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New Products Programmable Coulometer Model 3040 programmable potential coulometer can be used with a variety of external cells for electrochemical analysis, monitoring of any portion of an electrochemical reaction, measure ments of elemental concentrations or chemical changes in solution, or, with modifications, other applications nor mally performed by polarography or an odic stripping voltammetry. The instru ment has eight channels of input, each of which can be programmed for time and potential, positive or negative inte gration, differentiation, and power for stirring the cell. The potential can be programmed within zones. It is c o m pletely solid state with an electronically established reference value, nanogram sensitivity, and a system accuracy of ± 5 % . Environmental Sciences Asso ciates, Inc. 408
Chemicals
BUCK Scientific, Inc. Princes Pine Road, West Norwalk, Conn. 06850
Polyamine-Chelated Alkali Metal Compounds A variety of hydrocarbon soluble chelat ed inorganic and organometallic lithium and sodium compounds are available. Stable chelates are formed after certain lithium and sodium compounds react with polydentate tertiary amines such as Λ/,Λ/,Λ/',Λ/'-tetramethylethylenediamine and A/.A/.A/.A/./V'-pentamethyldiethylenetriamine. Alfa Division, Ventron Corp. 421
(203) 853-9444 CIRCLE 23 ON READER SERVICE CARD
SRM's for Forensic Labs
Only this spectrophotometer has (in its price class)... 1. a double-grating monochromator 2. automatic blank reference. It's the Zeiss PM6, and it also features: 3. a choice of different sampling devices 4 . a compact single-unit package. Get full details. Write Carl Zeiss, Inc., 444 5th Ave., New York, N.Y. 10018. Nationwide sales and service.
ZEISS
THE GREAT NAME IN OPTICS
CIRCLE 247 ON READER SERVICE CARD 848 A · ANALYTICAL CHEMISTRY, VOL. 4 8 , NO. 1 1 , SEPTEMBER
1976
Two new Standard Reference Materials are available. SRM 1 8 2 1 , ethanol, is more than 9 9 . 9 % pure and is analyzed for water and certain organic c o m pounds. SRM 1821 is furnished in units of 12 sealed ampuls, each containing 10 ml of ethanol ($57/unit). S"RM 1823, refractive index silicone liquids, con sists of two silicone liquids that are thermally and chemically stable over a wide temperature range. The liquids span the refractive index range of a va riety of glasses and fibers that are ex amined by means of immersion tech niques. They are certified for refractive indexes at 10 wavelengths that span the visible spectrum and at four t e m peratures from 20 to 80 ° C . SRM 1823 is issued as a unit consisting of t w o glass vials, with screw caps, each con taining 60 ml of liquid ($55/unit). For in formation and orders, write to the Of fice of Standard Reference Materials, Room B 3 1 1 , Chemistry Building, Na tional Bureau of Standards, Washington, D.C.20234
