OVENS WHY USE KJELDAHL?

With Blue M it does mean selection. And with Blue M, choice also means highest quality. We offer you both. Is anything less worth your time? Where the...
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Where The Choice Is Yours OVER 1000 MODELS

OVENS

Blue M has anticipated your every oven need with a choice of over 1000 models . .. ranging from a $200 lab oven on up to a $20,000 fully automated inert gas chamber with microprocessing control. Mechanical and gravity . . . sizes to 96 cu. ft. . . . temperatures to +704°C. Batch . . . Life-Test . . . Utility . . . Burn-In . . . Drawer . . . High-Powered . . Vacuum . . . Drying — even FRICTION-AIRE® the patented electric chambers with no heating elements. Most have Blue M control systems for superior performance - plus such other standard features as welded stainless interiors, elapsed time meters, overtemperature protection. It's easily America's finest, most complete line. Choice. With Blue M it does mean selection. And with Blue M, choice also means highest quality. We offer you both. Is anything less worth your time? Where the choice is yours: Blue M Electric Company; Corporate Headquarters; Blue Island, Illinois 60406; Telephone: (312) 385-9000.

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WHY USE KJELDAHL?

The microprocessor controlled Model 707 provides accurate and rapid nitrogen/protein analysis! • Uses proven chemiluminescent detection principle • Programmed temperature • 5 to 120 samples per hour • Up t o 1 g sample size • 1 nanogram sensitivity • Up to 9 0 % protein See us at booths 204 and 206 at the 1980 Pittsburgh Conference in Atlantic City.

Typical Applications nitrogen sample content type 13 4 4 % (84% as protein} cattle feed 60 ppm (1500 ppm as slip) polyethylene 3000 ppm coal 3 65% (22 8% as protein) aifaifa

sample weight 100 mg 180 mg 300 mg 100 mg

relative standard deviation 1 05% 1 29% 0 47% 0 61%

ANTEK INSTRUMENTS, INC. 6005 North Freeway Houston, Texas 77076 Tel: (713)691-2265 TWX: 910-881-1792

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818 A • ANALYTICAL CHEMISTRY, VOL. 52, NO. 7, JUNE 1980

and in many instances, reaction equations and structural formulas associated with these methods are provided. The book is divided into six chapters. In chapter 1, the author skillfully treats a wide range of topics concerned with the analysis of free glycerol in a variety of materials. An excellent survey of analytical methods for the analysis of combined glycerol in naturally occurring and synthetic materials is presented in chapters 2, 3, and 4. Chapter 2 encompasses various analytical methods that focus on the chemical and spectral characteristics of residual hydroxyl groups; whereas chapter 3 deals with methods involving the sequential treatment of samples, i.e., chemical or thermal degradation to release bound glycerol, and chemical or instrumental analysis to determine the freed glycerol. Chapter 4 contains a compilation of methods for the analysis of glycerol-containing compounds where the emphasis is on the activity of the total molecule as opposed to a specific parameter of glycerol. Methods cited in chapter 5 are primarily concerned with specification compliance testing of refined or chemically pure glycerol. The inclusion of references is not consistent with the thoroughness exhibited in previous chapters; nevertheless, the overall organization and presentation of material is good. The sixth and final chapter by A. A. Newman is a brief, but enlightening, discourse on significant methods for the enzymatic determination of glycerol. Since this review is intended as an exhaustive survey of the available literature, the reader is exposed to many antiquated and obsolete methods, notably some dealing with wet chemical methods, paper chromatography, and classical column chromatography. On the positive side, the outdated technology is strongly supplemented by a wealth of information on modern analytical techniques such as IR, HPLC, GC, and GC-MS. Understandably, due to the multiplicity of closely related subjects, some chapters overlap; and techniques such as GC, etherfication, esterification, and IR appear in different segments of the text. Some of the references dealing with these topics are duplicated. An outstanding feature of this book is the effective use of tables for the compilation of pertinent details of analytical procedures categorized according to their analytical schemes. For example, Table 1.2 is concerned with "Gas Chromatography of Glycerol Esters," and lists sample types, acylation conditions, chromatographic