COLEMAN INSTRUMENTS

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ANALYTICAL

22 A

CHEMISTRY

Coleman Nepho-Colorimeter FOR

THE

EXACT

MEASUREMENT

OF

COLOR, HAZE

FOR N E P H E L O M E T R Y Nephelometry is the science of evaluating haze in liquids by measuring its ability to reflect light, this ability being directly related to the concentration of the suspended phase. The Model 9 Nepho-Colorimeter is an extremely sensitive and highly precise instrument for measuring this reflected (Tyndall) light. Coleman Certified Nephelos Standards permit expression of such measure­ ments in terms of a fixed, numerical scale. Data thus becomes univetsaliy significant and comparable. Repeated preparation of temporary standards is eliminated. The linear relation between instrument response and Tyndall light intensity makes Nephelos/ Concentration calibtations simple and exact. Nephelometry is finding increasing application in the examination of Biologicals, Bacterial Suspensions, Industrial Waters, Beverages and Blood Sera.

for

Bulletin

TURBIDITY

AB-215

for

full

information.

(MODEL 7)

For Nephelometry only. The Model 7 Photo-Nephelometer is capable of the same precision in nephelometric measurements as the Model 9 Nepho-Colorimeter but is not equipped for Colorimetric or Turbidimetric measurements by transmitted light. for

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A B-214

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LIQUIDS

FOR T U R B I D I M E T R Y When the particles in a liquid suspension are sufficiently con­ centrated to interfere substantially with the transmission of light, the amount of suspended material may be measured by determin­ ing the transmittance of the suspension and relating it to patticle concentration. Turbidity measurements with the Model 9 NephoColorimeter are characterized by the ease and speed of directdeflecrion reading and by the unparalleled precision available from the calibrated potentiometer. Determinations can be made with either white light or colored light.

Coleman Photo-Nephelometer

W r i t e

IN

above that ordinarily available in filter instruments. Selected filters cover the visible spectrum in six uniform increments. Scratch-proof mountings assure continued uniformity. Directreading scales for optical density or percent transmittance read­ ings may be interchanged with scales individually calibrated for specific analytical methods. Interchangeable adapters accept cuvettes ranging from 25mm depth down to capillaries requiring only 0.01ml of solution.

FOR C O L O R I M E T R Y Actuation of a single switch converts the Model 9 Nepho-Color­ imeter from a nephelometer to a precision colorimeter capable of colorimetric measurements of a precision and certainty far Write

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