You need EDTA in your lab for
FASTER ANALYTICAL RESULTS, IMPROVED SYNTHESES and SEPARATIONS
Y o u c a n benefit in m a n y ways w h e n y o u use Ethylenediamine Tetraacetic Acid, 'Baker Analyzed' Reagent, and its disodium salt ( d i h y d r a t e ) . E D T A has the ability to form stable and soluble complexes with most di- and trivalent metallic ions. This chelating p r o p e r t y permits the use of E D T A for the selective precipitation and separation of s o m e cations including those of the rare earths. In t h e purification of organic and inorganic chemicals, E D T A has been employed for its "masking a c t i o n " on trace metals often present as c o n t a m i n a n t s . F u r t h e r , E D T A c a n be used for the determination of m a n y metallic ions employ ing various analytical techniques including s p e c t r o p h o t o m etry and titrimetry. F o r m a n y applications the disodium salt ( d i h y d r a t e ) of E D T A is preferred because of its solubil ity, stability, and favorable p H . M a n y of the benefits of E D T A are described below in the specific applications. Also included are references to t h e b r o a d line of associated chemicals and indicators which are being offered by Baker. DESCRIPTION Ethylenediamine Tetraacetic Acid ( E D T A ) and Disodium Ethylenediamine Tetraacetate, Dihydrate, are offered in the reagent grade as a crystalline powder and are controlled to an assay speci fication of greater than 99 per cent. Critical impurities—heavy metals and iron—are held at the low levels indicated by the actual lot analyses provided on the label. Both reagents are stable and may be used directly for the convenient preparation of solutions. APPLICATIONS • In Colorimetry—EDTA serves in colorimetric analysis both as a masking agent permitting greater specificity and as a component of color systems.
• In Selective Separations—EDTA often functions as a complexing or masking agent in analytical and preparative separations to reduce interferences, secure greater specificity, or to permit more selective reactions and separations. The use of EDTA to gain added specificity in sulfide and potassium precipitations with thioacetamide and sodium tetraphenylboron, respectively, is of special interest. • In Polarography—EDTA serves as a masking agent and complexing agent in various polarographic procedures. • In Titrimetry—EDTA as its disodium salt serves as titrant in the EDTA titration by which over 40 elements may now be easily and rapidly determined either directly or indirefctly. This titration employs many 'Baker Analyzed' reagents for buffering, pHadjustment, masking and demasking, preliminary separation, etc. Especially noteworthy are the metal indicators introduced or offered by J. T. Baker in the reagent grade with controlled sensitivity. These include Eriochrome Black Τ (CI 203), murexide, PAN, Pyrocatechol Violet, Zincon, and calcon (CI 202). Other 'Baker Analyzed' reagents finding use in end point indica tors for the EDTA titration include thiourea, ammonium and potassium thiocyanates, benzidine, dithizone, and potassium iodide. These metal indicators, of course, have other important applications especially as chromogenic agents for the detection and colorimetric analysis of various metals. Original articles and continuing reviews on E D T A are appearing in CHEMIST-ANALYST, the quarterly professional journal published by J. T. Baker. Product data sheets on E D T A and associated reagents and indicators are also available. Leaders in the field of analytical chemistry have described E D T A and sodium tetraphenylboron as the two most significant ad vances in laboratory reagents in the last decade. J. T. Baker has taken the initiative in informing the chemist about these advances through a strong publication program and in providing these rea gents produced to appropriate standards.
J. T. Baker Chemical Co. REAGENT
INDUSTRIAL
Phillipsburg, N e w Jersey For further information, circle "2nd Cover" on Readers' Service Card, page 73 A
