founded by Howard Cary, George W. Downs, and William C. Miller under the name Applied Physics Corporation. Previously, Howard Cary was vice president in charge of development for Beckman Instruments.
In 1947, Applied Physics Corporation delivers the first commercially available recording UV-Vis spectrophotometer, the Cary 11, to the Mellon Institute in Pittsburgh, PA.
1950s – 1970s Mass production reduces the cost of UV-Vis spectrophotometers. New photodiode arrays collect all wavelengths simultaneously, reducing the time required to scan a spectrum from minutes to seconds. In 1950, National Technologies Laboratories changes its name to Beckman Instruments, Inc.
In 1953, Bausch & Lomb introduces the SPECTRONIC 20 UV-Vis spectrophotometer, the first massproduced, low-cost UV-Vis spectrophotometer.
In 1954, Applied Physics Corporation launches the Cary 14 spectrophotometer, the first commercially available double-beam spectrophotometer. The doublebeam design greatly simplifies and speeds up sample analysis by simultaneously measuring sample and solvent transmittance over the wide spectral range of ultraviolet, visible, and near infrared wavelengths.
In 1963, JASCO introduces the ORD\UV-5 with double-beam UV-Vis capabilities.
In 1966, Applied Physics Corporation is purchased by Varian Medical Systems, becoming the Cary Instruments division of Varian.
In 1969, Cecil Instruments introduces the CE 212, the world's first commercially available variable wavelength detector for HPLC, allowing users to select—without changing filters or lamps—detection wavelengths on a single detector.
In 1979, Hewlett-Packard launches the first commercially available diode-array spectrophotometer, the 8450A. Unlike traditional scanning spectrophotometers with a single photomultiplier tube that scans one wavelength at a time, the 8450A utilizes an array of photodiodes to scan simultaneously the full spectrum of wavelengths in seconds.
The proliferation of personal computers in the 1980s improves data acquisition and instrument control. In 1980, Bausch & Lomb introduces the Spectronic 2000 UV-Vis spectrophotometer, the first microprocessor-controlled double-beam UV-Vis spectrophotometer. Now, instead of measuring sample and solvent transmittance separately, which the single-beam spectrophotometers required, the double-beam design greatly simplifies and speeds up sample analysis by simultaneously measuring sample and solvent transmittance.
In 1987, Pye Unicam Corporation. introduces the PU-8700 UV-Vis spectrophotometer, the first mouse-driven, graphical interface UV-Visible spectrophotometer.
In 1989, Dr. Arnold O. Beckman, now 88 years old, receives the National Medal of Science for his leadership in analytical instrumentation development.
1990s, External software now provides PC control, onscreen spectra display, and spectra reprocessing and storage. Fiber optics reduce instrument size, and fiber optic sampling accessories allow sample measurement outside the UV-Vis spectrophotometer’s sample compartment, eliminating the need to fill sample cells and cuvettes.
In 1995, Hewlett-Packard launches the 8453A, the first small-footprint and full-featured diode-array spectrophotometer.
In 1997, Beckman Instruments, Inc. acquires Coulter Corporation, the leading manufacturer of systems for blood and cell analysis. In 1998, the company is renamed Beckman Coulter, Inc.
In 1999, Hewlett-Packard announces a strategic realignment to create an independent measurement company, Agilent Technologies.
2000s, Significant progress is made in the ability to measure micro volume liquid samples (< 1 μL) in biotechnology and pharmaceutical applications. UV-Vis spectroscopy is applied to alternative energy R&D such as solar energy. Instrument manufacturers start to miniaturize instruments and develop dedicated instruments for specific applications, such as biological applications.
In 2000, Thermo Scientific introduces the GENESYS 10 instruments with out-of-plane optics that minimize stray light and reduce noise caused by instrument optics.
In 2002, Varian Inc. releases the 6000i UV-Vis-NIR spectrophotometer. The Cary 6000i uses an InGaAs detector that improves signal-tonoise ratio over conventional lead sulfide detectors. Its operating range of 175 nm to 1800 nm is applicable to materials science research.
In 2003, Thermo Scientific introduces the Evolution 300 spectrophotometer, the first double-beam xenon lamp-based spectrophotometer. The double-beam design simplifies and speeds up sample analysis. Xenon flash lamps provide a high-energy light source with a shorter warm up time and longer lamp life than traditional tungsten and deuterium lamps.
In 2004, Shimadzu introduces the SolidSpec-3700/3700DUV series of UV-Vis-NIR spectrophotometers, the first UV-Vis-NIR spectrophotometer with three detectors—a photomultiplier for the UVVis region, and an InGaAs detector and a cooled PbS detector for the NIR region.
In 2005, the NanoDrop ND-1000 UV-Vis spectrophotometer (from NanoDrop Technologies) for micro-quantitation of only 1 μl of sample enters the market. The sample is directly pipetted onto a fiber optic measurement surface where it is held in place by surface tension, eliminating the need for cuvettes or capillaries.
In 2006, JASCO manufactures a new range of UV-Vis-NIR spectrophotometers with compatible accessories for life sciences, materials analysis, and semiconductor R&D.
In 2008, Shimadzu launches the UV- 1800 compact UV-Vis spectrophotometer. It occupies a 15% smaller footprint than the model it replaces, the UV-1700.
Also in 2008, Perkin Elmer releases the LAMBDA Bio UV-Vis spectrophotometer pre-configured with standard methods for biological applications including protein assays, cell density measurements, as well as DNA, RNA, and oligonucleotides concentration and purity.
In 2010, Agilent Technologies acquires Varian Inc. and continues to offer the Cary spectrophotometer series under the Cary name.
Also in 2010, Thermo Scientific introduces the Evolution 200 Series spectrophotometer. Its application-focused beam geometry tailors the instrument's optical system to specific applications for microcells, solid sampling, and fiber optics.
Also in 2010, JASCO offers the SAH-769 One Drop accessory to measure micro volume samples of proteins and nucleic acids with UVVis spectrophotometers.
In 2011, Agilent Technologies releases the Cary 60 UV-Vis spectrophotometer with low cost of ownership—the xenon lap typically lasts 10 years—and remote sampling options that minimize sample handling.
Future of UV-Vis Spectrophotometers
Future improvements in UV-Vis spectrophotometers will focus on ease-of-use, portability, and application-specific instruments. UV-Vis analysis of solid samples and materials continues to grow in areas such as solar cell research, semiconductor products, and coating materials. Advances in light sources will provide new developments in conventional spectrophotometers and handheld UV-Vis instruments. Further development in remote sensors will enable more types of samples to be measured outside the laboratory.