1286
ANALYTICAL CHEMISTRY
Extraction with Sulfuric Acid and Hydrochloric Acid. The procrdure dewribed above was used, except that the internals t a n d u d solution was not added to the oil.
and acid layers is easier. It is somewhat faster than total sulfated ashing, and is more reliable because of smaller corrections for blanks.
SFECTROGR.AFHIC A S L Y S I S OF R E S I D U E S
ACKNOWLEDG.MEVT
.ill inorganic residues were dissolved in hot hydrochloric acid, treated with 0.200 ml. of the cobalt nitrate solution. and concentrated t o about 0.2 ml. These concentrates were evaporated on flat chamfered electrodes t h a t had previous1)- been sealed with white oil. T h e inorganic deposits were then subjected to spectrographic excitation under the previously described conditions. T o prepare calibration standards. the proper amounts of the reference solutions w r e aliquoted to give a series of standards representing 0.02 to 5.0 p.p,m. of copper, iron, lead, nickel. and vanadium, in terms of a 100-gram ssmple of oil. T o each standard were added 0.500 ml. of the cobalt nitrate internal-standard solution and the same amount of concentrated hydrochloric acid t h a t \\-as used to dissolve the inorganic residues. T h e solutions were then treated in the same manner as the hydrochloric acid solutions of the ashed residues. .Ifter the photographic plates were processed, the spectral lines for cobalt, copper. iron, lead, nickel, and vanadium included in Table I1 were photometered. Korking curves were prepared as described in the procedure.
The assistance of J. \T. D i s with t h e spectrographic analyse? is gratefully acknodedged.
R E S C L T S A Y D DISCUSSIOY
Spectrographic results are presented in Table i-, I h c h value is t h e avei age of two or thIee individual analyses.
LITERATURE CITED
(1) dnderson, J. \I7.$ and Hughes, H. K., - 1 s . k ~ . C m x . 23, I : E Y (1951). (2) Barney, J. E..and Kiniball, W.A , , Ibid., 24, 1548 (1952). (3) Calkins, L. E.,and White, 11. A I , , Proc. L4m. Petroieum I n s t . , 111, 26, 80 (1946). (4) Carlson, 11.T.. and G u m , E. L., ANAL.C m x , 22, 1 119 (1950). (5) Gamble, L. IT., and Kling, C . E., S p e c t r o c i i h . I d a , 4, 439 (1952). (6) Garner, F. H.. Green, S. .J.. Harper, F. D.. and Peg&., 11, E., J . Inst. PetroZeum. 39, 2778 (1953). ( 7 ) Gassman. -1.G.. arid O’Seill, 11‘. R., - 1 ~ sC~ HE .I I . . 21, 417 (1949). (8) Gottsch, F.,and Grodinan, B.. Am. SOC.Tesli’iig M a t ~ ~ i a l s , Proc., 40, 1206 (1940). (9) Groennings, S... h . t r . . ‘?HEM., 25, 938 (1953). (10) Ham, A. .J.. S o a r , .J.. and Reynolds, J. G., A ? f a l y s / , 77, iG6 (1952). (11) Harvey, C . E.,“.I3Iethod of Semiquantitative Spectrographic .\nalysis,” -4pplied Research Laboratories, Glendale. Calif.,
1951. ( I 2 ) Harvey, C . E.. “Spe~~t~ocherniral Procedures,” .lpplied Research
Table V.
a b
Spectrographic Analysis of Gas-Oil Residues
(Parts per million) Method of Separation Cu Fe Pb Ashing 0.20 Simple 0.030 0 93 0 18 Partial sulfated 0 048 0 55 0.38 Totalsulfated 0 051 0.92 Extraction a 0 33 Iodine HBr-CHjCOOH 0.055 0.93 0.38 HI-CHaCOOH 0.016 0 48 0.24 HzSOd-HC1 0.050 0.92 0.38 Blank too high to permit accurate measurement. Rlaximiiin ralues.
Si
v
0.023 0.022 0.023
0 18 0.17 0 18
0.021 O.OISa 0.022
0.16 0.17 0.16
0.19
If total sulfated ashing is selected as t h e baqis of ro’iipaiiron, four observations applv t o the other procedures. Onlv acid extraction or extractions with hydrobromic and acetic acids recover t h e five metals quantitatively. Extraction v ith hydriodic and acetic acids recovers most of the vanadium and lesqer a-nounts of the other metals. Extraction n i t h iodine iq rompletel\ unsatisfactory. Because neither simple ashing nor partial sulfated aching recovers lead quantitatively, the loss seems to occur during combustion rather than ignition. These observations are valid only for the gas oil studied. Some nickel, vanadium, and perhaps iron may be lost during combustion of other petroleum fractions. Loss of metals b y entrainment or by incomplete separation in acid extraction may depend on t h e state of combination of t h e metals in t h e oil. t h e boiling range of the oil, and t h e concentration of t h e metals themselves. Simple ashing should not be indiscriminately w e d in determining trace metals in petroleum fractions. I t should only b e used in comparing similar samples where speed is of primary importance. If a series of like samples is t o be analvzed, the amounts of t h e various metals lost by simple ashing may b e determined once b y comparison Kith a more accurate procedure and corrected for. Of t h e two methods giving quantitative results, extraction n ith sulfuric acid and hydrochloric acid is better than extraction Ivith hydrobromic acid and acetic acid. .is a routme method it is less hazardous and faster, and physical separation of the oil
Laboratories. Glendale. Calif.. 1961. (13) Hopps, G. L..and Rerk, .I..I., .~N.AL. C H E U . . 24, 1050 (1952). (14) Karchmer, J. H.. Proc. A m . Petroleicm I n s t . . 111.2 9 M , 72 (1949). (15) Karchmer, J. H.. andGunn. E. L., A - h - .CtH~E.Y . . 24,17% (1952). (16) Key. C.if-,, and Hoggan. G. D., I b i d . . 25, 1673 (19.53). (17) Lykken, L..Fitzsiininons, K. R.. Tibhetts, S. d..and Wyld. G . , Petroleirm Re.fifi,zer.24, 405 (1945). (18) IIcClintock, T.L.,Ph.D. thesis. Reneselaer Polytechnic Institute. Trov. S . 1.. 1950. (19) Nilner, 0.0.. Glass, J . 11.. Kirchner, J. P., and Yuri(,k.A . S . , . h . k L . C H E Y . , 24, 1723 (1952). (20) Murray, 31. .J.. and Plaoge. H. .I., Proc. A m . P e t r o l m m Inst., 111, 2 9 M , 84 (1949). (21) Overburger. C. C., and Danisshevsky. I.. U. S. Office of S a v a l Research 3Iirrocards. U23123, 1952. ( 2 2 ) Padiassotti. J. P., and Porsche, F. W., .$NAL. C H E M . , 23, 1820 (1951). (23) Rittershausen, E. P.. and DeGray, R . J., 1x0. ESG. C H E Y . , . ~ X A L .ED.. 14, SO6 (1942). (24) Sacks, IT,, Canadinri J . Technol., 29, 492 (1961). I n d . E ~ i y Chem., . 44, 1159 (1952). (25) Skinner, D..I,, (26)‘Treibs.-1.. A 4 ~ m509, , 103; 510. 42 (1934): 517, li2; 520, 144 (1935). (27) Treihs, -4.. ATzgeic. Chem., 49,682 (1936). (28) IT’oodle. R. A , , and Chandler, JT, B.. Iiad. Eng. C‘hen~..44, 2591 (1952). (29) Wrightson, F. I I . , .Is.ir..CHE’\I., 21, 1543 (1949). RECEIVED f o r review .Janriarp 3, 1955, Accepted April 13, 1955. G. P. Haight, Jr., was engaged as consultant a t Standard Oil Co. (Indiana) Laboratories; summer, 1953.
Determination of l o w Alkalinity or Acidity in Water-Correction I n the article, “Determination of Low Alkalinity or Acidity in Water’’ [Larsen, T. E,, and Henley, Laurel, . 4 s a ~ .CHEM., 27, 881 (1955)], the acknodedgment in the first sentence of the second paragraph is incorrect. T h e data reported in Figure 2 were obtained on surplus portions of samples collected in connection with a subcontract with t,he Cloud Physics Project of the University of Chicago, a research project sponsored by the Geophysics Research Directorate of the Air Force Cambridge Research Center, ;iir Research and Development Command, under Contract dF10(601)-618. The authors wish to espress their thanks for the privilege of using these samples.
T. E. LARSES LAURELHESLEY
