spectrophotometer
(ˌspɛktrəfəʊˈtɒmɪtə(r))
[f. spectro- + photometer.]
An instrument designed to measure the relative intensity of light (usu. transmitted or emitted by a substance under study) at different wavelengths in a particular region of the spectrum.
| 1881 Nature XXIV. 552 Photometric comparison of luminous sources of different colours, by M. Crova. He uses a spectrophotometer. 1938 Jrnl. Optical Soc. Amer. XXVIII. 18 This spectrophotometer was designed specifically to measure in the visible region the absorption spectrum of visual purple. 1948 Nature 21 Feb. 285/2 Total penicillin may be assayed non-biologically with the aid of the..ultra-violet spectrophotometer. 1966 McGraw-Hill Encycl. Sci. & Technol. II. 594 d/1 The split-beam spectrophotometer..measures the difference in absorption at any given wavelength between two nearly identical cell suspensions. 1976 C. Skegg tr. Welz's Atomic Absorption Spectroscopy v. 84 In modern spectrophotometers a logarithmization of the signal takes place within the instrument, so that the readout on the display is already in absorbance and no conversion is required. |
Hence ˌspectrophotoˈmetric a., of, pertaining to, or employing a spectrophotometer; ˌspectrophotoˈmetrically adv.; spectrophoˈtometry, the technique of using a spectrophotometer.
| 1884 Boston (Mass.) Jrnl. 13 Sept., A ‘spectrophotometric study of pigments’, by Professor Nicolls. 1897 Allbutt's Syst. Med. IV. 285 Normal fresh urines..examined spectro-photometrically. 1899 Phil. Mag. XLVIII. 421 In direct comparisons of white light this latter principle has been successfully applied; but in spectrophotometry the optical difficulties in the way of its use have prevented the obtaining of corresponding results. 1942 Astrophysical Jrnl. XCVI. 451 Spectrophotometric observations of the light of the night sky have been made for the stronger lines of the visual region of the spectrum. 1961 Times 9 Jan. 2/3 (Advt.), The Physical Assay Division..is concerned..with..application of industrial methods of analysis including ultraviolet and infra-red spectrophotometry. 1972 R. A. Jackson Mechanism iv. 76 If the reaction is followed spectrophotometrically the presence or absence of stable intermediates is often indicated from the changes in the spectrum as the reaction proceeds. 1976 G. Thurston Coronership i. 13 Methods of analysis by chromatography and spectrophotometry enable accurate results to be produced with speed. 1977 I. M. Campbell Energy & Atmosphere ix. 307 (caption) Concentration profile of O2..versus altitude in the upper mesosphere, measured by rocket-borne spectrophotometric detection. |