burrell cathodic vacuum etcher fills the void in existing techniques and provides your laboratory with an almost UNIVERSAL TYPE ETCHANT A Burrell Cathodic V a c u u m Etcher permits t h e metallographer t o e x a m i n e with confidence grain size or o r i e n t a t i o n , primary and secondary phases, transformation p r o d u c t s , welds, clad materials, carbides, oxides, inclusions, refractories, c e r m e t s , and s o m e t i m e s , ceramics. Recent major advances in c a t h o d i c etching have been built into t h e Burrell Etcher, which has been simplified so personnel can get good results with brief instruction. A n d , Burrell's r e m o t e units assure t h e safe handling of radioactive or t o x i c materials. Burrell C a t h o d i c V a c u u m Etchings can be used in electron microscopy and are suitable for replication or direct scanning w i t h o u t special preparation. For more information c o n t a c t y o u r Burrell representative.
New Chemicals order blanks write to t h e Manager, Savannah River Operations Office, U.S. Atomic Energy Commission, P.O. Box A, Aiken, S.C. 2 9 8 0 1 Arsenic selenide, a new material for cell windown in infrared spectrophotometry, has excellent transmission from 0 . 8 16.7 microns and is almost completely flat to 12 microns. Arsenic selenide is insoluble in all organic solvents and in water and acids up to pH 1 1 , t h u s making it suitable for obtaining spectra where NaCI, KBr, and KCI are unusable. It h a s t h r e e times the h a r d n e s s of NaCI and twice t h a t of KRS-5, and is easily polished. Unimetric Universal Corp. 714-879-3777 505 A flame photometric grade of methane contains no impurities t h a t could cause undesirable flame color. The gas is specially prepared for use in auto-analytical instruments, such a s flame emission and atomic absorption. J. T. Baker Chemical Co. 201-859-2151
506 AM-ex-OL (4-chloro-2-phenylquinazoline) converts phenols to anilines in good yields. Even highly hindered phenols such a s phenolic steroids have been converted to t h e corresponding amines. Aldrich Chemical Co., Inc. 414-273-3850 507 Plasma Cortisol Klinikit contains all reagents and s t a n d a r d s necessary to perform 1 0 0 + determinations. A urinary catecholamine kit provides all reagents and s t a n d a r d s for a choice of 2 5 , 50, or 1 0 0 + t e s t s . Alpha Assoc. 215-9450140 508 Ultrex kits for checking the linearity and performance of spectrophotometers contain 100 ml of two concentrations of t h e standard (potassium dichromate in sulfuric acid or cobalt a m m o n i u m sulfate in sulfuric acid) and 100 ml of a sulfuric acid reference solution. One kit is for t h e ultraviolet (350 nm) and t h e other for the visible region (6 wavelengths in t h e 4 0 0 - 6 0 0 nm range). A certificate of analysis provides actual absorptivity values. J. T. Baker Chemical Co. 201-859-2151 509
B U R R E L L CORPORATION BURRELL
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SCIENTIFIC INSTRUMENTS AND LABORATORY SUPPLIES 2 2 2 3 FIFTH AVENUE, PITTSBURGH, PA. 1 5 2 1 9 CIRCLE 25 ON READER SERVICE CARD ANALYTICAL CHEMISTRY, VOL. 44, NO. 2, FEBRUARY 1972
Anion-exchange resins for the separation of polypeptides are especially useful for separating acidic polypeptides a n d / o r those with higher molecular weights. They are analytical-grade spherical resins selected for their separation properties, then narrowly sized. These resins are m a d e of polystyrene divinylbenzene, 2 % and 4 % crosslinked, with quaternary ammonium groups attached. $ 3 7 5 , 25 grams; $700, 5 0 grams. Durrum Chemical Corp. 415-321-6302 510