approved

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approved

total organic carbon volatile organic carbon total carbon T H E D O H R M A N N » DC-50 ORGANIC ANALYZER makes all of these measurements accurately and rapidly. Based on proven, E P A approved* methods, it avoids interferences and undesirable pyrolysis reactions that historically have resulted in significant errors. • D I R E C T R E A D O U T : Four-digit presentation shows carbon content directly in mg/liter or ppm. iVo recorder needed! • D I R E C T M E A S U R E M E N T : A single sample injection gives either Organic Carbon or Total Carbon content directly, not by difference. • INDEPENDENT MEASUREMENT: Volatile Organics are determined separately from T o t a l Organics to aid in source identification. • RELIABLE M E A S U R E M E N T S : Determines important, lightweight volatiles such as low molecular weight alcohols and ketones, normally lost by acidification and sparging. • F A S T : S minutes per determination. • ACCURATE: Repeatability of ± 1 m g / liter or ± 2 % . • W I D E R A N G E : 1 to 2,000 mg/liter (ppm) without dilution. • P R I C E : $7,875, including start-up assistance and operator training. ENVIRONMENTAL PROTECTION AGENCY, WATER P R O G R A M S , G u i d e l i n e s E s t a b l i s h i n g T e s t Procedures for Analysis of Pollutants. F E D E R A L R E G I S T E R Vol. 38, No. 199, Part II, Oct. 16, 1973. For brochures, reprints, or dates and locations of seminars, contact: D O H R M A N N DIVISION, 3240 Scott Blvd., Santa Clara, CA 95050. (408) 249-6000. Telex 346 395.

New Products

Molecular Weight Apparatus T h e a p p a r a t u s m a k e s it possible t o d e t e r m i n e t h e molecular weights of a n y nonvolatile m a t e r i a l which can be dissolved in a volatile solvent, d e t e r m i n e t h e conc e n t r a t i o n of a solution w h e n t h e solute molecular weight is known, a n d also d e t e r m i n e activity coefficients. T h e i n s t r u m e n t works on t h e differential vaporp r e s s u r e principle in which two carefully m a t c h e d t h e r m i s t o r s are placed in a c h a m b e r which is carefully s a t u r a t e d w i t h solvent vapor. R e s p o n s e t i m e for this m e t h o d which results in excellent reproducibility a n d sensitivity is 5 t o 7 m i n . W e s c a n I n s t r u m e n t s , Inc. 408

Secondary Ion Mass Spectrometer

Quantitative Polarizing Microscope

T h e secondary ion m a s s s p e c t r o m e t e r developed b y G.S.F. in N e u g e r b e r g , W e s t G e r m a n y , h a s recently b e e n d e m o n s t r a t e d with raster scanning of a small d i a m e t e r ion b e a m . Surface imaging w i t h a C R T display c o n v e r t s t h e i n s t r u m e n t into a s c a n n i n g ion m i croscope priced well below convent i o n a l ion microscopes. E x t r a n u c l e a r L a b o r a t o r i e s , Inc. 409

T h e M P - 1 2 0 polarizing microscope, by J a m e s Swift & Son Ltd., is designed specifically for t h e mineralogist, petrologist, a n d chemical microscopist. A direct optical system dispenses w i t h deviating p r i s m s resulting in perfect objective-eyepiece c o m b i n a t i o n , m a x i m u m t r a n s m i s s i o n , s u p e r b image c o n t r a s t a n d clarity, a n d n o depolarization effects. A p p r o x i m a t e l y $2000. H a c k e r I n s t r u m e n t s Inc. 407

Data Tape Cassette Recorder M o d e l M S Y - 2 6 , specifically designed for use with c h r o m a t o g r a p h - t y p e e q u i p m e n t , provides a n efficient m e a n s of gathering, storing, a n d rep r o d u c i n g c h r o m a t o g r a p h signals. D a t a can be recorded a t a r e m o t e location a n d played back t h r o u g h a comp u t e r i z e d d a t a r e d u c t i o n center, providing excellent q u a l i t y d a t a . T h e M S Y - 2 6 c o n t a i n s a low-level differential p r e a m p , a VCO m o d u l e , a cassette t a p e r e c o r d / r e p r o d u c e r , a discriminator, a n d a filter amplifier. $1450. D a l las I n s t r u m e n t s , Inc. 419

ENVIROTECH For more information on listed items, circle the appropriate numbers on one of our Readers' Service Cards CIRCLE 66 ON READER SERVICE CARD 1298 A · ANALYTICAL CHEMISTRY, VOL. 47, NO. 14, DECEMBER 1975