Since the color intensity depends upon
pH and temperature, the other oxidizing agent< do not interfere under the condition> used in these determinations and color is produced only with bromate or iodate. The above mechanism is supported by the fact that the absorption us. wavelength curve for the pink-colored solution obtained by reduction of 2,3,5-triilhenyl tetrazoliuiii chloride with hydrazine in acid medium and the color produced a i t h iodate or bromate were found to be identical with maximum
absorption a t 480 mp in both cases. The pink color produced with iodate or bromate can be extracted with benzene or nitrobenzene and hence the sensitivity of the method can be increased manifoldly. LITERATURE CITED
(1) “Encyclopedia
of Chemical Technology,” Yol. 7 , p. 585, Interscience Encyclopedia, New York, 1951. ( 2 ) Gotlib, A. L., J . A p p l . Chem. L-SSR (English T r a n s l . ) 11, 135 (1938). (3) Hashmi, M. H., Ahmad, H., Rashid,
-4.> Ayaz, A . A , , .INAL. CHEM.36, 2028 (1964). ( 4 ) Lambert, J . L., l b i d . , 23, 1247 (1951). ( 5 ) AlacDonald, J . C., Yoe, J. H.: A n a l . Chim. A c t a 28, 383 (1963). (6) Koller, C. R., “Chemistry of Organic Compounds,” 2nd ed., p. 638, R . B. Saunders, Philadelphia, 1957. ( 7 ) Vilborg, S. S.,Drozdov, V. A , , IzL.. Vysshikh Vchebn. Zaccdenii, Khim. a K h i m Tekhnol. 3, 75 (1960); C‘..-l. 54,
l6285f (1960). (8) 1-orobev, il. S., C-ch. Z a p . I-dmiirtsk. Gos. Ped. Inst. 11, 150 (1957); C.A. 54, 6386d (1960). RECEIVEDfor review June 17, 1964. iZccepted September 1, 1964.
Radio Release Determination of Vanadium in Water ARTHUR S. GILLESPIE, Jr., and HAROLD G. RICHTER Research Triangle Insfifufe, Box
490, Durham, N . C. 27702
,Vanadium in aqueous solution can b e determined quantitatively by the radio release method. The vanadate ion is assayed by acidifying the sample (pH by the addition of 200 mg. each of (ethylenedinitrilo) tetraacetic acid and either sodium fluoride or phosphate. For other colunins the coniplexing agents suppressed the iron(II1) activity by a factor of about 10. The need for a complexing agent in addition to EDTh is not fully understood; however, the combination does suppress iron(II1) in the range of pH = 3. Xo single component masking agent was found that would prevent or suppress silver oxidation by iron in the presence of 1,3diethyl-2-thiourea. From the present data it appears that the iron(II1) reaction with silver 1s slower than the vanadate reaction.
For moderate flow rates (1 to 3 nil,/ minute) through a column of coarse silver particles (small surface ar-a), the iron(II1) reaction rate is too slow to produce a measurable activity level although the vanadate reaction goes partially to completion. When columns containing finely divided silver particles (large area) are used, t,he vanadate reaction with silver goes to completion and the iron(II1) reaction activity is about of its stoichiometric value. It' would appear that an optimum flow rate exists for a particular column wherein the vanadate reaction is stoichiometric and the iron(II1) interference is a minimum. This has not been investigated in the present work. Dissolved oxygen does not interfere with this specific technique in spite of the fact that thermodynamically it should do so. hcids, except for powerful oxidizing acids such as HSOa, do not interfere. Nitrate ion does interfere at higher concentrations but not in the range to 10 p.p.m. LITERATURE CITED
( 1 ) Carroll, F. I., White, J. D., Wall, XI. E., J . Org. Chem. 28, 1236 (1963). ( 2 ) Ibid.,p. 1240. 13) GillesDie. A. S.. Jr.. Richter. H. G..
RECEIVED for review September 10, 1964. Accepted September 30, 1964. This work was carried out under Atomic Energy Commission, L3ivision of Isotopes Development, Contract No. AT-(40-1)-2513. Presented at the Pittsburgh Conference on hnalytical Chemistry and Applied Spectroscopy, IIarch 1964.
Titration of Aromatic SuIfinic Acids in Nonaqueous So Ivents DAVID
L. WETZEL'
and CLIFTON E. MELOAN
Department of Chemistry, Kansas State University, Manhattan, Kan.
b Acid-base titrations of sulfinic acids and mixtures of sulfinic and sulfonic acids with quaternary ammonium tiis trants in nonaqueous solvents possible. Titrants investigated were tetramethyl, tetraethyl, tetra-n-butyl, trimethyl benzyl, trimethylphenyl, and cetyldimethylethyl ammonium hydroxides. The following solvents were suitable for titrating milligram quantities of aromatic sulfinic acids, producing from 400- to 600-mv. changes: ethyl acetate, dimethyl sulfoxide, chlorobenzene, nitrobenzene, acetone, acetonitrile, diethyl ether, tetrahydrofuran, benzene-methanol, n-butyl alcohol, t-butyl alcohol, pyridine, dimethylformamide, and dimethyl aniline. In addition, the following sol2474
ANALYTICAL CHEMISTRY
vents produced at least 400-mv. changes when sulfinic-sulfonic acid mixtures were titrated with tetra-nbutyl ammonium hydroxide: benzenemethanol, t-butyl alcohol, tetrahydrofuran, dimethylformamide, and pyridine, In general, the relative standard deviation was within 70.2570 and the relative error within 70.4%.
S
ACIDS (R-SO2H) are notorious for their instability and the ease with which they undergo autoxidation. The corresponding sulfonic acid which is a final product of both the decomposition and autoxidation is a potential source of interference in the quantitative study of the acidic properties of sulfinic acids.
ULFINIC
There are a t present four areas of sulfinic acid analysis. These include the iron(1II) salt procedure (6, 7 ) , the nitrite titration (11, 13, f 4 ) , oxidation methods (1, 2, I O ) , and aqueous neutralization reactions. The need for the use of large samples, prior separations, temperature control, unstable titrants, or external indicators imposes limitations on these methods. The strength of sulfinic acids can generally be described as being greater than that of corresponding carboxylic acids and less than that of corresponding sulfonic acids. The relative acidity of the sulfinic acids has not been extensively used for analytical purposes, 1 Present address, Kansas State Teachers College, Emporia, Kan.
