Industrial and Engineering Chemistry : analytical edition, Vol. 10, No. 11

IN D U S T R IA L

a n d E N G I N E E R I N G

C H E M I S T R Y

Vol. 30, Consecutive No. 43

H a r r iso n E . I lo w e , E d ito r

AS*

o

ANALYTICAL EDITION

20,100 Copies of This Issue Printed

Novem ber 15, 1938

Vol. 10, No. 11

S p e c t r o g r a p h i c A n a l y s i s o p B i o l o g i c a l M a t e r i a l . .

...Jacob Cholak and Robert V. Story 619

D e t e r m i n a t i o n ' o f R h e n i u m . E s t i m a t i o n i n P y r o l u -

s i t e . . . . Loren C. Hurd and Clarence P. Iliskey 623

M e a s u r e m e n t ’ o f R e f r a c t i v e I n d i c e s o f R e s i n s a n d P l a s t i c s ...C. D. West 627

E f f e c t o f I o n s o n M o h r M e t h o d f o r C h l o r i d e D e t e r ­ m i n a t i o n ... R. T. Sheen and H. L. Kahler 628

Ni t r o m e t i i a n e. Po t e n t i a l Ha z a r d si n Us e . . . .

. D. S. McKittrick, R. J. Irvine, and I. Bergsteinsson 630

I r o n D e t e r m i n a t i o n i n P r e s e n c e o f T i t a n i u m U s i n g Z i n c R e d u c t i o n . E m i l Truog and R . W. Pearson 631

D e t e r m i n a t i o n o f G e r m a n i u m i n M i n e r a l s a n d S o l u ­

t i o n s . . . W. C. Aitkenhead and A. R. Middleton 633

St a n d a r d i z e d Me t h o d f o r t h e De t e r m i n a t i o n o f Vi t a m i n Bi ...

G. C. Supplee and R. C. Bender with the technical assistance of L. C. Babcock 636

G l a s s - E n c l o s e d M a g n e t i c S t i r r e r . . J. H. Simons 638

Ni t r i c Ac i d Pa r t i n g o f Si l v e r As s a y Be a d s Co n t a i n­ i n g Pl a t i n u m Me t a l s a n d Go l d ...

...J. Seath and F. E. Beamish 639

R a p i d M e t h o d f o r G o l d i n C y a n i d e P l a t i n g S o l u ­ t i o n s ...Joseph B. Kushner 641

P - Hy d r o x y p h e n y l a r s o n i c Ac i d a s Re a g e n t f o r Ti t a n i u m a n d Zi r c o n i u m...

... C. T. Simpson and G. C. Chandlee 642

Fi l l i n g Cl o s e d- En d Me r c u r y Ma n o m e t e r s...

...Jesse Werner 645 Ab s o r p t i o n Ef f i c i e n c y o f Sp i r a l Ga s- Li f t Wa s h

Bo t t l e... B. B . C o rso n 646

I m p r o v e d V a c u u m R e g u l a t o r . . . Clayton W. Ferry 647 Sm a l l Lo w- Te m p e r a t u r e Re c t i f y i n g Co l u m n ". . . .

J. H . Simons 648 Mo d e r n La b o r a t o r i e s:

H o o k e r E l e c t r o c h e m i c a l C o m p a n y R e s e a r c h O f f i c e B u i l d i n g ...G . F . Rugar 649 M i c r o c h e m i s t r y :

Su l f a t e Ti t r a t i o n. Us e o f Te t r a h y d r o x y q u i n o n e i n Se m i m i c r o m e t h o d...

... W. A. Peabody and R. S. Fisher 651 De t e r m i n a t i o n o f Sm a l l Am o u n t s o f Po t a s s i u m

D . S . Brown, R. R. Robinson, and G. M . Browning 652

M i c r o s c o p i c I d e n t i f i c a t i o n o f S o m e I m p o r t a n t S u b s t i t u t e d N a p h t h a l e n e s u l f o n i c A c i d s . . . .

. . . . Willet F . Whitmore and Arthur I . Gebhart 654 A n g u l a r C o n s t a n t s o f M i c r o c r y s t a l l i n e P r o f i l e s

a n d S i l h o u e t t e s i n C o n c l u s i v e I d e n t i f i c a t i o n o f S u b s t a n c e s ... A . C . Shead 662 Ac c u r a t e Mi c r o m a n o m e t e r...

... C . C . Winding and F. H . Rhodes 665 Ca t a l y t i c Co l o r Re a c t i o nf o r Tu n g s t e n...

... E. B. Sandell 667 B u r e t T o p f o r P r e c i s e C o n t r o l o f R a t e o f O u t ­

f l o w ...E . P . White 668

G l a s s - B l o w i n g A c c e s s o r i e s . . . Walter A . Carlson 644

T h e A m erica n C h e m ic a l S o c ie ty a ssu m es n o r e sp o n sib ility for th e s ta te m e n ts a n d o p in io n s a d v a n c e d b y c o n tr ib u to r s to it s p u b lic a tio n s .

P u b l i c a t i o n O ffic e : E a s t o n , P a .

E d it o r i a l O f f ic e : R o o m 7 0 6 , M i lls B u i l d i n g , W a s h i n g t o n , D . C . A d v e r t is in g D e p a r t m e n t : 3 32 W e s t 4 2 n d S t r e e t , N e w Y o r k , N . Y . T e l e p h o n e : N a t i o n a l 0 8 4 8 . C a b le : J i e c h e m ( W a s h i n g t o n ) T e l e p h o n e : B r y a n t 9 —1130

P u b lis h e d b y t h e A m er ic a n C h e m ic a l S o c ie ty , P u b lic a tio n O ffice, 2 0 th &

N o r th a m p to n S ts., E a s to n , P a . E n te r e d a s s e c o n d -c la s s m a tte r a t th e P o s t Office a t E a s t o n , P a ., u n d er th e A c t o f M a rch 3 , 1 8 79, as 4 8 t im e s a y ea r . In d u s tr ia l E d it io n m o n th ly on th e 1 st; A n a ly tic a l E d it io n m o n th ly on th e 1 5 th ; N e w s E d it io n on th e 1 0 th a n d 2 0 t h . A c c e p ta n c e for m a ilin g a t sp e c ia l ra te o f p o sta g e p r o v id ed for in S e c tio n 1 1 03, A c t of O c to b e r 3 , 1 9 17, a u th o r iz e d J u ly 13, 1918.

A n n u a l su b s c r ip tio n r a te s: In d u s t r i a l a n d En g i n e e r i n g Ch e m i s t r y

c o m p le te SG.00; ( a ) In d u s t r i a l Ed i t i o n $ 3 .0 0 ; ( 6 ) An a l y t i c a l Ed i t i o n

$ 2 .5 0 ; (c) Ne w s Ed i t i o nS I .5 0 ; (a) a n d (6) to g e th e r , 5 5 .0 0 . F o r e ig n p o sta g e t o c o u n tr ie s n o t in th e P a n A m er ic a n U n io n , $ 2 .4 0 , (a) S I .2 0 ; (6) SO.6 0 ; (c) S 0 .6 0 . C a n a d ia n p o sta g e o n e-th ir d th e s e ra te s. S in g le co p ie s: (a) $ 0 .7 5 ; (6) $ 0 .5 0 ; (c) SO. 10. S p e cia l ra te s t o m em b ers.

N o cla im s can b e a llo w e d fo r co p ie s o f jo u rn a ls lo s t in t h e m a ils u n less su ch c la im s are r e c e iv e d w ith in s ix t y d a y s o f t h e d a te of issu e , a n d n o cla im s w ill b e a llo w e d for issu e s lo s t as a re su lt o f in su fficie n t n o tic e of c h a n g e of a d d ress. (T e n d a y s' a d v a n c e n o tic e re q u ir ed .) “ M iss in g fro m files"

c a n n o t b e a c c e p te d as t h e r e a so n for h o n o r in g a cla im . C h a rles L . P a r so n s, B u sin e ss M a n a g er , M ills B u ild in g , W a s h in g to n , D . C ., U . S. A .

4 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 10, NO. 11

B Y S P E C I F Y I N G

BRAND

F IN E L Y G R O U N D S U R F A C E S A R E KEPT U N IF O R M B Y S P E C IA L G R IN D IN G T O O L S

— C O N S T A N T L Y C H E C K E D - F R E Q U E N T L Y R E C O N D IT IO N E D

E X T R A H E A V Y B E A D E D E N D - F O R L O N G

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H E A V Y U N IF O R M W A L L

C O N S T R U C T IO N T H R O U G H O U T FO R G R E A T E R M E C H A N IC A L

S TR E N G TH

S T A N D A R D T A P E R ( T )

G R O U N D G LA SS J O IN T S A N D CO N NEC TIO N S

E N D FIN ISH , FIR E -P O LIS H E D

F O R E X T R A S TR E N G TH

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tions, tu rn to your new “ P y rex ” L aboratory Glassware Catalog. T here you will find new listings, im p o rtan t new improvements and new low prices.

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Our facilities for the design and fabrication of special ap p a ratu s w ith “ P y rex ” b ran d T Jo in ts are always available. Y our inquiries will receive our prom pt atten tio n . All stan d ard item s are available through your regular source of supply.

“P Y R E X ” is a registered trade-mark and indicates m anufacture by

CORNING GLASS WORKS

NEW C A TA LO G AVA ILA BLE T O SC IE N T IS T S .- E I)l G A T O R S , E X E C U T IV E S

NOVEMBER 13, 1938 ANALYTICAL EDITION 5

Who U ses

" W h a t m a n " ?

F i l t e r P a p e r s s e r v e a v a r ie t y o£ M a s t e r s . Y o u w i l l f in d t h e m i n t h e s t o r e r o o m s a n d o n t h e b e n c h e s o£ g r e a t U n iv e r s it ie s , a n d i n t h e b a s e m e n t la b o r a t o r y t h a t m u s t s e r v e s o m e s m a l l C o lle g e u n t i l t h e r i c h a l u m n u s d ie s .

C h e m i s t s a n a l y s i n g C o p p e r O r e s i n t h e h e a t o f t h e t r o p ic s o r G o ld s o ­ l u t i o n s u n d e r t h e N o r t h e r n L ig h t s , S t e e l C h e m i s t s i n t h e s m o k e o f P i t t s b u r g h , T e c h n i c i a n s i n t h e W h it e T ile d H o s p it a l la b o r a t o r ie s , a ll u s e W H A T M A N .

T h e r e m a y b e a g r a d e t h a t w i l l s o lv e y o u r d i f f i c u l t f i l t r a t i o n p r o b le m . W h y n o t i n v e s t i g a t e ?

Samples await your request H. REEVE ANGEL & C O ., INC.

7-11 SPRUCE ST., NEW YORK, N. Y.

6 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 10, NO. 11

Select American Chemical Society Monographs for your (Elm stm as (Sift

A partial list of the more recent Titles

4 4 ♦ 4 4 4 P R O P E R T IE S OF GLASS. George W.

M orey. (No. 77). 111. 571 p ...$12.50 M O D E R N M E T H O D S O F R E F IN IN G L U B R IC A T IN G OILS. V. A. Kalichevsky.

(No. 76.) 111. 240 p ... $6.00 P O L Y M E R IZ A T IO N A N D IT S A P P L IC A ­

T IO N S IN T H E F IE L D S OF R U B B E R , S Y N T H E T IC R E S IN S , A N D P E T R O L E U M . R o b ert E . B urk, Archie J. W eith, H ow ard E.

Thom pson, and Ira W illiams. (No. 75.) 111.

312 p ... $7.50 C H E M IS T R Y A N D T E C H N O L O G Y OF

R U B B E R . E d ited b y C arroll C. D avis and Jo h n T . Blake. Published under the auspices of the R ub b er Division of the A m erican Chemi­

cal Socicty. (No. 74.) 111. 944 p ...$15.00 R E A C T IO N S OF P U R E H Y D R O C A R B O N S.

G ustav Egloff. (No. 73.) 111. 897 p. . . . $16.75 CARBO N D IO X ID E . E . L. Quinn an d C. L.

Jones. (No. 72.) 111. 294 p ... $7.50 C O R RO SIO N R E S IS T A N C E OF M E T A L S A N D ALLOYS. R . J. M cK ay and R . W orth­

ington. (No. 71.) 111. 492 p ... $7.00 T H E C H E M IS T R Y OF N A T U R A L P R O D ­

U C T S R E L A T E D T O P H E N A N T H R E N E . L. F . Ficser. Second E dtion. (No. 70.) 111.

456 p ... $7.00 SU L F U R IC A C ID M A N U F A C T U R E . A.

M . Fairlie. (No. 69.) 111. 656 p ... $9.75 T H E N IT R O G E N SY ST E M O F C O M ­

P O U N D S. E dw ard C urtis F ranklin. (No.

68.) 33 C hapters. 111. 339 p ... $7.50 A R S E N IC A L A N D A R G E N T IF E R O U S C O P P E R . J . L. Gregg. (No. 67.) 111. 192 p... $4.00 E L E C T R O K IN E T IC P H E N O M E N A A N D T heir Application to Biology and Medicine.

H arold A. Abram son. (No. 66.) 111. 332 p. $7.50 T H E R A P E U T IC A G E N T S O F T H E Q U IN O ­

L IN E G R O U P. W . F. Von Oettingen. (No.

64.) T ables and charts. 304 p ... $6.00 P H Y SIO L O G IC A L E F F E C T S O F R A D IA N T E N E R G Y . H en ry Laurens. (No. 62.) 111.

616 p ... $6.00

C A TA LY T IC O X ID A T IO N O F O R G A N IC C O M PO U N D S IN T H E V APOR PH A SE . L. F. M arek and D. A. H ahn. (No. 61.) 111.

486 p ... $9.00 F R E E E N E R G IE S OF SO M E O R G A N IC CO M PO U N D S. G. S. P ark s and H . M.

H uffm ann. (No. 60.) 111. 249 p ... $4.50 F IX E D N IT R O G E N . E d ited by H a rry A.

C urtis. (No. 59.) 111. 517 p ... $12.00 V E G E T A B L E FA TS A N D OILS. T heir

sources, characteristics, composition, proper­

ties and uses. George S. Jam ieson, P h.D .

(No. 58.) 444 p ... $6.50 K IN E T IC S OF H O M O G E N E O U S GAS R E ­

A C TIO N S. Louis S. Kassel, P h .D . (No. 57.)

330 p ... $.650 N U C L E IC A C ID S. P. A. Levene an d Law ­

rence W . Bass. (No. 56.) 337 p ... $4.50 D IE L E C T R IC C O N S T A N T A N D M O L E C U ­ LA R S T R U C T U R E . Charles Phelps Sm yth.

(No. 55.) 224 p. 31 diagram s ... $4.00 D E V E L O P M E N T O F P H Y S IO L O G IC A L C H E M IS T R Y IN T H E U N IT E D STA TES.

Russell H . C hittenden. (No. 54.) 427 p. . . $4.50 B E A R IN G M E T A L S A N D B E A R IN G S .

W . M . Corse. (No. 53.) 111. 383 p ... $5.25 D IA TO M A C EO U S E A R T H . R o b ert C al­

vert. (No. 52.) 111. 256 p ... $4.00 T IN . C. L. M an tell. (No. 51.) 111. 366 p. $5.25 PY R O L Y SIS O F C A R BO N C O M PO U N D S.

Charles D ew itt H u rd . (No. 50.) III. 807 p. $9.50 IN D U S T R IA L D E V E L O P M E N T OF SEA R LES L A K E B R IN E S . Jo h n E. Teeple.

(No. 49.) 111. 182 p . . : ...

T H Y R O X IN E . E dw ard C. K endall. (No.

47.) 111. 265 p ...

SO LU B LE S IL IC A T E S IN IN D U S T R Y . Jam es G. Vail. (No. 46.) 111. 443 p. . . . M O L E C U L A R R E A R A N G E M E N T S . C.

W. P orter. (No. 45.) III. 161 p ...

$2.25

$4.25

$7.25

$3.00

S e n d for our complete list

REINH O LD PUBLISHING C O R P O R A T IO N , 330 W . 42nd Street, New York, U .S .A .

'■■•v.'

, K S , e N ? s I C o l o r C o ,i i p a i i s o i i , ViJ

S â t e t & s

ofeolor? b n llla n c e »„d n ü n ta a l am ount

2 J H f D O W L E S S Bottoms.

NOVEMBER 15, 1938

ANALYTICAL ED ITIO N

f r n T i i r YLU^ SaXe:^ueaw ithiiquidand

tn1-!o ¿ e P, USmg,a ^ h t so u rce b e n e a th the tube, th ere a re no dark spots. There is no dis­

tortion of transm itted light by the bottoms.

3 alha^ CaWKr f 0n line5 a re NOT m le d with b lu e glass. W hite is used instead, since the b lue color m ight interfere w ith color tests.

4 Fully a n n ealed (strain-free).

5 The usual high d e g re e of Kimble EXAX a c cu ­ rac y is assured.

IBl a M

■:

I 0 U1 F 0 R W

When furmshedm ^ ^ east^ u^ e 3 ei not uniformity that fee g otherwise speci vary more than 5 ^ gets oi 6.

tied, tubes are supphe Sc£jc t ngth V o Outside manx.

so ml. 25 mm. 2Q0

100 200

50-100 32

S c a l e « « n i

125-145 xnm.

145-170 145-170

T a

(IV* mm. for the 50 ml., Length

» U I S ““

g l O O 2 » 325

O ther types of Kimble Color Comparison Tubes are shown in ihe com plete Exax Catalog. Copy mailed on request.

S to c k e d b y leading' la b o r a to r y s u p p ly h o u se s th ro u g h o u t th e U n i t e d S t a t e s a n d C a n a d a.

— • * T h e V i s i b l e G u a r a n t e e o f I n v i s i b l e Q u a l i t y . * .

KIMBLE G LA SS COM PANY . . . . v i n e l a n d n j

N E W Y O R K - . C H . C A G O - . P H . L A D E L P H . A ' J *

8 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 10, NO. 11

LEEDS & N O R TH RU P

U N I V E R S A L pH I N D I C A T O R

D IR E C T R EA D IN G W IT H GLASS, Q U IN H YD RO N E, H YD RO G EN OR O T H ER E LE C T R O D E SY STEM S

4 9 I 6 - C

U NIVERSA L p H IN D IC A T O R , L eed s & N orthrup. A self-contained, po rtab le, direct reading p o ten tio m e ter electrom eter, inco rp o ratin g a thoroughly shielded stage of therm ionic am plification.

S uitable for use w ith Glass, Q uinhydrone, H ydrogen or o th er electrode system s hav in g resistances as high as 1000 megohm s.

R ange 0 to 13 p H or 0 to 1.1 volts. L im its of erro r of a d ju stm e n t: of p H scale, ± 0 .0 5 p H (ex­

clusive of a n y erro r in th e s ta te d p H of th e buffer so lu tio n ); of voltage scale, 1 0.0037 vo lt. E rro r due to control c u rre n t is less th a n 2 m illivolts p er 1000 m egohm s in m easured circuit. M easurem ents on the p H scale are reproducible w ithin 0.02 pH . F u ll accuracy is o b tain ab le in the presence of rela­

tive h u m id ity up to 95% .

A continuously adjustable dial provides for temperature compensation from 0 to 50°C. When used with the glass electrode system regularly furnished, setting the dial of the temperature compensator to the temperature of the sample adapts the entire pH scale to measurements at that temperature. This also applies if a quinhydrone electrode is substituted for the glass electrode. The pH scale is direct reading with any form of calomel cell such as saturated, normal or tenth normal;

and with any pH electrode following the Nernst equation, provided the instrument is standardized at the operating tempera­

ture.

The voltage scale adapts the instrument for use in oxidation-reduction potential measurements and in current and re­

sistance determinations.

The sealed glass electrode supplied with the instrument is of a new, small rugged type, and can be safely inserted in heavy pastes, cheeses, meats, etc. Only 5 ml of sample is required. A thermometer reading from 0 to 60°C is conveniently mounted on the electrode holder. The electrode compartment is shielded.

Accessories are available for use in making glass electrode or other high resistance measurements outside the shielded compartment. These consist of a holder for the electrodes, shielded leads 36 inches long, and a shield for use with the holder.

Complete with galvanometer system, Eppley standard cell, batteries, etc., in mahogany case 14H inches long X 9%

inches wide X 10 inches high, weight approximately 26 lbs.

4 9 1 6 -C . U n iv e r sa l p H In d ic a to r , L e e d s & N o rth ru p , aa a b o v e d e scrib e d , c o m p le te in ea se w ith s e a le d g la ss e le c tr o d e , referen ce e le c tr o d e , th er­

m o m eter 0 to C 0°C , sa m p le cu p 10 m l c a p a c ity , o n e g r a d u a te d t e s t tu b e 2 0 m l in V jth s, n in e p la in t e s t tu b e s 150 X 18 m m , ru b ber s to p p e r s, a n d o n e b o t t le each of 4 oz. P o ta s s iu m C h lo rid e, c r y s ta ls , 2 o z . Q u in h y d ro n e , 4 oz. B u ffer S o lu tio n (P o ta s s iu m A cid P h th a la te S o lu tio n ), a n d 3 1 'i o z. I n d ic a tin g D r ie r it e ... 2 i ° \ 00 C o d e w o r d ... F a l n e

P am phlet giving m ore detailed, description o f th e L. & N. Universal p H Indicator and accessory e q u ip m e n t, s e n t upon request.

ARTHUR H. T H O M A S COMPANY

R E T A IL —W H O L E SA L E — E X P O R T

L A B O R A T O R Y A P P A R A T U S AN D R E A G E N T S

W E S T W A S H IN G T O N S Q U A R E P H IL A D E L P H I A , U .S.A .

C ab le A ddress, “ B a la n c e ,” P h ila d e lp h ia

INDU STRIAL and ENGINEERING CHEM ISTRY

A N A L Y T IC A L E D IT IO N ♦ H a r r is o n E . I I o w c , E d ito r

Spectrographic Analysis o f B iological Material

Lead, T in , A lu m in u m , C opper, and Silver

JACOB CHOLAK a n d ROBERT V. STORY

K ettering L aboratory of Applied Physiology, U niversity of C in cin n ati, C incinnati, Ohio

T

tending quantitative spectrum analysis and have resulted in an increased application of emission spectrography to studies of trace metals in biological material (1-4, 6 ,1 3 ,1 4 ,1 6 ,1 9 -2 1 , 23,26, 27, 29, S3, 34). The purpose of this paper is to present a method for the simultaneous determ ination of lead, tin, aluminum, copper, and silver in biological m aterial and to call attention to certain improvements in procedure which have been introduced since the authors’ earlier publications (2-Jf).

P h o t o m e t r y

The earlier method of photom etry (2, 3), which gave suf­

ficiently accurate results (5) b u t was applicable only to rela­

tively low concentrations of metals, has been replaced after a study of other technics (10, 11, 13, 15, 28, 30) by the method of Preuss (25). This method, which employs the Hansen gage (17) to incorporate the blackening mark in the analytical spectrum, extends the analytical range, thereby reducing the dilutions otherwise required" to handle relatively high con­

centrations of metals. However, a modification by means of which determinations of opacity could be substituted for determinations of density was found to be advantageous in the evaluation of very weak lines. This modification in­

volves adherence to the authors’ earlier method (2, 3) of deal­

ing directly with faint lines instead of attem pting to isolate and concentrate the test metal (2).

In applying the modification, the quantity of internal stand­

ard used m ust be such as to produce a standard line the den­

sity of which is below 0.30 (opacity of 2) in a t least two steps of the spectrogram produced by means of the step sector.

The measured opacities (galvanometer reading of emulsion/

galvanometer reading of line) for the two weak steps of the standard line are plotted as a straight line against the relative exposures of the steps. The opacities for the test line are also plotted and the distance between the two lines a t a base opacity (1.30) can then be correlated with the concentrations of the test metal (Figure 4). Figure 1 is a photograph of dupli­

cate spectra with faint test lines and Figure 2 illustrates the method of obtaining the separations.

P b X 2833.07 B i X 289S.1

a I T ' 1 ' ■ 1 ... i i .

4 •

j \ I i • : 1

! . ! j

' . I f

z •

1 i l

1 1

•

a

4

2 . I

II

n ii

_ i i _ . j F i g u r e 1

619

620 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 10, NO. 11 The foregoing procedure is employed in the case of spectro­

grams in which the test lines appear in not more than three exposure steps. When the line is present only in the maxi­

mum exposure step, the plot is made by assuming an opacity of 1.0 for the next lower step. When the test lines appear in three or more steps, the method is identical w ith th a t de­

scribed by Strock (SO) in which the intervals of separation

Fig u r e 2

between the density curves for the test and standard lines a t a base density of 0.30 are correlated w ith the logarithms of the concentrations (Figure 3). In borderline cases the choice of method depends upon whether or not the density curve for the test line can be accurately extrapolated to the base density of 0.30; when the density of the te st line in the high­

est exposure step is less than 0.20, more accurate results can be obtained by resorting to the data on opacities.

A p p a r a tu s

The spectral region employed (2 6 0 0 A. to 3 5 0 0 A.) is photo­

graphed with the large Bausch & Lomb quartz Littrow spectro­

graph, a spherical quartz lens being used between the slit and the light source. Persistent lines of magnesium, manganese, iron, nickel, chromium, and zinc which also occur in this region pro­

vide means for the inclusion of these metals within the scope of the method.

As in previous work (2-4.) the source of excitation is a direct current arc between graphite electrodes. This source and its modification involving the cathode layer effect (22) are generally the most satisfactory means for volatilizing the minute quantities of metals usually encountered in biological material. Other sources, such as various sparking procedures (7, 8,15,16, 82), the alternating current arc (7, 9), the “Abreissbogen” (15), or the flame (21), result in a lowered sensitivity of detection which off­

sets the other advantages of their use.

The graphite electrodes (0 .7 8 cm., 0 .3 inch, in diameter) are prepared so that the positive rod, 4 0 mm. in length, contains a

crater 3 mm. wide by 10 mm. deep into which the sample is intro­

duced, while the negative, 70 mm. in length, is sharpened with a pencil sharpener to a fine point. This pointed electrode aids in centering and confining the arc, thereby reducing its tendency to wander.

Among other impurities, graphite electrodes, as purchased, con­

tain aluminum and copper in such quantities as to necessitate their removal. Preliminary arcing for 1.5 minutes accomplishes this but also impairs the subsequent effectiveness of the electrodes because of increased arc wandering. A satisfactory method of purification consists in steeping the properly cut rods in a mix­

ture of equal parts of distilled hydrochloric and nitric acids maintained at 70° C. over a period of 48 hours during which the bath is changed 4 or 5 times. This treatment is followed by a corresponding period of immersion in 4 or 5 changes of triple­

distilled water also at 70° C., after which the electrodes are heated for 1 hour at from 900° to 1000° C. in an electric muffle furnace. Only boron, silicon, and traces of magnesium and . vanadium then remain as impurities, and these may be reduced

by other methods of purification (15, 18, 24, 85).

A sector for use in this work was designed with a relative ex­

posure factor of 2 (log 0.30), in seven steps, each exposing a 2.5- mm. length of the slit of the spectrograph. The sector is pro­

vided with a slotted plate that can be adjusted to eliminate any number of steps. A five-step exposure was found to be the most practical and was used in this study. The sector exposes the slit over but one-third of its circumference. (Sectors with higher total exposures are useful in analyzing less persistent lines than those referred to herein. A suitable sector for such lines is one which is cut out on both sides so as to double the total exposure given the slit of the spectrograph.)

Density and opacity measurements were obtained with the Bausch & Lomb nonrecording densitometer. In order to meas­

ure 2.5-mm. sections of the spectrograms, it was necessary to increase the magnification by providing a longer arm for the projection mirror than th at supplied with the instrument.

Ta b l e I . Sp e c t r a l Li n e s

M e ta l X L in e I n te rn a l S ta n d a rd X L in e

L ea d 2 8 3 3 .0 7 B is m u th 2 8 9 8 .1

L ea d 2 S 7 3 .4 B is m u th 2 8 9 8 .1

Tiu ^{2 8 4 0 .0} B is m u th 2 8 9 8 .1

A lu m in u m 3 0 8 2 .1 6 C o b a lt 3 0 8 2 .6

C o p p er 3 2 7 3 .9 6 C o b a lt 3 2 8 3 .4 5

S ilv e r 3 2 8 0 .6 7 C o b a lt 3 2 8 3 .4 5

W o r k in g C u rves

The working curves m ay be obtained from solutions pre­

pared by adding the test metals and the internal standards to a salt solution of such composition as to be readily adaptable to th a t of the materials handled, with respect to inorganic salts.

The m aterial chosen as the base was the synthetically pre­

pared ash of normal urine as described elsewhere (2). A double internal standard, consisting of 5 mg. of bismuth and 100 mg. of cobalt per 100 ml. of solution, was employed.

Table I lists the spectral lines of the metals and the corre­

sponding lines of the internal standard, as used to derive the calibration curves.

Figures 3 and 4 illustrate the family of calibration curves used in this study. The extent of the analytical range for each line when used in either the density or opacity technique can be observed from the graphs.

P r e p a r a t io n o f S a m p le s

The contaminations attending the chemical treatm ent of samples have been reduced to quantitative insignificance by employing purified acids and triple-distilled water (2) and by working in a laboratory equipped with a dust-removal sys­

tem. Chemical treatm ents of the samples are preferred be­

cause they perm it the use of solutions which in addition to guaranteeing the homogeneous nature of the samples greatly facilitates the introduction, into the craters of the electrodes, of the small amounts of m aterial employed in the tests.

Urine samples are prepared for analysis by the method de­

scribed previously (4), except that the mixed internal standard (1 ml. = 0.5 mg. of bismuth and 10.0 mg. of cobalt) is added.

NOVEMBER 15, 1938 ANALYTICAL EDITION 621

T a b l e II. Co n c e n t r a t i o n s o f Me t a l s i n Hu m a n Ti s s u e s (C a se A. P . 1 9 3 7 . A g e 75 y ea r s)

✓--- M eta l F o u n d -

T is s u e S a m p le P b Sn A1 C u A g

G ra m s M g . -per 1 0 0 g ra m s fr e s h tissu e

K id n e y 5 0 .0 0 .0 2 0 .0 1 5 0 . 0 2 0 . 2 0 0 .0 0

H e a r t 5 0 .0 0 . 0 1 5 0 .0 1 5 0 .0 0 0 . 1 8 0 . 0 0

B r a in 5 1 .8 0 .0 1 5 0 .0 0 0 . 0 0 2 0 . 4 5 0 .0 0 5

S to m a c h 5 0 .0 0 . 0 3 0 .0 2 0 . 1 4 0 . 0 9 0 . 0 0

L iv e r 5 0 .0 0 . 1 4 0 . 0 3 0 . 0 2 0 . 5 5 0 . 0 0

S p leen 5 0 .0 0 .0 3 5 0 . 0 2 0 .1 2 0 . 0 9 0 . 0 0

S m a ll in t e s t in e 3 2 .0 0 .0 2 5 0 . 0 2 5 0 .1 0 0 . 0 9 0 . 0 0

S k in 1 3 .0 0 .0 2 5 0 .0 1 5 0 . 0 7 5 0 . 0 4 0 . 0 0

L u n g 5 0 .0 0 .0 3 0 . 0 5 5 6 . 6 0 0 . 0 7 0 .0 1 5

C o lo n 2 5 . 0 0 .0 2 5 0 .0 2 5 0 . 1 2 0 . 0 5 0 .0 1

B lo o d 1 3 .0 0 .0 2 5 0 . 0 0 0 . 4 5 0 .1 1 0 . 0 0

U r in a r y b la d d er 2 4 .0 0 .0 1 0 .0 1 0 . 0 6 5 0 . 0 6 0 .0 0 5

G a ll b la d d er 5 . 4 0 .0 1 5 0 . 0 0 0 . 0 2 0 .1 7 0 .0 0 5

M u s c le 1 0 .0 0 .0 0 5 0 . 0 0 0 . 0 4 0 . 1 0 0 .0 0

R ib 5 . 2 0 .3 9 0 . 0 0 0 .0 1 0 .2 1 0 .0 0

F e m u r 9 . 2 3 .5 9 0 . 0 0 1 .0 9 2 . 5 0 0 . 0 0

Other biological materials, excepting spinal fluid, are prepared for analysis by ashing in silica dishes at a temperature not exceed­

ing 500° C. The dried material is ashed directly or after diges­

tion with distilled nitric acid.

The latter procedure reduces the time required for ashing and was employed for all materials excepting feces, which are ashed after drying to constant weight (£). Complete destruction of organic matter may be hastened further by treating the grayish ash with a little distilled nitric acid (1 to 1), evaporating to dryness, and replacing in the muffle furnace for a few minutes.

The ash is dissolved in distilled nitric acid and triple-distilled water. In the case of feces and food samples sufficient distilled hydrochloric acid is added to prevent the formation of meta- stannic acid. From this point the procedure is the same as pre­

viously described, the method of “excess” being employed to alter the solutions so that they conform (within certain limits) to the inorganic salt composition of the salt base adopted for de­

riving the calibration curves (2).

[ The diluent used for this purpose consists of 50 ml. of the salt stock (2), 5 mg. of bismuth, 100 mg. of cobalt, and sufficient triple­

distilled water to make the volume 100 ml. ] Two-tenth milliliter portions removed with a capillary pipet are placed in the craters

of each of two purified electrodes and arced for 2 minutes, the data for the two spectrograms being averaged to determine the quantities of the metals present.

In order to avoid contaminations or losses in handling small samples of spinal fluid, the manipulations are kept at a minimum.

The procedure is to collect or place the sample in a graduated 15- ml. quartz centrifuge tube, note the volume, add 0.1 ml. of dis­

tilled nitric acid for each 1 ml. of spinal fluid, and concentrate in a water bath to one-tenth of the original volume. Following the addition of an equal volume of the salt diluent, 0.4-ml. portions are placed in the electrodes and their arc spectra are photo­

graphed. Such a procedure permits duplicate analyses of sam­

ples as small as 5 ml. in which as little as 0.05 gamma of each metal can be determined quantitatively.

R e s u lt s

In Tables I I and I I I are recorded the findings for a com­

plete series of necropsy specimens and for a number of other materials handled in the laboratory. The accuracy of the technique can be observed from the results listed in Table IV, in which are given the recoveries on duplicate samples prepared by adding known amounts of the metals to the base salt stock.

T a b l e III. C o n c e n t r a t i o n s o p M e t a l s i n B i o l o g i c a l M a t e r i a l ---M e ta l F o u n d —

M a ter ia l P b S n A1 C u A g

M g . M g . M g . M g . M g .

S p in a l flu id F e c e s

R . (2 4 hr.)

< 0 . 0 0 1 / 1 0 0 m l. 0 . 0 0 0 / 1 0 0 m l. < 0 . 0 0 / 1 0 0 m l. 0 . 0 0 1 / 1 0 0 m l. 0 . 0 0 0 / 1 0 0 m l.

1 .1 2 3 .0 0 5 . 2 0 0 . 9 4 0 . 0 4

R . (24 hr.) 2 .0 0 1 2 .4 0 8 . 0 0 2 . 0 0 0 . 0 2

G . (2 4 hr.) 0 .5 6 3 . 0 0 7 . 0 0 1 .0 4 0 .0 3

F o o d (c o m p o s it e ) 0 0 . 1 5 3 . 7 5 1 .5 5 1 .5 9 0 . 0 2

0 . 2 7 1 .1 2 3 . 1 0 1 .8 5 0 . 0 2

0 . 3 5 7 . 8 0 1 2 .0 0

M g . p e r lite r

2 . 3 4 0 . 0 7

U rin e

R . 0 . 0 4 0 .0 1 5 0 . 0 3 0 . 0 6 0 . 0 0

D . 0 .0 1 5 0 .0 0 0 . 0 9 0 . 0 6 0 . 0 0

G . 0 .0 6 0 . 0 0 0 . 0 5

M g . p e r 1 00 g ra m s

0 . 0 6 0 . 0 0

B lo o d

R . 0 .0 5 5 0 . 0 0 0 . 1 0 0 . 1 7 0 . 0 0

D . 0 .0 2 5 0 . 0 0 0 . 0 0 5 0 . 1 3 0 . 0 0

G . 0 . 0 4 0 . 0 0 0 . 0 2 0 . 1 3 0 . 0 0

L iv e r J . M . 0 . 1 2 0 . 1 0 0 . 1 2 0 . 5 0 0 .0 1

° T h is r e p r ese n ts a n e x a c t d u p lic a te o f s u b j e c t ’s fo o d in ta k e o v e r 2 4 -h o u r p erio d .

In order to reduce the effects of m utual contaminations in the individual standard metal solutions, the lowest concentration of each metal was made somewhat higher than th a t encoun­

tered in practice.

Results which are reported as 0.00 in Tables I I and I I I do not signify th a t these metals were absent but only th a t the quantities present were less than 0.005 mg. per 100 grams of tissue; in the case of silver very faint lines could be seen, b u t occasionally the presence of the tin line was doubtful.

T a b l e IV. Re c o v e r i e s o p Kn o w n Am o u n t s o p Me t a l Ad d e d t o Ba s e Sa l t So l u t i o n s

L ea d T in A lu m in u m C o n n er S ilv e r

A d d ed F o u n d A d d e d F o u n d A d d e d F o u n d A d d ed F o u n d A d d e d F o u n d

M g . M g . M g . M g . M g . M g . M g. M g . M g. M g .

0 .0 5 0 . 0 4 3 . 0 0 2 . 9 0 1 .0 0 1 .2 0 0 . 3 0 0 . 2 7 0 . 0 2 0 . 0 3

0 . 0 5 3 . 3 0 1 .0 0 0 . 2 8 0 .0 2 5

0 .3 0 0 .3 2 0 . 0 3 0 . 0 3 0 . 3 0 0 . 2 6 1 .5 0 1 .3 3 0 . 2 0 0 . 1 8

0 .3 1 0 . 0 3 0 . 2 7 1 .4 0 0 . 2 2

2 . 0 0 1 .8 5 0 . 4 0 0 . 3 6 0 .0 3 0 .0 2 0 . 1 0 0 . 0 8 5 0 . 6 0 0 . 6 6

1 .9 5 0 . 3 8 0 .0 2 0 .0 8 5 0 . 7 0

5 .0 0 4 . 7 0 5 . 0 0 5 . 2 0 8 . 0 0 8 . 7 5 0 . 0 3 0 .0 3 0 . 1 0 0 . 0 8 5

4 . 9 0 4 . 7 0 8 . 7 5 0 .0 3 0 . 1 0

Fi g u r e 4

D is c u s s io n

Figures 3 and 4 show th at, of the metals studied, lead and tin m ust be determined with reference to the opacities of the spectral lines when present in quantities below 0.10 mg. per

622 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 10, NO. 11 100 ml. of solution. The test lines of aluminum, copper, and

silver are so persistent th a t their densities can be used over their entire analytical ranges. In the case of copper and aluminum very small quantities present as impurities in either the internal standards or the base salt stock markedly in­

fluence the respective curves in the lower analytical ranges.

This effect decreases as the concentration of the test metal increases and, moreover, it can be determined and compen­

sated for by extrapolating the straight portions of the curves, as shown by the dotted lines in Figure 3.

The base salt stock and the cobalt internal standard stock used in these observations provided contaminations to the extent of Gy of copper and 12y of aluminum per 100 ml. of solution. Treatm ent of the salt stock with hydrogen sulfide (2) removes all but m inute quantities of copper, which may be further reduced by treatm ent w ith sodium diethyldithio- carbamate (31). The chief source of contamination with copper, however, was the cobalt internal standard (Mallinc- krodt’s analytical reagent cobalt chloride) purification of which by sodium diethyldithiocarbamate or by a dithizone treatm ent (IS) did not prove successful. By means of the former reagent, cobalt is precipitated and extracted with the copper, in the ether (or chloroform) layer, while in the case of the latter reagent the large excess of cobalt over copper pre­

vents the extraction of the copper. The chief source of con­

tam ination w ith aluminum is the salt stock. Thus far, suit­

able methods for the elimination of this factor have not been found. I t is obvious, therefore, th a t in the case of aluminum it is necessary to determine the magnitude of the contami­

nation due to the salts each time the stock salt solution is renewed from new lots of salt. Since excess salts are not added to urine samples, quantities of aluminum below 0.20 mg. per 100 ml. of solution can be determined by applying the extrapolated line.

I t is possible to extend the analytical range for certain of the metals by employing suitable less persistent lines, as in the case of lead, for which the line a t X2873.4 is employed a t concentrations above 4.0 mg. per 100 ml. of solution (Figure 3). Tin, when present in am ounts less than 10 mg. per 100 ml. of solution, also gives a number of lines in the spectral region studied, b u t their persistencies are so little less than th a t of the X2840 line as to give little benefit from their use.

Only a few lines of aluminum and copper are visible, the aluminum line a t X3092.8 being useless because of the presence of a magnesium line a t X3093.05. The copper line a t X3247.55 is probably more persistent than the line a t X3274 but, since the former falls in a region in which a number of narrow bands occur, the latter line is measured w ith greater ease when m inute amounts of copper are present. The only silver line produced by concentrations within the range likely to be encountered was th a t a t X3280.67.

High concentrations of aluminum provided the only seri­

ous difficulties in the analyses. Such samples required fur­

ther dilution and repeated spectrograms. After some ex­

perience w ith the materials to be handled, it was found th a t fecal and food samples which usually contained the largest quantities of aluminum, as well as relatively larger amounts of the other metals, could be so adjusted in the final volumes as to perm it the complete analysis from a single spectrogram.

Only in the case of lung samples which usually contained traces of lead, tin, copper, and silver and appreciable quan­

tities of aluminum was it necessary to make separate analyses for aluminum.

In preparing the samples of known metallic content shown in Table IV, it was found th a t silver chloride was precipitated when silver in excess of 0.10 mg. per 100 ml. was present. So long as the precipitate was finely dispersed, no difficulty was encountered in making the analyses if the portion to be mixed w ith the diluent was removed immediately after vigorous

shaking of the solution. When heavy precipitates were pres­

ent they could be dissolved by the addition of 1 to 2 ml. of 5 per cent sodium thiosulfate solution. Thus far such am ounts of silver have not been encountered in biological material.

W ith the calibration curves starting a t 0.01 mg. per 100 ml.

of solution, and by adjusting the final volumes of the dis­

solved ashed m aterial to one-half or even one-fourth of th a t previously recommended (2), it is frequently possible to de­

termine am ounts of m etal as low as 0.0025 to 0.005 mg. per 100 grams of fresh material.

S u m m a r y

A spectrographic method is described for the simultaneous determination of lead, tin, aluminum, copper, and silver in biological material. Im portant improvements in the method include the use of graphite electrodes which are purified by means of a chemical treatm ent; the use of a step sector which when employed to incorporate the blackening m ark in the analytical spectrum also enables a considerable extension of the analytical range; and the use of opacities in place of densities, which improves the accuracy of evaluating faint spectral lines.

L ite r a tu r e C ite d

(1) B en n etts, H . W ., an d C hapm an, F . E ., A ustralian Vet. J ., 1 3 ,13S (1937).

(2) C holak, J „ In d. En g. C hem ., A nal. E d . , 7, 287 (1935).

(3) I b i d . , 9, 26 (1937).

(4) C holak, J., J . A m . Chem. Soc., 57, 104 (1935).

(5) C holak, J ., H u b b a rd , D . M ., M cN ary , R . R., a n d S tory, R. V., In d. E n g . C hem ., A nal. E d., 9, 488 (1937).

(6) C ruse, K ., a n d S chubert, H ., Z . anal. Chem., 105, 241 (1937).

(7) D uffendack, O. S., an d T hom son, K . B., Proc. A m . Soc. Testing M aterials. 36 (II), 301 (1936).

(8) Duffendack, O. S., W iley, F . H ., an d Owens, J . S., In d. En g. Ch e m., A n al. E d., 7, 410 (1935).

(9) D uffendack, O. S., and Wolfe, R. A., Ibid., 10, 161 (193S).

(10) D uffendack, O. S., Wolfe, R . A., an d Sm ith, R . W ., Ibid., 5, 226 (1933).

(11) E isenlohr, F ., and Alexy, K . , Z . physik. Chem., A179, 241 (1937).

(12) Fischer, H ., Angew. Chem., 50, 919 (1937).

(13) F oster, J . S., and H orto n , C.-A., Proc. Roy. Soc. (London), B123, 422 (1937).

(14) G erlach, W ., an d G erlach, W ., “ C linical and P athological A p­

plications of S pectrum A nalysis,” London, A dam H ilger, 1934.

(15) G erlach, W ., an d Rollw agen, W ., Metallwirtschaft, 16, 1083 (1937).

(16) G erlach, W ., R ollw agen, W ., an d In to n ti, R ., Arch. path. A n a l.

( Virchow’s), 301 ( I II), 588 (1938).

(17) H ansen, G., Z . P h y s i k , 29, 356 (1924).

(18) H eyne, G., Angew. Chem., 45, 612 (1932).

(19) L em s, S. J., Biochem. J ., 25, 2162 (1931).

(20) L ow ater, F., an d M u rray , M . M ., Ibid., 31, 837 (1937).

(21) L undegardh, H ., " D ie q u a n tita tiv e S pek tralan aly se der E le- m en te,” T eil I I , Jen a, G u sta v Fischer, 1934.

(22) M annkopff, R ., an d P e ters, C ., Z . P h ysik, 70, 444 (1931).

(23) M itchell, R . L., J. Soc. Chem. In d ., 55, 2 6 7 -9 T (1936).

(24) O w ens, J . S., M etals & Alloys, 9, 15 (1938).

(25) P reuss, E ., Chem. Erde, 9, 387 (1935). (C ited by Strock.) (26) R ab in o v itch , I. M ., D ingw all, A., an d M ackay, F. H ., J. Biol.

Chem., 103, 707 (1933).

(27) R am age, H „ Nature, 138, 762 (1936).

(28) Scheibe, G., an d R iv as, A., Angew. Chem., 49, 443 (1936).

(29) S cott, G. H ., an d W illiam s, P . S., A n a t. Record, 64, 107 (1935).

(30) Strock, L. W ., "S p ec tru m A nalysis w ith th e C arbon A rc C ath o d e L ay e r," L ondon, A dam H ilger, 1936.

(31) T o m p sett, S. L., and A nderson, A. B., Biochem. J ., 29, 1851 (1935).

(32) T w ym an, F., an d H itchen, C. S., Proc. Roy. Soc. (London), A133, 72 (1931).

(33) W ebb, D . A., Sci. Proc. Roy. D ublin Soc., 21, 505 (1937).

(34) W ood, F . C., J. Cancer Research, 14, 476 (1930).

(35) Z urrer, T h ., and Treadw ell, W. D ., Hein. Chim. Acta, 18, 1181 (1935).

Re c e i v e d J u ly X, 19 38. F o r th e tw o p r e v io u s p a p ers o f t h is series, se e re fer­

en ce s (2 ) a n d (3 ).

The D eterm ination o f Rhenium

E stim ation in P yrolu site

LOREN C. IIURD1 A N D CLARENCE F. IIISKEY, U niversity of W isconsin, M adison, Wis.

A n a n a ly t ic a l m e t h o d fo r t h e d e t e r m in a ­ t io n o f r h e n iu m in t h e p r e s e n c e o f la r g e a m o u n t s o f m a n g a n e s e d io x id e h a s b e e n d e ­ v e lo p e d a n d d e m o n s t r a t e d o n s y n t h e t ic m ix t u r e s . A n a ly s is o f a r e p r e s e n ta tiv e g r o u p o f p y r o lu s it e s a m p le s fr o m m a n y p a r ts o f t h e w o r ld in d ic a t e d t h a t t h e n a t u r a lly o c c u r r in g m in e r a l c o n t a in s in a p p r e c ia b le a m o u n t s o f r h e n iu m . T h e h i g h e s t c o n ­ c e n t r a t io n o b se r v e d w a s 0 .2 p a r t p er m illio n p a r t s o f m in e r a l.

T

erals in general and pyrolusite in particular has been a controversial question since the tune of the discovery of the element. Although it has been shown (4) th a t some early methods used for isolating rhenium from manganese concen­

trates were unreliable and th a t manganese compounds in general ordinarily contain inappreciable am ounts of the ele­

m ent, evidence indicated th a t pyrolusite from selected sources contained small b u t definite am ounts of rhenium.

During an earlier spectrographic examination (7) of the acid-insoluble sulfide concentrates obtained from a few sam­

ples of western American pyrolusite, evidence was obtained which indicated the presence of rhenium. Routine examina­

tion of about fifty random samples of widespread geographic origin revealed its presence in tw enty-two specimens. Identi­

fication was in m ost cases based upon one or two lines and it was known th a t concentrations were on the border line of the sensitivity of the method. I t was n o t fully realized a t th a t time th a t any method involving identification based upon the appearance of one line of the 3460 A. triplet or the 4880

A.

was hazardous because of the virtual coincidence of iron, manganese, and molybdenum lines, some of which were not recorded in the conventional atlases.

All the samples available for the study had been previously analyzed for elements known to be detrim ental in dry cells of the Leclanchd type and w ith one or two exceptions were found to have normal compositions. Because it is axio­

m atic in the dry-cell industry th a t a chemical analysis of a given pyrolusite does not necessarily prognose its behavior in a cell, all samples had been tested as dry-cell depolarizers.

About half of the samples were of such a nature th a t the cells in which they were incorporated had subnormal shelf lives and were deficient on drain tests. When the results of the spectrographic examination were compared to the electrical data, with b u t three exceptions the samples thought to con­

tain rhenium were unsatisfactory as dry-cell constituents.

Because of this striking correlation, samples of high-grade M ontana pyrolusite were compounded with rhenium dioxide to yield products containing 0.075, 0.0075, and 0.00075 per cent of rhenium. The m aterials along with uncontaminated ore were incorporated in dry cells which were subjected to interm ittent and continuous drain tests. I t was found th a t the cells containing rhenium were inferior to the controls in

x P r e s e n t a d d r ess, 2 2 8 R o se m o re A v e ., G le n sid e , P a .

every respect and th a t the deficiencies were in proportion to the rhenium concentrations^ Figure 1 illustrates the condition of the inner surfaces of the zinc cans a t the end of 72 hours of interm ittent drain through 80 oluns. I t was evident th a t the presence of rhenium in pyrolusite was objectionable if the mineral was to be used in the construction of Leclanchd cells.

The need for an adequate method of quantitative analysis was likewise apparent.

An added stimulus to the development of a method for the analysis of rhenium in the presence of large am ounts of m an­

ganese lies in the possibility th at, if a naturally occurring manganese ore containing rhenium, element 75, can be found, element 43 will likewise be present. The repeated failure of investigators to confirm the isolation and identification (11) of the middle homolog of the manganese-rhenium series lends support to the view th a t its properties are as yet unknown.

H is t o r ic a l

Two general methods have been proposed for the isolation of rhenium from manganese concentrates. Those procedures involving manipulations based upon an assumed similarity

Fi g u r e 1 . Rh e n i u m i n Py r o l u s i t e U p p e r le ft. B laD k

U p p e r r ig h t. 0 .0 0 0 7 5 p er c e n t rh en iu m L o w e r le f t . 0 .0 0 7 5 p er c e n t rh en iu m L o w er r ig h t. 0 .0 7 5 p er c e n t rh en iu m

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