Quantities of Organic Compounds in ture of salts, have been replaced with a Biological Systems. Critical Evaluation of fusion in a platinum crucible with potasthe Use of Ion Exchangers. N. D. eium persulfate. This fusion is suggested CHEROKISAND STAMOSELEFTHERIOU,as a general method for mineralizing orBrooklyn College, Brooklyn, S. Y. ganic samples. The oxidation to hexavalent chromium is performed by the well known hypobromite oxidation. After deThe use of ion exchangers for the fracstroying excess oxidant, the Cr+6 is detionation of carboxylic acids, carbonyl termined spectrophotometrically under opcompounds, and amino acids has been timum conditions utilizing ‘Is-diphenyl studied. Using columns of varying carbazide.” The conditions affecting the lengths and diameters and several kinds of determination, such as time, pH, etc., w x e resins, it was determined that even with discussed. the most efficient columns there was an unavoidable loss of material due to holdup in the column. The relation between the Paper Chromatography in Steroid loss of material and the length of the resin Analysis. L. M. REISEKE,Department of column was discussed. The holdup varies Biochemistry, The Upjohn Co., Kalamawith the length of the column and the zoo, Mich. nature of the functional groups present in the compounds passed through it. Paper chromatography has been a p plied to the identification and quantitation Under optimum conditions, the loss is 1 mg. of carboxylic acid and carbonyl comof steroids obtained from microbiological pounds; for amino acids the loss is about and chemical transformations. il dear indication of the probable structure is ob50 and 75 y . The methods for determining per cent adsorbed and eluted were distained by the following criteria: ultracussed and the possibility of using “chasviolet absorption, chemical tests, and ers” for the amount held in the column. mobility (as compared to various known steroids) in a variety of solvent systems of both the Bush and Zaffaroni types. A Titrations in Anhydrous Media, a quantitative procedure using light abVersatile Tool in the Microchemical sorption a t 224 and 242 m l has been deLaboratory. J. F. ALICISO,Squibb Instiveloped for progesterone and lla-hytute, Yew Brunsmick, N. J. droxyprogesterone. This procedure eliminates the necessity for running blanks and Much information is gained by the use steroid standards with each determination. of this simple and rapid technique as is This method has also been used with evidenced by its application to the analyses methyltestosterone and 11a-hydrosymethof various substances such as amino acids, yltestosterone. alkaloids, amines, salts, sulfa drugs, vitamins, purines, heterocyclics, antibiotics, etc. Accurate analyses on a few milligrams Fractionation of Fluoresceins and Sulfonphthaleins and Determination of Their of material can be performed rapidly and inexpensively within the space limitations Purity by Circular Paper Chromatography. of the average microchemical laboratory. ADOLPH FKERST .4SD N. D. CHEROSIS, Examples of the utility of the method in Brooklyn College, Brooklyn, N. Y . elucidating the nature of some unknown The application of the circular paper compounds were given. chromatographic technique to the fractionation of seven substituted fluoresceins Microdetermination of Reducing Sugars and eight sulfonphthaleins commonly emby Tetrazolium Salts. Application to ployed as acid-base indicators was reMicrodetermination of Reducing Sugars ported. Of the 85 solvent systems tried as in Blood. SICHOLM D. CAERCINIS .~SD developer?, three were chosen which gave ~ I I C H Bc. E LZYMARIS, Brooklyn College, satisfactory fractionatiom: a mixture of Isaac Albert Research Institute, Brooklyn, 3q sodium chloride and 5% pheno!; a K . T. 15yc solution of aqueous ammonium sulfate; and 1% aqueous sodium carbonate. For the microdetermination of reducing This method of fractionation gave rapid sugars by means of tetrazolium salts, the and reliable information as to the purity of proper selection of a suitable tetrazolium acid-bnse indicators, particularly the brosalt and 3 modification of existing methods mosulfonphthaleins, T\ hose piirit! cannot make it possible to obtain reliable results be determined readily either bv melting a t concentrations of a few micrograms. points or by determination of halogm conThe tetrazolium salt selected is p-.lnisyl tent. Blue [ 2,2-diphenyl-5,5-p-anisyl-3,3(3,s-
dimethoxy-4,4-biphenylene)-ditetrazoliuni chloride]. The factors which influence the precision and accuracy of the method, such as temperature, pH, and concentration of the salt, were critically evaluated. The method may be applied to the determination of reducing sugars in blood. Results from 65 randomly selected samples of protein-free filtrates give close agreement with the results obtained, using the Ne1 son-Somogyi method. The determination can be made on a sample of 0.05 to 0.1 ml. of blood.
Microsynthesis with Diazomethane. ROBERTROPER4 N D T. S.Ma, Kew York University and Brooklyn College, New York, K.Y.
Diszomethane has found. a variety of important uses in organic chemistry. Hoi-iever, the highly poisonous and explosive nature of the gas has limited its suitability in many cases. Working with diazomethane on a micro scale minimizes these hazards. The advantages of diazomethane as a reagent in micropreparations were pointed out by von I’echman in Microdetermination of Chromium in 1895. Many of its reactions run very Collagen Sutures. ERIK R. HOPFMANN smoothly and in good yields. Thew is a AND MARYG. COMFORT, Ethicon, Inc., minimum of by-product formation, and Somerville, N. J. excess reagent may be removed with ease. A microgerierator has been constructed A method has been developed for the defor the evolution of diazomethane from termination of chromium in “catgut” potassium hydroxide and nitrosomethyl sutures. A complete analysis may be run urea, allowing millimolar qnantities of pure in less than 15 minutes. Older methods diazomethane to he prepared. This of mineralization utilizing acid mixtures, method has been applied to the microincluding perchloric acid, high temperapreparation (50 to 100 mg.) of methyl esture muffle furnaces, and oxidizing mixters of carboxylic acids in good yield. If
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ether solutions of diazomethane are used directly, without distillation through the apparatus, the yields are very poor. Many other uses for this technique were described. Preliminary Examination of Inorganic Substances by Heating in Hydrogen. A. A. BESEDETTI-PICHLER, Queens College, AND HERBERT SCHNEIDER, Brooklyn College, Brooklyn, K .Y. The examination of substances in the “dry way” preceding dissolution and systematic analysis has been for the most part disregarded when working on semimicro and micro scales. It seems that the preliminary examination may often greatly simplify the task of the microanalyst, if a suitable procedure is used, which gives information concerning cations and anions present. Blowpipe analysis is often a shortcut to the identification of compounds of heavy metals. A possibly even more informative procedure has been found, which is based upon the heating of substances 0x1 a current of air, followed by reduction in n current of hydrogen. Some examples were discussed, which show the advantages ot this approach. New Method of Prenarative Electrophoresis. hl. BIER, Forhham Universitj , New York, N. T. Methods available at present are limited to rather small volume capacity. This limitation is overcome in the recently developed continuous free-boundary flov electrophoresis which, for the first time, provides the means for large scale fractionation, concentration, or purification of proteins and other charged colloids. The present laboratory model of the apparatus is compact and simple. The solution to be fractionated is exposed to a strong, direct current electric field while passing through u system of three parallel semipermeable membranes in appropriate arrangement. The separation of the components takes place in a free flowing vertical column, taking advantage of the laminar f l o ~of the liquid. The sample is separated into t n o fractions, one containing the proteins at, or near, the isoelectric point, and the other containing all the electrically charged components. The method was applied to the single step preparation of human gamma-globulin from plasma, utilizing f l o ~ rates up to 4 ml. per minute. Parallel arrangement of a number of cells may increase this yield to industrially important quantities. The process can also be applied for the concentration of protein solutions, the extent of the concentration being limited mainly by the Rolubility of the protein.
Corrections T h e author index for Volume 28 lists a paper by Zenchelsky and Showell, “Thermostated Xicrocell Adapter for Perkin-Elmer Infrared Spectrophotonieters.” as apptwing on page 2035. This paper was published on page 167 of the January 1967 issue. On page 329 of t h e March issue of name of the fifth author should have been spelled Meloche. ~ ~ ? ; A L P T I C A LCHEMISTRY, the
