GENERAL ELECTRIC - ACS Publications - American Chemical Society

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H O W G.E.'S RECORDING SPECTROPHOTOMETER HELPS YOU

Identify Colorants Quickly and Accurately GA E x t r a C o n c e n t r a t e d (C. I . 31). T h a t curve is shown as t h e solid line on t h e Suppose t h a t d u r i n g a check of mill in­ g r a p h . I t is also possible t o read t h e con­ v e n t o r y you find a barrel of dye m a r k e d c e n t r a t i o n of t h e sample dye directly b y " R e d G . " E x a c t identification a n d placing a simple plastic scale over t h e s t r e n g t h are u n k n o w n b u t t h e sample is curves t o find concentration difference k n o w n t o be an acid dye. W i t h o u t spend­ between t h e known concentration and ing a lot of t i m e on complex q u a n t i t i v e t h e u n k n o w n . a n d q u a l i t a t i v e analysis, you can identify t h e dye quickly a n d accurately, and read t h e concentration directly b y t h e use of a simple plastic scale.

PROBLEM 1

HERE'S HOW Dissolve t h e d y e in w a t e r a n d place t h e sample in a General Electric Record­ ing S p e c t r o p h o t o m e t e r . T h e i n s t r u m e n t draws a curve which is characteristic of t h e color of t h e sample. This curve, shown in red, is t h e "fingerprint" of t h e d y e which you are t r y i n g t o identify a n d b y checking this curve with y o u r file of curves for other dyes of this t y p e , y o u r u n k n o w n dye can be identified quickly a n d accurately. I n t h e example pictured OPERATOR RUNNING CURVE of a color sample here, t h e curve was readily seen t o m a t c h on the General Electric's easy-to-use Record­ t h e "fingerprint" curve of Azo Phloxine ing Spectrophotometer.

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SCALE SHOWS sample is 10% weaker than known standard of Azo Phloxine GA Extra Cone. (C. I. 31).

Color-match Samples Without Question in t h e orange region. You t h e n mix t h e REFLECTANCE dyes, m a k e a trial dyeing and r u n another Suppose a customer sends you a sample curve. This curve will m a t c h t h e original of a grey shade and asks you t o develop curve a n d only slight formula adjust­ a dye t o m a t c h it. T h e General Electric m e n t s will be needed t o get an exact Recording Spectrophotometer will help visual m a t c h . T o t a l t i m e 10-15 m i n u t e s . you avoid t h e delay of m a n y trial a n d error formulations a n d will give you A c o l o r - m e a s u r e m e n t s course will be guidance in preparing a formula which held in N e w E n g l a n d this s u m m e r . F o r will not change color when going from information on t h e course or a b o u t t h e spectrophotometer call y o u r G - E Appa­ one t y p e of illumination t o a n o t h e r . r a t u s Sales Office or write t o Section 585-40, G e n e r a l Electric C o m p a n y , HERE'S HOW Schenectady, Ν . Υ . M e a s u r e sample on G - E Spectropho­ t o m e t e r using a color m a t c h i n g " R " cam. T h e resultant curve (red line) has char­ acteristics of t h e curves for orange a n d blue dyes, not of yellow, red and blue dyes. C u r v e s of t h e proper blue d y e .05 (Acid Blue A R A ) (dashed line) a n d for t h e proper orange dye ( F a s t Light Orange 2G) ( d o t t e d line) are shown. Use of a simple plastic scale will show t h e proper .OIL 400 450 500 550 G00 650 700 concentration for t h e blue dye a n d t h e CURVE OF UNKNOWN SAMPLE indicated in a m o u n t of orange dye can be easily calcu­ CLOSE-UP of the General Electric Spectro­ red. Curve shape indicates that blue and lated allowing for t h e absorption of blue photometer drawing a curve of color. orange dyes should be used.

PROBLEM 2

GENERAL

ELECTRIC

For further information, circle numbers 61 A - 1 , 61 A-2 on Readers' Service

VOLUME

2 8 , N O . 7, J U L Y

1956

Card, page 51 A

61 A