diameter, equipped at one end with a side a r m for t h e admission of steam a n d at t h e other end with a copperjacketed condenser. Steam generator connected t o t h e nickel t u b e b y Tygon or heavy-walled rubber tubing. Resistance-type tube-furnace capable of obtaining 1400' C. The finely divided powder or machine chip sample is weighed into a small nickel or platinum boat. The boat is inserted into the tube and steam is passed over the sample for 1*/2hours a t a furnace temperature of 1100' C. The steam flow is regulated to produce 1 to 3 ml. of distillate per minute. The distillate is collected in a Teflon beaker containing 20 ml. of distilled water and sufficient base to keep the solution alkaline. The boron in the distillate may be analyzcd by a n y of the conventional methods for the element, the level determining the mode of analysis. The distillates obtained from the materials analyzed t o date have been completely free of interfering elements. EXPERIMENTAL WORK
I n most of the work reported here, a
temperature of 1100" C. has been used for the pyrohydrolytic process. Several runs made a t 1300" C. indicate that boron can be quantitatively separated in 30 minutes, but the life of the nickel tube is shortened considerably a t this higher temperature. Alloys such as Stellites and Inconel, which are more stable a t the higher proposed temperatures of operation (1300" C.), are being investigated as possible tube materials. The use of platinum or platinum-clad base metal is also being considered. The rate a t which the steam is passed over the sample (1 t o 3 ml. per minute) has little effect upon the rate of separation of boron. The effectiveness of separation of boron by pyrohydrolysis is illustrated b y the data in Table I. The method appears to be almost universally applicable t o the separation of boron from various matrices, including even very refractory materials. The dissolution of such materials, frequently by lengthy fusion methods, is not necessary if the
pyrohydrolysis method of boron separation is employed. A complete study of the parameters and mechanism of this xllethod of boron separation is being performed. A detailed paper, including all findings, mill be published later. During the course of this work, the separation of boric oxide from glasses by pyrohydrolysis was reported by Williams and coworkers (1). LITERATURE CITED
( 1 ) Williams, J. P., Campbell, D. E., Magliocca, T. S , ANAL. CHEX 31,
1560 (1959).
V. R. WIEDERKEHR G . W. GOWARD Bettis Atomic Power Laboratory Westinghouse Electric Corp. Pittsburgh, Pa. RECEIVED for review September 23, 1959. Accepted October 5, 1959. Work s u p ported by the U. S. Atomic Energy Commission under contract AT-11-1-GEN-14 with the Westinghouse Electric Corp., Bettis Atomic Power Laboratory.
Determination of a Substituted Glycol by EIe ct roIytic Oxid a ti o n SIR: Examination of the literature shows no electrolytic oxidation of glycols as a n analytical technique. Allen has only three references to the electrolytic cleavage of glycols of any kind ( I ) . The compound phenaglycodol, which has the chemical name 2-p-chlorophenyl3-methy1-2,3-butanediol, has been found to be split by electrolytic oxidation to give a product having an ultraviolet absorption spectrum with a potential use for quantitative analytical applications. The procedure is being published now because of the novel nature of the reaction. It is unlikely that any further publication on this subject will come from these laboratories. The physiological properties of phenaglycodol have been discussed ( 2 ) . The reaction taking place during electrolysis niay presumably be written as follows: OH OH Cq-$L-CHs
0
p-chloroacetophenone and of the oxidation product, indicating that the oxidation product has no other interfering ultraviolet absorption except perhaps for a slight absorption due to acetone at short wave lengths. Phenaglycodol itself shows only weak absorption to the p-chlorophenyl group. APPARATUS
WA/E .rVd-?
V
Figure 1. Ultraviolet absorption curves -Authentic pchloroacetophenone (0.0161 mg./ml.) in water Oxidation product from typical run
---
+
AH3LIIJ
P
CHs C-CHa
+ Ha0
No attempt was made to study the kinetics of the reaction or t o determine the amount of acetone formed. Figure 1 shows the correspondence of the ultraviolet absorption spectrum of known
The electrolysis cell used was a 300m1.-high side beaker closed by a rubber stopper through which passed a condenser, the anode, and the cathode compartment. The anode was a commerci:i11y available platinum gauze of the type used as a cathode in electrolytic copper determinations. 'lhc cathode coinpartmerit was simply a piece of 12-niiii. glass tubing with a tight plug of filter paper as a diaphragm a t the bottom. A spiral of copper n.ire served as the cathode and 31" sulfuric acid served as the catholyte. The direct current p o w r supply was a simple variable transformer and selenium rectifier conibinntion of the type used to power HO model trains. The combination used \vas manufactured by Scintilla Rail arid Power Works, 324 Lafayette St., Ncm York, N. Y. According to the manufacturer, the unit has a continuous rating of 1 ampere a t 12 volts. This unit provides only pulsating direct current and no VOL. 31,
NO. 12,
DECEMBER 1959
2103
Table
I.
Determination of Known Amounts of Phenaglycodol
Phenaglycodol, Mg. Taken Found 289.2 289.8 291.4 295,2 301.4 304.8 309.3 0
289.8 287.6 292.2 292,2 301 6 304.5 311.5
Diluent, hfg. Starch Lactose ’0 21.1
0 14.7 10.5 4.7 0
70
Recovery“
0 20.3 19.1 0 0 0 0
100,2 99.3 100 3 99.0 100 1 99 9 100 8
Including correction factor (see text).
attempt was made to smooth the current flow. p-Chloroacetophenone used as a standard 11-as a n Eastman product and was purified by recrystallization byfreezing. A Cary recording spectrophotometer, hlodel 11, was used for the ultraviolet absorption memurements. PROCEDURE
One hundred milliliters of a solution of phenaglycodol containing about 1 mg. per ml. in glacial acetic acid was placed in the electrolysis apparatus. To this was added 100 ml. of 2N sulfuric acid. The apparatus was then closed and a current of 0.10 ampere passed for 1 hour while the solution n-as stirred with a magnetic stirrer. The voltage between anode and cathode varied between 3.8
and 4.2 volts for different runs. depentling on such variables as misalignment of the anodeandvxiationsinacid strength. At the end of the run, the apparatus n-as taken apart, the anode rinsed with water, and the anolyte plus rinsings made up to 250 ml. with Kater. A 5-nil. aliquot of this n-as then diluted to 100 ml. with water for determination by ultraviolet absorption. The reference cell contained a solution of acetic acid and sulfuric acid a t the same dilution as in the sample. Under the operating conditions described, the solution remains essentially colorless. In an attempt to reduce the time required by increasing the current, it was found that the solution became yellow. At the same time, the ultraviolet curve showed additional absorpt’ion a t wave lengths shorter than the
p-chloroacetophenone peak. This was probably due to some second reaction setting in with the increase in potential and, as this seemed undesirable, the current and voltage were set so that this did not occur. Table I shows the results of experiments to determine the recovery of knon-n amounts of phenaglycodol. Some of the determinations mere made in the presence of lactose and starch as representatives of the binders and fillers found in capsules and tablets. The actual yield of p-chloroacetophenone was 96.5%, based on the equation given above, and a factor n.as used in the calculations to allon for this, so that the table shows essentially 1 0 0 ~ o recovery on all amounts taken. The standard deviation based on these results is & 0.64%. LITERATURE CITED
(1) Allen, hI. J., “Or anic Electrode Processes.” , D.. 118. Rein%old. Kew York. 1958. (2) Slater, I. H., Jones, G. T., Young, IT’, K., Proc. SOC.Exptl. Biol. and M e d . 93, 528 (1956).
Analytical Department HARRY -4.ROSE Eli Lilly &- Co. Indianapolis, Ind. RECEIVEDfor review July 20, 1959. -4ccepted October 8, 1959.
Chromatographic Detection of Meprobamate SIR: Because there is wide interest in detecting small amounts of psychotropic agents in biological tissues or fluids, this report on the detection of meprobamate is offered as a n improved modification. The method designed b y Rydon and Smith (1) for the detection of peptides and similar compounds on paper chromatograms has been used in staining meprobamate and compounds containing the carbaniate group (2). The spots appearing after development with the starch-potassium iodide reagent soon fade and require immediate mnrking or recording by photography. I n the chromatographic determination of meprobamate and its carbamate metabolites the following modification which yields more stable spot development is suggested. The chromatogram is run and airdried to remove the solvent. The paper is then placed in a chlorine gas atmosphere for 15 minutes. The paper is removed and immediately sprayed with 2 104
ANALYTICAL CHEMISTRY
a n aqueous solution of fluorescein sodium, l to 10,000. When viewed under ultraviolet light the meprobamate spots appear dark purple against a fluorescent background. Spots of 3 to 5 y can be seen clearly. The spots are completely stable for 2 months or longer. A slight amount of fading has been observed over a 6-month period following development. LITERATURE CITED
(1) Rydon, H. N., Smith, P. W. G., Nature 169, 922 (1952). (2) Walkenstein, S. S., Knebel, C. AI.,
Macmullen, J. A., Seifter, J., J. Pharmacol. & Exptl. Therap. 123, 254 (1958). JOHN L. EWIERSON Toll S. MIYA
Department of Pharmacology Purdue University Lafayette, Ind. WORKsupported by the National Institute of Mental Health, Grant hf-2405.
Solvent Effects on the Electrooxidation of Iodide lonCorrection I n the communication on “Solvent Effects on the Electro-oxidation of Iodide Ion” [ANAL. CHEX 31, 955 (1959)] the first two sentences in the third paragraph should read: Chronopotentiograms for the electrooxidation of iodide ion a t a platinum foil electrode in aqueous 0.1M sodium perchlorate indicated a single ta-o-electron step for the formation of iodine, as expected ( I , 5 ) . The E l l , and 0.059/n values were 0.51 volt us. S.C.E. and 0.033, respectively.
R. T. IWAMOTO
