Spectrophotometric Determination of Submicrogram Amounts of Nickel in Human Blood MAXWELL L. CLUETT' and JOHN H. YOE Pratt Trace Analysis Laboratory, Department o f Chemistry, University of Virginiu, Charlottesville, Va.
b A method i s described for the determination of nickel in human blood. The sample i s wet-ashed with nitric acid and the mineral constituents are converted to chlorides with hydrochloric acid. Iron(ll1) and copper(l1) interfere and are separated b y ion exchange. Lead also interferes and is separated b y "adsorption" on calcium carbonate. Nickel is determined b y a spectrophotometric procedure based on the complex formed with diethyldithiocarbamate. The complex is extracted into isoamyl alcohol and the absorbance i s measured a t 325 mp in a 1 -cm. cell. The gram-atom absorptivity i s 37,000. The precision of the method i s indicated b y the average deviations of 0.005 and 0.009 p.p.m. of nickel obtained on synthetic blood ash and whole blood samples, respectively. Recoveries of added amounts of nickel were quantitative. The concentration of nickel in human blood was between 0.025 and 0.067 p.p.m. The method should easily be extended to other mammalian tissues and products.
T
mineral elements. in general. becanie closely identified n-ith enzyme and vitamin activity -1, the d i d covery that zinc is present in purified carbonic anhydrase and that cobalt is an essential part of ita am in B:?. Within this sphere of biochelnirni activity, manganese, cobalt, copper. 31iti zinc are noiv recognized :is essential; in the diet for normal hunian nutrition ( 3 ) . Although nickel general1~-ie c ~ ~ i i sidered unimportant as a trace element in tlie human body ( 6 ) : Bertr:ml :111d Sakamui,o (,$) concluded floni :i .-cries of experiments on synthetic. iiiitritioii that iikkel and cobalt p1:iy :i ilirec>t role in nutritional phenonienn. So values for the ( ~ ) n r e ~ i t r : i t i ~i'! tn nickel in human blood are rewrdeti i n the literature. Recently, Kovh and associates (10) reported hetn-een 0.01 and 0.085 p.p.m. of nickel in ~ii>rnial human pl:imia> the average vslue being 0.03. Recently, Monacelli, Tanalia, and Toe (Is)have reported on tlie RACL
Present address, Exprrimentd Station, E. I. d u Pont de S e m o i u s and Co , Inc., Kilmington 98, Del.
nickel cont,ent of human blood plasma, their average value being 0.04 p.p.ni., with a range of 0.01 t o 0.06. This paper describes a method that, can determine as little as 0.1 y of nickel in human blood. Quantitative recoveries of the nickel result from the ashing procedure and the procedure for the separation of iron(III), copper(II), and lead. Highly purified reagents and suitable precautions are necessary to prevent contamination. ;Iltliougli the method \vas tiereloped specifically for the determinntion of nickel in human blood, it should he applicable t o mamnialian tiwieq a n d products in general. The appliration of the n-et'-ashing procedure to R large number of organic materials of biological origin has been discussed fullJby X d d l e t o n and Stuckey ( 1 4 ) . Kraui and con-orkers (11-18. 16. 18) h a r e s h o w that the ion exchange procedure isolates nickel from a large number of possible interfering metallic ions, including manganese. iron, cobalt. copper. zinc, molybdenum, bismuth. mercury. and gold. Tin is separated a1w by the ion exchange procedure. and lead is separat'ed by adsorption 011 calcium carbonate. The unusually high sensitivity of the spect,rophotonietric procedure is particularly adrantageons where only small amounts of w i i p l e ~ are available for analysis. APPARATUS
Spectrophotometer. A Beckman quartz spectrophotometer. 3Iodel DT-. with calibratpd 1-cm. Corm nbsorption cells was employed. Separatory funnels. 30-ml. capacity. Stopcocks were lubricatpd with I h v Corning silicone grease. A 2 to 3 7 solution of hydrofluoric acid !vas w r y rfficiciit for remoying the film of silicon^ grease on the insidc n-alls of the f~iiinc~ls. Polyethyltw beakers. 30-1111. capacity (arailable a t Scitncc Housc. I ~ i c s . , Pittsburgh, Pa.). Evaporation C o w r . The apparatus s1iovc.n in Figure 1 n-as used for protecting the samples from air-liorne contamination. I t consists of a 250-n-ntt infrared bulb, A , the glass cowr, R. with a side arm, C, for introducing filtered air, and the crystallizing dish, D. Syringe Pipet. Polyethylene tubing 0.64 cm. in diameter was softened and drawn out to give a small tip. The
large end of the tube was attached to :I 1-nil. Tuberculin syringe. PolyethJ.1ene \vas preferred t o glass liecause it resists wetting. The ion exchange c*olumnw-asa siniplc buret type. Don-ex-1 resin was adticd as a slurry in triply distilled water to g i w a resin lied of aliout 28 cm. X 0.20 sq. c111. The calcium carbonate column n-a< constructed from a standard 1-nini. bore. straight stopcock. Specpure c d ciuiii rarbonate powder (Johnsoil. Matthey and Co., Ltd., London, England) 11-as added as a slurry in tripl!. distillc>d water to give a bed of about 8 cni. x 0.20 sq. em. Air pressure x i s applied to obtain a flow through thc column.
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tFigure 1 .
fI 76"
-4
Evaporation cover
Spectrographic :inalyscs were made nit11 an Applied Rcsrarch Laborator>'I-iiiet,er grating ::pec trograph, nioc lified as describ(Jd by T h i m and Yoc (21). The electrodes were cut from a spccial spectrographic grade of graphitr rod (Sational Carbon Co., Inc.). Samples were added to the electrodes by t h r solution technique. Anode excitation with a 9-ampere direct current a r t w i s employed. Second-order spectral lines were photographed 011 Kodak S. A. S o . 2 film in the ~ a lcrigth v ~range' of 4700 t o 6900 A. CEAGENTS
Triply Distilled Water. Laboratory-distilled watei, was rrdistilled tnice in borosilicate glass stills in series. The final distillate \\as conVOL. 2 9 , NO. 9, SEPTEMBER 1957
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densed in a quartz tube and collected in a polyethylene bottle. Hydrochloric Acid. Hydrogen chloride gas (hlatheson Co., Inc.) was bubbled through concentrated sulfuric acid, filtered through borosilicate glass wool, and dissolved in triply distilled water in a polyethylene container (cooled in a n ice-water bath) t o give a concentrated acid. T h e acid was standardized a n d 8.0, 0.5, and 0.005M solutions were prepared b y appropriate dilutions with triply distilled ivater. Acid t h u s produced n a s spectrographically free of nickel. Standard Nickel Solution. A solution containing 0.98 mg. of nickel per ml. was prepared by dissolving 0.250 gram of Matthey nickel sponge (Johnson, hlatthey and Co., Ltd.) in 10 ml. of strong hydrochloric acid, filtering, and diluting to 250 ml. n i t h triply distilled water. The solution 11 as standardized gravimetrically by the dimethylglyoxime procedure and a solution containing 0.98 y of nickel per ml. was prepared by dilution. Citric Acid Solution. A 20% (w./v.) solution of reagent grade citric acid was prepared in triply distilled water. T h e solution \\as filtered. Diethyldithiocarbamate Solution. A 0.2% solution of sodium diethyldithiocarbamate trihydrate (Eastman Kodak Co., Rochester, X. Y.) mas prepared in triply distilled water. This solution, stored in polyethylene, was stable for a t least 2 months. Ammonium Hydroxide. Reagent grade ammonium hydroxide u-as distilled into triply distilled water until t h e concentration was 15X. Nitric Acid. Reagent grade acid was distilled. T h e acid produced was spectrographically free of nickel. Sodium Heparin, solid salt (USP, Organon, Inc., Orange, S . J.). This material was spectrographically free of nickel. Solutions of Diverse Ions. Except for a few cases where reagent grade chemicals were used, dilute hydrochloric acid solutions of t h e metal ions were prepared from special spectrographic grade chemicals (Johnson, Matthey and Co., Ltd.). Ion Exchange Resin. Dow Chemical Co., Dowex-l-X8 resin in t h e chloride form, 50 t o 100 mesh, was used.
EXPERIMENTAL
Sampling. T h e procedure for collecting t h e blood samples was developed during a n earlier investigation carried out in this laboratory (10). Thirty-milliliter hypodermic syringes, containing the sodium heparin, were used and the samples transferred to small polyethylene bottles. When duplicate analyses were desired, aliquots were measured in appropriately sized graduated cylinders within 1 hour after the sample was taken. Immediately before the sample was divided, it was shaken to ensure uniform mixing of the cells and plasma. 1266
ANALYTICAL CHEMISTRY
Ashing the Sample. The net-ashing procedure is based on a method developed by Middleton and Stuckey (14).. ils these investigators pointed out, incandescent spots occur when the flask is placed on the hot plate after the addition of nitric acid to the hard black residue. These “hot spots” might cause the loss of some of the more volatile metals, such as zinc and lead, but there was no indication of loss of nickel. Dry-ashing a t 450’ C. gave results in good agreement with wet-ashing (Table 111).
Table I.
Interference of Diverse Ions Amount, AbsorbIon Y ance
K+ Na Ca+-
20,000 1-0.003 20,000 +0.092 500 -0.005 RIg + + 400 -0.004 Fe+++ 4.000 +O ,030” Al++10 0 000 Pb+’ 10 f O 090 Sr++ 10 -0 003 10 -0 002 Li cu++ 10 +O 070 Zn+10 +o 002 10 +o 002 Cr Mn-+ 10 -0 003 10 +O 003 Sn+’ P + + + + ’(as PO,---) 10 -0 005 B + + +(as B407--) 10 +0.006 Si+’++ (as Sios--) 300 +O 002 a Citrate apparently does not completely mask reaction of iron(II1) at high con+
from a 7 to 8.M hydrochloric acid solution (11, 18). Metals which do not form negatively charged compleves with chloride ions-for example, the alkalies, alkaline earths, aluminum, and chromium-accompany the nickel in the separation. Elution studies shon et1 that a large portion of the lead in :I sample also appears in the emuent containing the nickel. Attempts to mask the reaction of lead with diethyldithiocarbamate by adding excess acetate ( 7 ) or rhodizonate (8)nere unsuccessful. d spectrophotometric correction of the interference is not poqsible because the lead complex qhon s no absorption maximum above 320 mp. Lead is separated by its selectile adsorption on calcium carbonate from neutral or alkaline solution. Thi, method was suggested by the relative solubilities of lead, calcium, and nickel carbonates.
+
centration.
Procedure. Transfer t h e blood sample (usually 10 ml.) t o a 125-ml. Erlenmeyer flask, and add 5 ml. of concentrated nitric acid and 0.5 ml. of hydrogen peroxide solution (307,, reagent grade). Place on a steam bath overnight. Remove t o a cool hot plate and bring t h e temperature u p t o 330’ C. Leave t h e flask uncovered on t h e hot plate until there is no visible reaction (about 15 minutes). Allow the flask to cool, add 0.5 ml. of concentrated nitric acid, and cover with a watch glass, being careful to leave a small opening through which gases can escape. Return the flask to the hot plate and continue to heat for 15 minutes after the residue has become dry. Allow the flask to cool and repeat the operation as often as necessary, until a white residue is left. Add 0.5 ml. each of 8.011.1 hydrochloric acid and hydrogen peroxide solution, cover with a watch glass, and continue as above, repeating this operation three times or until no nitrogen oxide fumes are visible. Add 5 ml. of 8.OM hydrochloric acid and heat on a steam bath for 15 minutes to dissolve the residue. Separation of Interfering Ions. Iron, copper, and lead, a t t h e concentrations in which they occur in normal human blood, interfere in t h e spectrophotometric method for nickel (Table I). Iron and copper are separated on Dowex-1 anion exchange resin
0
2 4 6 8 VOLUME OF EFFLUENT, ML.
Figure 2. Integral elution curves for nickel through ion exchange column Procedure. Transfer t h e strong hydrochloric acid solution of the blood ash t o a polyethylene beaker, which is placed in t h e apparatus shown in Figure 1. Evaporate the sample to about 1 ml. or until precipitation just begins. Acidify t h e ion exchange column (prewashed with 60 ml. of O . O O j N hydrochloric acid) with 14 ml. of 8.OM hydrochloric acid. Collect the last 5 ml. in a borosilicate glass beaker and use this for the blank determination. Transfer the concentrated sample with a syringe pipet to the column, using three 03-ml. rinses with 8.0111 acid to complete the transfer. After each addition to the column, allow the level of the liquid to reach the glass wool plug a t the top of the column. Continue the elution with 8.0-11 acid a t a flow rate of 0.25 ml. per minute, discarding the “free volunie” and collecting
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SAMPLE ( 5 Y N i ) vs. BLA,NK W
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0 m m
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BLANK vs. PURE SOLVENT
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15 20 TIME, M I N .
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Figure 4. Effect of settling-out time on absorbance of isoamyl alcohol extract
ash solution. A sample of a “synthetic blood-ash” solution. containing approximately the amounts of the various ions listed in Table I, was employed WAVE LENGTH,MM to determine this elution procedure. Aliquots of the efFigure 3. Spectral curves of nickel diethylfluent were analyzed spectrodithiocarbamate extracted in various solvents graphically. The 0.005Y hydrochloric acid cannot be used I.lewiireinent s z s. blanks exclusively, because in this I. Iqoanigl alcohol low acidity the iron band at 11. Chloroform 111. Bromobenzene the top of the resin bed hyIV. Carbon tetr:tchloridp drolyzes and complete elution is difficult to obtain. Samples containing 1 to 3 y the next 3 nil. in a borosilicate glass of nickel and f0 y of lead shoned an beaker. Evaporate the blank and average recovery of 98 + 5% through sample to 0.05 to 0.10 ml. and then the calcium carbonate column. No lead dilute to 1 ml. or less with triply distilled was detected spectrographically in the n-ater to dissolve the salt residue. Add effluent n h e n 20 ml. of a 20-p.p.m. lead 3 drops of citric acid solution and a small solution was passed through the column. piece of red litmus paper, and neutralize Iieutralization of the concentrated hy adding concentrated ammonium sample from the ion exchange treatment hydroxide dropivisr. (It is very imin the presence of citric acid prevents portant to add equal amounts of citric acid to the blank and sample, to obt,ain a precipitate (probably of calcium precise conipensnt’ion for any trace of silicate) from forming in the beaker. copper in the reagent. The small However, immediately following the piece ol red litmus paper does not transfer to the calcium carbonate colintroduce any contamination.) Transumn, a precipitate will form, apparfer the blank and saniple each to a ently secded b y the borosilicate glass calcium carboilate coluniii, using three wool plug a t the top of the column. ivitli triply distilled \rater. A spectrographic analysis shon-ed no Aftcr carli addition to the colunin, allow nickel in the precipitate. X large the level of the liquid to reach the glass w o l plug a t the top of the column. excess of citric acid should be avoided Continue the elution (under pressure) because it will dissolve some of the \\-ith 2 nil. of triply distilled ivater a t a calcium carbonate from the lead-reflow rate olO.15 nil. per minut,e, collectmoving column. ing the cfflucnt iri a scparatory funnel. Spectrophotometric Determination of Nickel. T h e obvious advantages Integral elution curves for nickel of using t h e smallest possible volume through the ion exchange colunin are of blood for analysis led t o a search shown in Figure 2 . The first 2 ml. of t h e literature for t h e most sensitive of the effluent is the free volume, organic colorimetric reagent reported which is dependent upon the dimensions for nickel. Sodium diethyldithiocarof the column, the size of the resin parbamate ( 2 , 17) has a sensitivity a t ticles, etc., and must be determined for least t\\-o and one-half times greater cnch column used. Samples of known than the next best reagents, including amounts of nickel (I to 5 y) showed a n the vic-dioximes (9), dithizone (19), xverage recovery of 100 =t4% through and potassium dithio-oxalate ( 2 2 ) . The the ion exchange column. diethyldithiocarbamate method has the Twenty milliliters of 0.5M hydrochloric acid and 60 ml. of 0.005M acid advantage of simple reaction conditions were used to elute the ions adsorbed and a final extraction of the nickel on the Dowes-1 resin from the blood complex which is favorable for obtain-
ing maximum concentration of the absorbing species. Procedure. T o t h e blank and sample, each in a separatory funnel, pipet 0.50 ml. of t h e citric acid solution a n d add a small piece of red litmus paper. Seutralize with concentrated ammonium hydroxide and add dropnise a n amount in excess t o give a pH of about 9.5. Pipet 1.0 ml. of diethyldithiocarbamate reagent, dilute t o 10 ml. with triply distilled water and mix thoroughly. Pipet 3.0 ml. of isoamyl alcohol and extract the nickel complex by shaking vigorouslg for 2 minutes. Allow the layers to separate for 20 minutes. Remove the aqueous phase and pour the extract through the top of the funnel into a 1em. absorption cell. Because of an insufficient volume to fill the cell, place it so that its base is in line with the bottom of the “windon” of the cell holder. d small polyethylene plug may be used to support the cell if necessary. Measure the absorbance of the sample isoamyl alcohol extract a t 325 mp, using the blank extract as it reference I n isoamyl alcohol the nickel complex is stable for a t least 2 days. Effect of Extracting Solvents. T h e curves in Figure 3 show t h a t isoamyl alcohol is better t h a n a n y of t h e solvents tested for t h e extraction of t h e nickel complex. Isoamyl alcohol separates as t h e upper layer from t h e aqueous phase. KO difficulty n-as evperienced in transferring t h e isoamyl alcohol upper phase into t h e absorption cell through the top of t h e separatory funnel. Any droplets of water accompanying the transfer quickly settle to the bottom of the cell and do not interfere 11-ith the measurement. The curves in Figure 4 show that a settling-out time of at least 15 minutes must be allowed to obtain mavimum absorption. Absorption of Blank. T h e blank absorption curve us. pure solvent is shown as curve 1 in Figure 5 , Homever, t h e true spectral curve of t h e blank, which is obtained b y subtracting curve 2 from curve I , exhibits a steadily increasing absorbance down VOL. 29, NO. 9, SEPTEMBER 1957
1267
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BLANK vs. PURE SOLVENT
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SAMPLE ( 5 7 N i l vs. BLANK I 2 3 4 CONCENTRATION, PER CENT ( W / V ) Figure 6.
Effect of salt concentration
sample isoamyl alcohol ey0.020' t o 1.40 p.p.m. ( A = 0.880)tract. The increasing abLe., 0.10 to 4.2 y of nickel per 3 ml. 320 360 400 of wlvent The gram-atom ahqorpsorbance of the blank eyWAVE LENGTH, MJJ tract shown in Figure 6 is due to the interfering trace Figure 5. Absorption of blank metal ions in the citric acid Table 11. Analysis of Synthetic Blood solution. Because nearly all 1. Blank determination I ' S . piire solvent Ash Solution" 2. Extract of alkaline t,riply distilled lvater I S . pure the electrolyte content of the 10-ml. aliquots used) solvent a m p le a c c o m p a n i e s t h e SI Si 3. Water v s . pure solvcnt nickel through the ashing Saniplr Itlded, Found, I:II 0 1 , s o 1' P.11 P.P.11. P P 11 and separation procedures, 0 101 +0.003 1 0.098 the salt concentration in the 2 0.098 0.106 +0.008 to wave lengths belo17 325 mp. The spectrophotometric procedure is one half 0.059 c0.010 1 0.049 apparent maximum a t 333 mp which the maximum allowable. Ten milliliters 0.041 -0.008 4 0.049 is obtained when the blank is measured of Ivhole blood contains approximately 0.051 +0.002 %in.049 against the pure solvent, is caused by .-IT, (lev. =0.005 0.1 gram of inorganic electrolyte ( 1 ) . the presence of nat'er which dissolves 10-nil. aliquot contained approxiBeer's L a w and Sensitivity. Beer's matelj- the amounts of various ions listed in in the alcohol phase. The absorption law is adhered t o over t h e concenTahlr I. of water us. pure isoamyl alcohol is tration range 0.033 12.p.m. (9 = shon-n as curve 3. Extraction of the reagents with diethyldithiocarbamate. carbon tetrachloride, and,!or isoamyl alcohol n-as inefficienthlowring the abTable 111. Analysis of Human Blood sorption of t h r blank at 325 nip, Compcnsation by the blank is maintained Sample Sample Volume, Ashing SI accurately by pipetting the reagenh. Dpsignation 111. Procedure P.P.11. A 4 ~ 7 ~ ~P.P a g c11. ~, Effect of pH. Extraction of t h e IT-hole hlood nirkcl complex \Tas found to hc in.4 10 \T-et 0 048 dependent of the pH of the aqueous 0 0;71 0 053 phase. Hon-el-er, the absolbance of 5 Di,y 0 060 3325 the blank extract from acid medium 0.067 CI 270" was considerably greater than from 326 9 K et 0 026 0 026 alkaline medium (>pH 9). The high Drv 0 021 0 02j absorbance of the blank extract from 0 02T 0 024 acid solution is due, a t least in part, ,328 to the extractability of the diethyldithiocarbamic acid ( 5 ) . The presence of int'erfering ions in the solution also results in positive errors, because cit10 Wet 0 035 336 0 0x3 0 034 rate does not complex metals such as 0 037 Drr 0 063 iron(II1) in acid solution. Hydrogen 0 01; 0 040 ion concentrations between pH 2 and 3337 10 K et 0 087 10 were obtained by varying the 0.062 0 036 amount of ammonium hydroxide added. 3340 10 wet 0 025 Effect of Salt Concentration. 0 032 0 029 Various salt concentrations were obB 10 n-et 0 03-1 tained by adding increasing volumes 0 026 0 018 of cit'ric acid solution to a number of . i v . 0 041 nickel samples. T h e pH in each case Plasma \vas adjusted t o 9.5 =k 0.2 with 122 10 n-pt 0 012' ammonium hydroside. Figure 6 .iverage deviation, f 0 . 0 0 9 p.p.ni. shows bhat a salt concentration (cal* 0.196 p.p.m. of nickel added to this sample. culated as diammonium hydrogen Duplicate aliquot analyzed spectrographically by llonacelli ( 1 5 ) . Si concentral ion citrate) greater than 2.4% causes a found was 0.015 p.p.m. decrease in the absorbance of the I
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0
1268
ANALYTICAL CHEMISTRY
tivity i> approximately 37,000 a t 325
w. Precision. D a t a were obtained on 0.5-7 amounts of nickel, about the normal cQntent of 10 ml. of whole blood. The standard deviation on 10 replicate samples was 0.02 7 or i%.
Interference from Diverse Ions. Analyses were carried out o n individual synthetic solutions containing, except in t h e case of zinc. a t least t h e amount of each ion normally expected in 10 ml. of whole blood. Values for the metals present in n-hole blood gii-en by dlbritton ( 1 ) . together with \-slues made available hj- the Pratt Trace Analysis Laboratory, ivere used in tlie preparation of the solutions. An aLqohance greater than ‘0.010 1‘s. a l h i i k vias arbitrarily chosen to indicate interference. As shonn in Table I. iron, copper, and lead interfere. The concaentration of zinc in whole h h d is a t least ten times greater than i q iiidicat’ed in the table. €Ion-ever. zinc will not interfere because it is separated in the ion exchange procedure ( 1 1 ) . Other ions, not listed in Table I. which might be present in human blood do not interfere. Thiq was established by analyzing spectrographicall!- tlie isoamyl alc~~!io! ex-
tracts obtained from the analysis of several whole blood samples. RESULTS
The results of the analysis of a synthetic blood-ash solution and of human blood samples are given in Tables I1 and 111. Sickel was determined in the synthetic samples with an average deviation of 0.005 p.p.m. The average deviation calculated from the blood data in Table I11 is 0.009 p.p.m. The concentration of nickel determined in human whole blood ranged from 0.025 to 0.067 p.p.m.; the average concentration in blood from eight patients !vas 0.041 p.p.m. I n one sample of plasma the nickel concentration \vas 0.012 p.p.m. LITERATURE CITED
( 1 ) Albritton, E. C., “Standard 1-alues in Blood,“ p. 117, W. B. 8:iiindrw
Co., Philadelphia, 1952. ( 2 .\lrsander, 0 . It., Godar, 1,;. lI,, I,inde, S . J., ISD. EXG. CtrEx.. AS.^,. ED. 18, 206 (1946). ( 3 I Bell, G. H., Davidson, J. S., Scarborough, H., “Textbook of Physiology and Biochemist1 D. 80. E. & S. Livineston. Ltd.. 1
Edinburgh, 1953.
-
( 4 ) Beitrand, G , Nakamwa, H , Rtili soc chzn,. btol 16, 1366 (1934) ( 5 ) Bode, H , 2 anal L‘hent 142, 414
(1954).
END
(6) Everett, hl. R., “hledical Biochemistry,” 2nd ed., p. 608, Paul B. Hoeber, Inc., New York, 1944. ( 7 ) Feigl, F., “Chemistry of Specific, Selective and Sensitive Reactions,” p. 89, Academic Press, New York, 1949. (8) Ibid., p. 174. ( 9 ) Ferguson, It. C., Banks, C. L-., A S A L . CHEM. 23, 1486 (1951). (10) Koch, H. J . , Jr., Smith, E. R., Shimp, 1.F., Conner, J., Cancer 9, 499 (1956). (11) Kraus, K. A , , lIoore, G. E., J . Ani. Chem. SOC. 75. I460 11953). (12) Kraus, K. -$., kelsonj F., I b i d . , 76, 981 i19-54) 984 (1954). r a n S ,K. A , , Selson, F., iroorp, Krans, lIoorp, (13) ~ G.. E., I b i d . , 77,3972 (1955). G (14) lIiddleton, G., Sttickey, R . E., Analyst 79, 138 (1954). 1 15 i lIonacelli. It.. Tanaka. H.. Tiocl. J. H., ’Clin,’ (‘him. Acta ’1, 577 (1956). (16) l l o o r e , G. E., Kraus, K. A , , J . A m . Chem. SOC.72,5792 (1950). 117 1 Siistinen. R.. Tamminen. V.. Suotrieri \----I.
ScJlson, F., I i t , a d , K.’ A , , J . -3 m. (‘hrm. SOC. 76,5916 (1954). Shprwood, It. ll.,Chapman, F F. K., ,Jr., .4sar,. CHEJI.27, 88 (19: (1955). Thirrs, R. E., Killiiims, J. F., Toe, J. H.. Ibid.. 27. 1725 (1955). Thiers.’R. E.: Y&. J. HI..SOC.d ~ o l . Spe&oscopy B d i . 5 , 8 11951). ( 2 2 ) I-oP, ,J. H., Wirsing, F. H., J . A m . Clfelfl S O C . 54, 1866 (1932). .
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RECEIVEDfor rrvien l r n r c h 11, 19.57. .\ccrptrd Julv 10, 1957.
OF SYMPOSIUM
Efficient Use of the IBM File of ASTM Powder X-Ray Diffraction Data THOMAS
E. BEUKELMAN
Jackson Laboratory, E. 1. du Pont de Nemours & Co., Inc., Wilmingfon, Del.
b The use of the IBM file of powder x-ray diffraction data compiled and published b y the Joint Committee on Chemical Analysis b y X-Ray Diffraction Methods of the American Society for Testing Materials is discussed. A sorting procedure based upon the statistical distribution of holes in the IBM punched card i s described for the qualitative analysis of multicomponent samples. The method i s also applicable to use of IBM files of infrared and ultraviolet absorption data.
T
powder x-ray diffraction (data publibhed by the Joint Coniniittee on Chemical Analysis by S-R:i>. Diffraction Methods of the ;Inierican Society for Testing llnterial. have long &ice proved their usefulness for HE
the identification of unknon n niaterials by their x-ray diffraction patterns. However, the I R M punched card file of these data as originally developed by the Wyandotte Chemicals Corp. ( 2 ) has not been aq n idely used. This may be partially the reiult of the more elaborate equipment needed for the handling of punched cards. but milalso be caused t)? an incomplete appreciation of their urefulnew in x - r q diff ractioii anall-sis. The file of 3 X 5 inch cards of powder diffraction data, familiarly knov n as the A S T l I file, or even the Numerical Indexes ( 1 ) furniqhed in book form to the users of the A S T l I file is normally adequate for the identification of singleconiponent samples. The greateqt utility of the I R l I file i. in the analysis of multicomponent samples, where each of
the three qtrongest cliffraction inasinia may arise from different conipounds. I n this case the usual practice of match. ing by searching for a single roinpound containing all three strongest diff riwtion riiaxima will proliubly fail. Another difficulty is the rhance coinc.itlence of minor tiiffraction imtziino of tn-o o r more components. \vhic*h leads to :i niasiniuni irliose intensit!. may lie out of proportion to tlie diffraction Ixrtterns of any of the component.. I n bhis case, too, the extensive cross-indexing possible n-ith punchetl i.:ircl techniques may lie used t o full ad\-antage. The method described here is not a rapid o r shortcut method. I t is a method for searching all of the availahle data in a comprehensive imnner and should be used only after niore rapid methods have failed. VOL. 29, NO. 9, SEPTEMBER 1957
1269
