ANALYTICAL CHEMISTRY
1354 llutual standard Plating Preliminary curve Prearcing Preburning Presparking Radiance Radiance, spectral Radiant energy Reference sample Reflectance Reflectivity Retained sample Reticulation Secondary standard sample Source
Spark Spectral slit width Spectr xxx analysis Spectrograph Spectrometer Spectrophotometer Spectrum Specular Speed Stimulus Thermosensitive detector Trace constituent Transmittance, internal Transmittance, spectral Transmittance. specular Wait
Am. SOC.Testing Materials, "Benzene and Toluene by Ultraviolet Spectrometry," ASThI Designation D 1017-51. Am. Soc. Testing llaterials, "1,a-Butadiene in Cq Hydrocarbon Mixtures by Ultraviolet Spectrophotometry," AST.\I Designation D 1096-50T. Am. Soc. Testing Materials, Committee D-2 on Petroleum Products and Lubricants, p. 744, 1951. Bayliss. S a t u r e , 167, 367 (1951). Brode, \T. R., J . Optical SOC.A n . , 39, 1022 (1949). Bunsen and Roscoe, Ann. Phys. Chem., 101, 235 (1857). Committee on Colorimetry, J . Optical SOC.Ani., 34, 183 (1944). Hodgman, C. D., "Handbook of Chemistry and Physics," Cleveland, C,hemical Rubber Publishing Co., all recent editions. Hughes, H. K., et al., "American Standard Letter Symbols for Physics," S e w York, American Standards Asdociation. 1948. Illuminating Engineering Society, Ken. York, "Illuminating Engineering Nonienclature and Photometric Standards," 1942. Iustitute of Radio Engineers, "Standards on Electronics," 1938. Institute of Radio Engineers, "Standards on Radio Receivers," 1988. Institute of Radio Engineers, "Standards on Transmitters and dntennas," 1938. Jones, L. A., J . Optical SOC.Am., 27,207 (1937). Jones and Condit, J . Optical SOC.Am., 38, 126 (1948). "Lange's Handbook of Chemistry," Sandusky, Ohio, Handbook Publishers, Inc., all recent editions. Lin Yutang, "The Wisdom of Confucius," p. 77, New York, Illustrated Modern Library, 1943. The translator explains that "ritual and music" does not render the full meaning of the original. "The philosophic meaning here is that if the basic moral and social order is not restored and the peoplo's proper habits of mind are not established, it is superficial folly to hope for the establishment of peace and order by relying on punishing the law breakers." Llelloii, hl. G., ".lnalytical .Ibsorption Spectroscopy." p. 189, X e w York, John TTiley 8; Sons, 1950. Rlellon, 11.G., J . Optical SOC.Avz.. 31, 648 (1941). Moon, P.. and Spencer, D. E., A m . .I. Ph~is..14, 285, 431 (1946). Ibid., 15, 84 (1947). Katl. Bur. Standards. Letter Circ. LC 857 (1947). Sewhall, S. 11..and Brennan, J. G., "Comparative List of Color Terms." \Tashington 4, D. C . , Inter-Society Color Council, 1949. Roller. Duane, Ani. J . P h y s . , 15, 175 (1947). Sper,?rographic Discussion Group, Glasgon-, Scotland, "Suggested Definitions of Terms Csed in Spectrographic Analysis," 1946. \Veld, L. I)., "Glossary of Physic.3." S e n - 1 - 0 1 k. 1lcGraw-Hill Book ['o., 1937. U.i?hro\\-,11. B.. Plant Phusid., 18, S o . 3 . 476 (1943).
SU\I.\lARY
In this paper a list of proposed terms and definitions in the field of applied spectroscopy has been presented together n-ith a group of general principles of nomenclature standardization which aid in the solution of controversial cases. T h e terms and definitions are published here for information only and are subject t o further revision. Comments on this report are solicited and should be addressed t o the Chairman of the Joint Comniittce on Sonienclature in Applied Spectroscopy, H. K. Hughes, Central Research Laboratorivs, Celanese Carp. of America, Summit, S . J. ACKhOW LEI)G>IE\T
.ll)out 60 persons have submitted their coninients on this and previous reports. T o thew and the many others n-hose reconimendations have come less dirertly, the committee wishes t o record its indebtedness. LITERATURE CITED
(1) h m . Inst. Elec. Engrs., Sew l-ork, "American Standard Defini-
tions of Electrical Terms." 1942. (2) .im. Inst. Elcc. Engrs., Electronics Committee. Infrared Appli-
cations Subcommittee. "Standard Definitions of Electrical Terms," ilSA Project C-42, 2nd rev., 1948. (3) Am. SOC.Testing Materials, "Analysis of 60 Octanc Sumbei. Iso-octane-Normal Heptane ASTM Knock Test Reference Fuel Blends by Infrared SIJcctiophotometry," AST11 Designation D 1095-SOT.
Volumetric Determination of Hypophosphate Ion THERALD RIOELLER
AND
GLADYS H. QUINTY
.Yoyes Chemical Laboratory, C'niuersity of Illinois, Urbana, I l l .
'
PHOSPHATE is niost conimonly dct,erniined b\- prwipi-
H '-;a(?ing
with e x e s 8 standard silver nit ratCsolution and measuring excess silver ion by titrating n.ith standard thiocyanate ~ o l u tion (6) or precipitating with chloride ( 2 ) . This procedure ip accurate b u t someIvhat tedious. .In even more t,ime-consuniinp procedure involves oxidizing t o orthophosphate with perninnganate and ultimately weighing as magnesium pyrophosphate ( 2 ) . Volumetric procedures have not proved generally acceptable. Permanganate oxidation ( 4 ) is reasonably rapid in hot solutions, b u t the results are apparently not completely accurate. Hydrolysing the hypophosphate t o phosphite and orthophosphat,eby evaporating n-ith hydrochloric acid and determining the phosphitc by the standard iodine procedure (-5)is accurate but somen-hat involved.
T h e success achieved in determining h>pophosphate in thoriumcontaining materials b3- oxidizing with cerium(IF') ( 3 ) prompted c\;tension of this procedure t o hypophosphates in general. Because this procedure depends upon the total reducing power of the -ample, it is not applicable t o mixtures containing hypophosphite 01 phosphite. As a method of standardizing hypophosphate solutions or of analyzing pure hypophosphates, however, i t is simple, rapid, and accurate. Extension of the procedure t o more involved caSes will require additional research. REAGENTS
Disodium dihydrogen hypophosphate 6-hydrate waE prepared and purified by the procedure of Leininger and Chulski (1). It was used in approximately 0.025 Jf solution. Tenth normal
V O L U M E 24, NO. 8, A U G U S T 1 9 5 2
1355
cn.ium(IT') aninionium nitrate solution, prepared froni the reagent quality salt, \vas standardized against pure arsenic(II1) oxide, using osmic acid as catalJ-st.
tion gave an average roncentrntion of 0.02595 M, with deviations of not more than 0.00005 .II. T h e concentration of this solution hased upon the assumption that the hypophosphate used ip a primary standard was 0.02595 JI. The concentration as determined b y the silver ion preciritation procedure ( 6 )was 0.0258 I l l . These results may be regarded as typical. It appears that accumulations of nitric acid u p to a t least joyo \yere Jvithout effect in the arsenite titrations. CorresIiondinglj.. no 1)l:ink corrections were found ne( ary, although blanks were run in all instances. The insolubilities of the cerium phosphate.* i ~ ~ n d the e r nitric acid deniands ],:ither high but do not affwt the :icc.uracy of the results.
PROCEDURE
A 5-ml. sample of approsiniatelj- 0.025 ,TI disodium dihydrogctn hypophosphate solution is treated with 10 ml. of approximately 0.1 S standard cerium(1V) ammonium nitrate solution and 5 nil. of nitric acid (specific gravity 1.12). T h e mixture is heated until the orange-brown precipitate which first forms redissolves. This may require boiling and t h e addition of more nitric acid. If t h r precipit,atedoes not disappear after 2 to 3 minutes of boiling, more. nitric acid is added in 2-ml. increments t o t h e boiling suspension until dissolution is complete. S o more than 10 t.o 12 nil. of nitric acid will be required in total. The, solution is cooled t o room trmperature, and sufficient nitric acid (10 to 20 ml. may h e r['quired) is added to dissolve any finelq- divided precipitate 01' ccxrium phosphates which maj. have formed during t h e cooling s ceriuni(1V) is titrated potentiometrically ite solution, using a trace of osmic acid as itity of hypophosphate is then calculatetl
I'!06----
+ 2Cp-+-- + 2I1,O
-+
2PO,---
LITERATURE CITED
' 1: Leininger, E., and ('hulski, T., J . I ~ L C'heni. . SOC., 71, (1949). 2 ) Probst. J.. 2. a r i o i ~ .t i . ! ( / l o e m . Chcm., 179, 155 (1929). ) Quinty. G . H., doctoral disswtation, University of Illinois. 1951. ) Rosenheim, and Pinsker, .J.. Z. anorg. Chcni., 64, 327 (1009). ) van S a m e . It. G., and Huff, IT. .J.. Am. J . Sci., 45, 91 (10181. R-olf, L.. and .Jimg, IT.,Z. ccriory. ii. aZlgr?n. Chem., 2 0 1 , :31; (19.31).
+ 2Ce-+' + i H -
HESlJLTS \ X I ) DISCUSSION
p:iratl>tilration? of
:i
g i w n sodium h!-por!hosi)hate sulu-
1 i b . i I ; I \ k:D
for revici\. Di
Determination of Organic Peroxides Dead Stop End Point Applied t o Iodometric Determination of Small Amounts of Organic Peroxidcs E. W. LBRAEI iJISON
AND HENRY
LISSCIIITZ
Syracuse Cnicersity, Syracuse, .V. Y . :wi I-rva?hed petroleum ether (30" t o 60" C.) follo\r.etl I,?. tre:itnient with activated charcoal and further rccrystallization (nirlting point 55.2' to 55.5" C.), Solutions of the pcnroxidr \?.ere n i ~ ~ l up t . in various pc.iuside-free hydrocarbon solvents.
pciuride (lcss than 0.01 m e , ) ivith a precision of a t least 1 % i n hytirocarlwn solutions, in t h e presence of highly colored d>-es. Although suitable iodomctric methods have been developed and evaluatcd (it), they are limited t o macrodetermin:itions by the low precision inherent in the visual end point based on presence of free iodine. since t h e starch end point cannot be used in semiaqueous media. Furthermore, the presence of colored matter or suspended solids which often accompanies perositie decomrjosi+ion in solution, renders the iodine visual end point practicall). uec~lcss. -\P a possible solution t,o this problem the "dead stop" end point indicator of Foiilk and Banden ( 2 )!vas investigated and found to be highly satisfactory fo? the titrat,ion of iodine in scmiaqueow media.
T h e procedure. for thc quantitative reduction of Tetralin hydroperoxide by iodide ion is similar t o t,he isopropyl alcohol method of Ft-agner, Smith, and Peters ( 4 ) . Thirty millilit,ers of anhydrous isopropyl alcohol and 2 ml. of glacial acetic acid are placed in t h e titration vessel. T h e solution is refluxed under a Soxhlet condenser for 1 minute and 0.2 gram of anhydrous sodium or potassium iodiLle is added slorvly. After further refluxing for 30 sec-onds, 1 to 2 ml. of the peroxide solution is added by mean!: of a calibrated pipet. T h e solution is then refluxed for 10 minutes, 5 ml. of water is added, and t h e solution is titrated with thiosulotherwise fate. T h e volume of titrant should not exceed 25 ml,; a n eniulsion may rcJsult.
APPARATUS
TITR.ATlON PROCEDURE
A flat-bottomed oylintlrical tube of about 100-ml. capscitj~, carrying a 15/50 standard-taper outer joint, is used for t h e titr:ition. .4n inner joint, fitting the titration vessel, is equipped Trith a mechanical st,irrer, tm-o platinum wire electrodes, a nitrogen buhhler t o provide an inert atmosphere, and a n opening foi, :i buret delivery tip. .I varial)lfi voltlge is supplied t o the platinum electrodes by a 100-ohm slick wire potentiometer, connected t o a 1.5-volt dry cell. I n series \vith t h e platinum electrodes is connected a 1tul)icon galvanorneter having a sensitivity of 0.0047 pa. per mni. and a resistmce of 80 ohms. I n t h e experiments reported here, 11 special, ca1il)ratetl 2bml. buret, graduated a t 0.05-ml. intervals, ~a.9 used. REAGEXTS AKD CHE>lICALS
Sodium thiosulfate solution (0.001290 .V) \vas prepared from C.P. materials, and standardized against C.P. potaspiurn iodate. T h e solution was saturated with nitrogen as a precaution against powihle ovvgen errors. T d r a l i n hvdroperovide was prepared by t h e method of Hock an(1 Susemihl (3). T h e crude product was recrystallized froni
PROCEDURE FOR PEROXIDE DECO3IPOSITION
.It the beginning of t h e titration both platinum electrotlcs R W depolarized so t h a t only a small voltage just sufficient to keep the g ilvanometer deflection on scale need be applied across the electrodes. As the titration proceeds the applied potential is slo\vl>. increased t o a maximum of about 10 mv. near the end point. .is the end point is approached the galvanometer deflection falls ripidly to a final, very small value. T h e last f e x drops of titrant should be added slowly, especially if emulsion develops, to allow for equililiration of the system. Moderate stirring anti continuous flushing of the vessel with nitrogen or cartion diosi:lr are maintained during the titration. EXPERIMENTAL RESULTS
T h e data of Table I illustrate t h e stoichiometric nature of the dead stop end point even when t h e titrant is extremely dilute. Under these conditions the visual end point is certainly of no value and t h e starch end point is not quantitative. T h e dead stop end points, on t h e other hand, are truly quantitat,ive, t,he average error being less than 0.5%. T h e original standardization
