Table
0
I.
Determination of Known Amounts of Phenaglycodol
Phenaglycodol, Mg. Diluent, hfg. Starch Lactose Taken Found 0 289.8 ’0 289.2 20.3 287.6 21.1 289.8 19.1 292.2 0 291.4 0 292,2 14.7 295,2 10.5 0 301 6 301.4 0 304.5 4.7 304.8 0 0 311.5 309.3 Including correction factor (see text).
attempt rras 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
70
Recovery“ 100,2 99.3 100 3 99.0 100 1 99 9 100 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
