REPORT FOR ANALYSTS
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BLENDERS I N ONE!
P-K Yoke model blender is ideal for small scale batch blending. Yoke arrangement fits standard 4 or 8 quart blender frame . . . permits two different blends at once . . . accommodates two 1 pint or two 1 quart or one 2 quart shell . . . or a combination of quarts, pints. Shells of heavy transparent Lucite or stainless steel can be removed in a jiffy. Yoke models are available from stock.
Changeover to single 4 or 8-quart shells for standard blending jobs is simple. Charging or discharging is easy through large access openings in the transparent Lucite or stainless steel shells. All p-k lab models utilize a gearhead motor with a chain and sprocket drive. Standard 4 and 8 quart lab model and extra shells are stocked for immediate shipment.
This is a p-k Twin Shell Intensifier model designed to produce completely uniform lab blends of materials difficult to mix. Shells are water and dust-tight, and can be clinically cleaned. Stainless, self-centering Intensifier bar (foreground) snaps into place, spins at high speed to break up lumps. Intensifier models are available from stock in 4 or 8 quart working capacities.
FREE To get the full story ask for our new catalog 14 The Patterson-Kelley Co. Inc., 2 3 1 0 H a n s o n Street, East Stroudsburg, P a .
PATTERSON-KELLEY Chemical and Process Division
Circle No. 30 A on Readers' Service Card, page 73 A 30 A
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ANALYTICAL CHEMISTRY
specks seen on t h e surface of the contents of t h e container. T h e same container might be examined b y another chemist in a less well illuminated area a n d might be passed. Recently a t e s t h a s been devised whereby a certain weight of fine chemical is p u t into solution a n d filtered through a s t a n d a r d 1-inch filter paper disk. S t a n d a r d s have been established which now permit t h e chemist t o m a k e a n objective s t a t e m e n t of t h e a m o u n t of extraneous material present in a specified weight of chemical. Since 1938 t h e Federal Food, D r u g and Cosmetic A c t [Section 501 (a) (2)] h a s carried t h e statement t h a t " a drug shall be deemed to be adulterated if it h a s been prepared, packed or held under unsanitary conditions whereby it m a y have been contaminated with filth, " Until recently t h e question of degree of contamination with extraneous materials h a s been purely subjective. Now, with t h e aid of t h e analytical research chemists who have examined m a n y hundreds of lots of chemicals a n d who have prepared reference standards from uniformly ground spectrographic carbon, we can assure ourselves t h a t t h e chemicals going into our pharmaceutical products are of a quality which cannot be deemed to be adulterated u n d e r this section of t h e D r u g Act.
Some Tests Superfluous In discussing various tools which have become available t o t h e analytical chemist during t h e past decade or two, we have purposely passed over lightly some tests found in various control specifications. These include determinations of moisture, ash, sulfate, chloride, a n d a n u m b e r of others. I t is suggested t h a t frequently some of these tests m a y be superfluous a n d could well be omitted, depending upon the final use t o which t h e chemical is put. Unless t h e moisture content h a s a specific bearing on either t h e identity or t h e p u r i t y determination, or has some effect upon t h e stability of t h e chemical during a storage period, t h e presence of a few t e n t h s per cent will usually offer nothing additional in t h e way of p u r i t y or identification. Likewise, one could consider t h e presence of chloride ion of no importance when t h e chemical is to be m a d e u p in physiological saline solution. Analytical specifications prepared b y the control unit should be practical a n d should reduce t o a minimum a n y u n i m p o r t a n t tests. I t would be well if all producers a n d consumers would read the specifications which t h e y have prepared for their various products a n d
give careful consideration t o t h e value of t h e m u l t i t u d e of u n i m p o r t a n t tests frequently placed in such specifications. Suggested Purity Criteria W h a t are t h e criteria of p u r i t y for fine chemicals a n d pharmaceuticals which are needed today? I n t h e a u t h o r ' s opinion these criteria m a y be broken down into four specific requirements: 1. T h e product must be identified beyond question. Tools for this m a y lie in t h e realm of infrared spectrophotometry, x-ray spectrometry, chromatography, crystallography, or other physical chemical measurements. 2. T h e product m u s t be free from products of similar composition. T h e tools available for this m a y be paper chromatography, gas phase chromatography, partition chromatography, or other partition techniques. 3. T h e product m u s t be p o t e n t (pure). Assay methods listed as available for this determination are ultraviolet spectrophotometry, spectroscopy, nonaqueous titration, a n d a number of other instrumental methods mentioned above. 4. T h e p r o d u c t m u s t b e p h a r m a c e u t i c a l ^ elegant. This means t h a t t h e product m u s t be free from extraneous color or dirt. T h e standardized extraneous material test mentioned above, which h a s been worked o u t in recent years, is applicable here. Let m e paraphrase a n advertisement which appeared in a recent edition of Chemical and Engineering News, " t h e spot on a paper strip—the peaks of a n infrared curve—the refractive index of a crystal—these are a few of t h e little things t h a t a d d to t h e final quality of a fine chemical." W h e n you have m e t t h e above criteria using precise instruments a n d equipment a n d truly analytical m e t h ods, then, a n d only then, do you have a product worthy of being labeled u n d e r your company n a m e as a fine chemical or a pharmaceutical. Literature Cited ( 1 ) Association of American Feed Control Officials, Inc., Official Publication, p. 32, 1956. (2) Brown, J. B., Marsh, M. M., ANAL. CHBM. 24, 1952(1952).
(3) Pharmacopeia of the United States of America, Wells and Lilly, Boston, Mass., 1820; 15th revision, Mack, Easton, Pa., 1955. (4) Schulz, E. P., Neuss, J. D., Division of Analytical Chemistry, 130th Meeting, ACS, Atlantic City, N . J., September 1956. (5) Strode, C. W., Stewart, F . N., Schott, H. O., Caldwell, J. E., Division of Analytical Chemisty, 130th Meeting, ACS, Atlantic City, N . J., September 1956.
