GB856442A - Improvements in flame spectrophotometry - Google Patents

Abstract

856,442. Photo-electric spectrometers. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Dec. 31, 1958 [Jan. 13, 1958], No. 1240/58. Class 40(3). In a flame spectrophotometer in which the burner aspirates a liquid whose spectrum is to be studied, the presence of the liquid is arranged to complete a circuit between a conducting aspirating tube and a further electrode to control the integration of the spectro-photometer output. Figs. 2 and 3 show the burner arrangement. The liquid under test is placed in a small vessel in a holder A. When handle D is released from one end of a bayonet slot, a spring C forces the holder A upwardly so that the operating tube N and an electrode L mounted on an insulating block K dip into the liquid. The conductive path thus completed between them causes a triode V5 to conduct operating a relay 30 which completes an integrating circuit for the output of the light sensitive device. This integration commences as soon as the liquid is drawn into the aspirating tube by combustion gas introduced to the burner at tubes 24, 25. The Specification describes an arrangement, (Fig. 4 not shown) whereby a known spectrophotometer containing both a photo-multiplier and a red sensitive cell is modified to allow the light sensitive device to be corrected to charge one or other of a pair of condensers, integration being initiated by the operation of relay 30 which connects the output of the light sensitive device to the condenser. A switch 5 provided so that one condenser may be charged by a standard sample and another by the liquid under test. The two condensers may be discharged in opposition and the time taken for the difference to fall to some predetermined valve measured.