20 A
ANALYTICAL
CHEMISTRY
NEW MODEL Β
BECKMAN SPECTROPHOTOMETER SCHEDULED
FOR PRODUCTION,
APRIL,
1949
9091-A
GLASS PRISM SPECTROPHOTOMETER, Beckman Model B. A new, medium priced instru ment designed especially for speed and convenience in routine analyses but with an accuracy suitable for many types of research work. Range 320 to 700 mmu with standard blue-sensitive phototube and, by the use of an accessory red-sensitive phototube, up to 1,000 mmu. Consisting of a glass prism monochromator with tungsten lamp light source, holder with four cells, blue-sensitive phototube, built-in a.c. operated voltage stabilized amplifier, and indicating meter reading directly in both absorbance (optical density) and percentage transmission. Monochromator. With glass prism. Wavelength scale approx. 260 m m long, graduated from 320 to 1,000 mmu, readable and reproducible to 0.5 mmu in the ultraviolet, to 1 mmu in the visible range and to 2 mmu in the near infrared, with an absolute accuracy within 5 mmu. Stray light is negligible, i.e., less than 1.5% at the extreme violet end of the spectrum. Minimum spectral band width less than 5 mmu between 320 and 600 mmu, and 6 to 7 mmu between 600 and 700 mmu. Wavelength scale is at top of sloping panel and is operated by control knob at front of instrument. Slits. Entrance and exit slits are simultaneously adjust able by graduated control on front of panel. Meter. A large deflection type meter, with mirror to avoid parallax, permits direct readings of absorbance (optical density) or percentage transmission, with an
accuracy of 1% absorbance and 0.5% transmission. A four-position amplifier sensitivity control on the front panel shifts absorbance readings in 0.500 unit steps, per mitting readings on the upper two-thirds of the meter scale where it is expanded. Sample Holders. The cell carrier is designed to take either a standard holder with four square cells 10 mm liquid length or two cylindrical cells up to 50 mm length. The entire cell carrier assembly can be removed from the instrument and replaced with an Integrating Sphere Re flectance Attachment, for either solid or powdered samples, which will be available later. Phototubes. A blue-sensitive phototube, which covers the range 320 to 700 mmu, is furnished with the instru ment. An accessory red-sensitive phototube is offered for extending the range to 1,000 mmu.
9091-A.
Spectrophotometer, Glass Prism, Beckman Model B, range 320 to 700 mmu, as above described, consisting of monochromator with glass prism and two slits; blue-sensitive phototube; holder with set of four square cells, 10 mm liquid length; voltage stabilized amplifier for operation on 115 volts, 60 cycles, a . c ; and 6-volt tungsten lamp for operation from a storage battery but without battery 585.00
9091-C.
Ditto, but with external constant voltage transformer for operation of both the tungsten lamp and amplifier from 115 volts, 60 cycles, a . c , eliminating the necessity for a 6-volt storage battery 609.00
ARTHUR H. THOMAS COMPANY RETAIL—WHOLESALE—EXPORT
LABORATORY APPARATUS AND REAGENTS WEST WASHINGTON SQUARE, PHILADELPHIA 5, PA., U.S.A.
C^ble Address "Balance," Philadelphia
