Industrial and Engineering Chemistry : analytical edition, Vol. 18, No. 4

INDUSTRIAL ^{a n d} ENGINEERING CHEMISTRY

A N A L Y T I C A L E D I T IO N

V O L U M E 18, N U M B E R 4 IS S U E D A P R I L 25, 1946 C O N S E C U T I V E N U M B E R S

Assistant to Editor: N . A . PARKINSON

Manuscript Editing: G . G L A D Y S G O R D O N

R. P. C H A P M A N J . R. C H U R C H IL L B. L . C L A R K E

ED ITO R: W A L T E R J. M U R P H Y Associate Editor: L A W R E N C E T. H A L L E T T

Assistant Editors

Manuscript Reviewing: S T E L L A A N D E R S O N

Advisory Board

T. R. C U N N IN G H A M G . E. F. L U N D E L L M . G . M E L L O N

Contributing Editor: R. H . MULLER

Make-up: CHARLOTTE C . SAYRE

R. H . M U LLE R B. L. O S E R H . H . W IL L A R D

E d it o r ia ls ... 217 Optical Methods in Electrophoresis . . L. G . Longsworth 219 Deproteinization by Metaphosphoric A c id — Review of Its

Value for A n a l y s t ...A . A . Horvath 229 Application of Platinum Resistance Thermometry to Some

Industrial Physicochemical Problems . . . Daniel R. Stull 234 Volumetric Quantitative Determination o f— S O O N a Group

in Sodium Benzene S u lfin a te ...Leo Ackerman 243 Determination of 1,2-Propylene G lycol in Ethylene G lycol .

R. C . Reinke and E. N . Luce 244 Estimation of Salts of Weak A cid s by Direct Titration in

M ixed So lv en t... Santi R. Palit 246 Determining Moisture Equilibrium Curves of Hygroscopic

M a te ria ls...Willmer A . Wink 251 Simultaneous Determination of Ethylene and 1,2-Propylene

G lycols . . . . Benj. Warshowsky and Philip J . Elving 253 Colorimetric Determination of Iron in Presence of Large Con­

centrations of Copper and Nickel . . R. H . Greenburg 255 Destruction of Organic Matter in Blood Fibrin and Chroma-

cized M edical Catgut by Wet O x id a t io n ...

G . Frederick Smith 257 Analysis of Mixtures of Meta- and Para-Cresols and Their

Butylated Products . Donald R. Stevens and J. E. Nickels 260 Determination of Cobalt in High-Cobalt Products. Separa­

tion from Iron by Phosphate . R. S. Young and A . J. H all 262

—

Colorimetric Determination of Cobalt with Ammonium Thiocyan ate... R. S. Youns and A . J . H all 264 Most Economic Sampling for Chemical A n a ly s is ...

C . West Churchman 267 Drill Sampling Device for Fish Livers. Precision and A c ­

curacy ...F. B. Sanford and G . C . Bucher 269

M IC R O C H E M IST R Y

Colorimetric Determination of p ,p '-D D T in Technical D D T Saul W . Chaikin 272 Semimicrodetermination of Saponification Equivalent by

Rieman’s Double-Indicator Method . Donald Ketchum 273

N O T E S O N A N A L Y T I C A L P R O C ED U R ES

Isopropyl A lcohol in Cotton Wax Determination . . . . James H . Kettering 275 Preparation of Silica G el for Chrom atography...

Roberta Harris and Arne N . W ick 276 Determination of Small Amounts of 4-V inyl-1-cyclo-

hexene (Butadiene Dimer) in Tetrahydrophthalic A n ­ hydride . . . Benj. Warshowsky and Philip J . Elving 276 Distilling Apparatus for Production of Pure Water . . . .

Frederic E. Holmes 277 Regeneration of Walden Silver Reductor...

Eugene H . Huffman 278 New Type of Reflux Condenser. . W illard T. Somerville 278 Instrumentation in Analysis . . R. H . M u lle r (Advt. Sect.) 25

The Am erican Chem ical Society assumes no responsibility for the statements and opinions advanced by contributors to its publications. V ie w s expressed in the editorials are those of the editors and d o not necessarily represent the official position of the Am erican Chem ical Society.

W e acknow ledge w ith thanks the action of J . T. Baker Chem ical C o . in releasing the front cover of this issue for editorial purposes.

Copyright 1 9 46 by Am erican Chem ical Society.

3 7 ,2 0 0 copiés of this issue printed.

Published by the Am erican Chem ical Society at Easton, Pa. Editorial H e a d ­ quarters: 1 1 5 5 16th Street, N . W ., W ashington 6 , D. C ./ telephone. Republic 5301/

cable, Jiechem (W ashington). N e w Yo rk Editorial Branch: 6 0 East 42nd Street, N e w Yo rk 1 7 , N . Y./ telephone. M urray H ill 2 -46 6 2 . C hicago Editorial Branch:

Room 8 1 9 , 25 E. Jackson Blvd., C h ica go 4, III.; telephone, Wabash 7376. Business O ffic e : Am erican Chem ical Society, 1 155 16th Street, N . W ., Washington 6 , D. C.

A dvertisin g O ffice : 3 3 2 W est 42nd Street, N e w Yo rk 18, N . Y./ telephone,

Bryant 9 -4 4 3 0 . . .

Entered as second-class matter at the Post O ffice at Easton, Pa., under the A c t or March 3, 1 8 7 9 , as 24 times a year— Industrial Edition monthly on the 1st, Analytical Edition monthly on the 15th. A cceptance for mailing at special rate of postage pro­

vided for in Section 1 1 0 3 , A c t of O c to b e r 3 ,1 9 1 7 , authorized Ju ly 13, 1918.

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$ 0 .8 0 . A nalytical Edition prices on request/ special rates to members.

The Am erican Chem ical Society also publishes C hem ica l and Eng ineering News, C hem ica l Abstracts, and Jo u rn a l o f the Am erican C hem ica l So ciety. Kates on request.

LIME-ALUMINA —LI M E-SILICA BALANCE

STARTS IN THE LABORATORY

The cement industry lives largely by its research and control methods. From- the first fall of limestone blasted at the . quarry’s face, to the final test batches from the filling bins, raw materials are constantly analyzed and finished products are searchingly inspected.

For their routine check on silica in the raws,. many cement companies employ a time- saving method which involves the use of Baker’s Analyzed C.P. Perchloric Acid.

The extremely low content of silica and non-volatile matter in this acid makes it preferable for many other tests as well.

Baker’s Analyzed C.P. Ammonium Oxalate is often the chemist’s choice for calcium determination. This reagent is extremely low in non-soluble, non-Volatile and sulphate materials.

Baker’s Analyzed C.P. Chemicals differ from other laboratory chemicals. They have the actual analysis on the label—not mere maximum limits of impurities. This saves the chemist time when making computations.

Baker s distributors welcome every opportunity to serve the cement industry. 'When you order your reagent chemicals from your favorite supplier, be sure to specify "Baker’s Analyzed.”

j . T. B a ke r Chem ical Co., Executive Offices and Plant: Phillipsburg, N. J . Branch Offices: New York, Philadelphia, Boston and Chicago

P u r i t y d e f i n e d — n o t t o

“ m a x im u m lim its “ — but to t h e d e c i m a l b y a c tu a l lo t a n a ly s is . T h a t’s th e s to ry of th e B a k e r 's A n a ly z e d la b e l.

April, 1946 A N A L Y T I C A L E D I T I O N

TODD SC IE N T IFIC SPEC IFIC A TIO N S

PRECISE FRACTIONATION A S S EM B LY

USED BY THE NATIONAL BUREAU OF STANDARDS

A n e ffic ie n t an d versatile lab oratory fr a c tio n a tio n c o lu m n a sse m b ly w ith a n ew m e th o d o f a d ia b a tic te m p era tu re con tro l for co m p lete fr a c tio n a tio n o f m a n y ty p es o f o rg a n ic licpiid m ix ­ tures e ith e r at a tm o sp h e r ic p ressu re or u n d er v a cu u m .

Covered b y U n ited S ta te s p a ten t N o. 2,387,479.

FEA TU R ES:

1. F r a c t i o n a t i o n e f fic ie n c y u p to 50 t h e o r e t i c a l p l a t e s . 2. F r a c t i o n a t i o n c h a r g e s f r o m 2 c e . to 5000 c c . in c lu s iv e . 3. T e m p e r a t u r e r a n g e f r o m r o o m t e m p e r a t u r e t o 100°C.

( 7 5 2 ° F .).

■I. N e w p r e c i s i o n d e v ic e f o r a d i a b a t i c t e m p e r a t u r e c o n t r o l . 5. A t m o s p h e r i c o r v a c u u m f r a c t i o n a t i o n s .

6 . T h r e e i n t e r c h a n g e a b l e f r a c t i o n a t i n g c o l u m n s . 7. I m p r o v e d s p i r a l p a c k i n g f o r s m a l l c o l u m n . 1!. R a p i d f r a c t i o n a t i o n w i t h c o m p l e t e v i s a h il i ly . 9. E a s ily o p e r a t e d w i t h a m i n i m u m o f e x p e r ie n c e . 10. S p e c ia l m a c h i n e d s u p p o r t s f o r a s s e m b l i n g a p p a r a t u s . 11. P r e c is io n c o n t r o l p a n e l f o r o p e r a t i n g t h e c o l u m n ’s ‘• S t a g ­

g e r e d D u a l H e a t i n g U n i t ” a n d s t i l l p o t .

12. S p e c ia l a l u m i n u m a llo y p o t h e a t e r w i t h lo w t e m p e r a t u r e la g .

13. A ll m e t a l p a r t s n o n - c o r r o s i v e to n o r m a l l a b o r a t o r y a t m o s ­ p h e r e .

I I . R a p id l y • a s s e m b le d o r d i s m a n t l e d .

T h is F R A C T IO N A T IO N C O L U M N A SSE M B L Y is the result o f a com prehensive and critical stu d y o f p ractically all significant reports on m ethods and a p p aratu s for precise lab o rato ry fractionations which were published in th e U nited S ta te s, B ritish, French, and G erm an scientific literatu re. In add itio n , the m ethods a n d a p p aratu s surveyed have been subjected to exhaustive exjierim ental te sts in o u r laboratories.

T hese te sts have shown th e need for a v ersatile and efficient fractio n atio n a p p aratu s of more practical design to m eet th e varied fractionation requirem ents arising in chem ical laboratories. T o m eet this need, a new, tru ly versatile and highly efficient lab o rato ry fractio n atio n colum n assem bly was developed w ith several practical features which enable this single assem bly to elim inate th e use o f a n um ber o f fractio n atio n un its for solving different problem s.

T h e use o f th e recom m ended packings in the three interchangeable colum ns o f this new assem bly gives unusually high fractio n atio n efficiencies over co m paratively wide rates of boiling eith er a t atm ospheric pressure o r u n d er vacuum . T hese p articu lar packings elim inate th e freq u en t disadvantages of th e use o f precise reflux ra tio control devices which are in variably bu lk y , tedious to o perate, a n d freq u en tly have large hold-up capacity.

Am ong o th e r features, th e still head of this assem bly overcom es the ubove dis­

ad v an tag es b y having a special co jn p act design, c o n sta n t o p eration, very low hold-up cap acity in o p eration (0.6 cc.), and ease o f control. T h e co m p act design allows th e en tire still head to be com pletely enclosed w ithin th e h e ater ja c k et, thus enabling the en tire fractio n atio n assem bly to o p erate u n d er essentially a d ia b atic conditions ranging from room te m p e ra tu re u p to 752° F . T h is range fa r surpasses th a t o f a n y fractionation equipm ent reported in th e literatu re.

T h e p a te n ted “ Staggered D ual H eatin g U n it” o perates th is assem bly sem i-auto- inatically under p ractically ad ia b atic conditions for m axim um fractionation efficiency w ith com plete visability to all p a rts o f the assem bly. T h is special u n it elim inates the necessity of using fragile and_ expensive silvered vacuum ja c k ets which frequently m ake observations difficult d u ring th e fractionation procoss.

T h e above a n d num erous o th e r practical features o f this fractio n atio n colum n assem bly n o t only enable this eq u ip m en t to be readily o p erated w ith very little experi­

ence b u t also m ake i t a generally useful piece o f lab o rato ry eq u ip m en t for all types of sim ple o r complex m ixtures requiring precise fractio n atio n in a m inim um o f tim e.

T h e num erous practical ad v an tag es o f th is fractio n atio n assem bly are well recognized by the hundreds o f users presently using this equipm ent.

For a d d itio n a l e x p er im en ta l r e su lts , m e th o d s o f o p era tio n , an d d e ta ils , se e a r tic le , “ E fficie n t an d V ersatile L aboratory F r a c tio n a tio n C o lu m n A sse m ­ b ly ,” by F. T o d d , I n d . E n g . C h e m . , A n a l . E d ., V o l u m e 17, p a g e 175, 1915.

W r i t e f o r r e p r i n t a n d T E C H N I C A L B U L L E T I N 100 f o r m o r e d e t a i l e d f r e e i n f o r m a t i o n a n d p r ic e s .

P A R T IA L L IS T OF U SERS:

A m erican C yanam id C o.. Bound B rook, N . J.

A ndrew Jergens Co., C incinnati, Ohio A shland Oil & Refining Co., A shland, K y.

B akelite C orp., B ound B rook, N . J.

C arnegie In s titu te of Technology, P ittsb u rg h , Pa.

Dow C hem ical C o., F reep o rt, Texas H oudry Process C orp., M arcus H ook, Pa.

Jo n es & Laughlin S teel C orp., P ittsb u rg h , Pa.

M erck & Co., In c., R ahw ay, N . J . M onsanto Chem ical C o.. T exas C ity , Texas N atio n al B ureau o f S tan d ard s, W ashington, D. C.

N ational Oil P ro d u cts Co., H arrison, N . J.

N ew Y ork N a v y Y ard , N . Y .

N orw ich P h arm acal C o., Norw ich, N . Y . Q ueen’s U niversity, O ntario, C anada R aym ond L aboratories, In c., S t. P au l, M inn.

Shaw inigan Chem icals L td ., Quebec, C anada S harp a n d D ohm e, Inc., P h ila., Pa.

Shell Oil C o., In c., W ood R iver, 111.

Sw arthm ore College, S w arthm ore, P a.

T hiokol C orp., T ren to n , N . J .

U. S. In d u stria l Chem icals, In c., New Y ork, N . Y.

U niversity of C h attan o o g a, C h attan o o g a, Tenn.

U niversity o f K ansas, Law rence, K ansas U niversity o f Virginia, C harlottesville, Va.

U niversity o f W isconsin, M adison, W is.

W esleyan U niversity, M iddletow n, C onn.

W y andotte Chem icals C orp., W y an d o tte, M ich.

TODD SC IEN TIFIC COMPANY

D e s i g n e r s a n d m a n u f a c t u r e r s o f s p e c ia l s c i e n t i f ic l a b o r a t o r y a p p a r a t u s .

SPRIN G FIELD , PA.

W ATER CH EM ICALS

CONTROL-LAB TESTS

LEEDS & NORTHRUP

M ETALS B O TA N Y

TITRA TIO N

L E E O S <L N O R T H R U P C O M P A N Y , 4 9 2 0 S T E N T O N A V E ., P H I L A . , P Æ

URING IN STR U M EN TS • T E L E M E T E R S • AU TO M A TIC CO N TRO LS * H E A T -T R EĄ T IN G FU RN ACES i t r l A d K -9 R '2 S>

I

I N D U S T R I A 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. 18, No. 4

pH INDICATOR FOR "EVERYBODY"

Here s the pH Indicator for the man who is

a pH expert.

I t s intended to be carried around and used wherever desired in plants as well as labs. I t ’s as sturdy and dependable as a tem perature indicator. I t will stay on the job. To use it, you ju st make 3 simple adjustm ents, then p u t the sample into the

beaker and see where the needle points.

“ Sticky” weather or surroundings won’t affect this Indicator, unless relative hum idity is over 95 and «ambient tem perature is over S5F. I t s fine for laboratories, kitchens, refrigerated chests, packing rooms and power plants.

Solution to be checked can be at any tem perature to 50C (120b)- Thick solutions and “ soft” solids like butter, cheese, dough and many m eats; earth, etc., can be checked almost as easily as slurries or clear liquids.

N earby electrical equipment won’t affect this instrum ent. It requires very little attention. Its scale is substantially longer and easier to read than in any comparable Indicator. Construc­

tional!;,, it s a fine job. Complete with everything necessary for p H measurements.

F urther details are in Catalog E-96(2), sent on request, but if

you have a pH measuring problem we suggest you check with

an L&iN engineer.

?7~'

April, 1946

B. F. Goodrich Chemical CompanY

h a s a v a i l a b l e f o r s a l e t h e s e o r g a n i c c h e m i c a l s

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C r - C f ) : ni B NaphtW p Ptien?'ene W

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... O t t O 00»*7 : Dibenzyl Ether

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... d ? o • • * £ ? ! £ - “

J quantities 13 6 _1 5 30 C 2 HS )(

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... n S 0 ““ 0 : Mixed (Uiphattc T h ia iS » ^ c » , ~ c " s

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O ip h e n ^ p P h e n y oonim«» • quantm «

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Available * lK,U L

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For a d d itio n a l In fo rm atio n p le a s e w rite B. F. G o o d rU h Chem ical C o m p a n y, D e p artm e n t CA -4, R ose B u ild in g, C le v e la n d 1 5 , O h io .

B. F. Goodrich Chemical CompanY

tOSORBENT i-iQUin foi;M

f<" tu« <■*

StSHP* MQNOXI*>n _{o x y c i'.n}

’h^ b u r r i u-;..,

W . CAL SUPPLY com

LSSs»!llltl> *'* -

als u p p l y comp;

^ *»». - • flitvb»*9^

Coniplece information on reagents for gas analysis is given in the new Burrell Catalog 80. If you have not already received your copy, write to Burrell Tech­

nical Supply Co., 1956-42 Fifth Ave., Pittsburgh 19, Pa.

BURRELL

Vol. 18, No. 4

LU S O R B E N T F O R IL L U M IN A N T S

Absorbs all the gases in the illuminants group, i.e., ethylene, propylene, butylene, acetylene, benzene and toluene. Requires fewer passes than fuming sulfuric acid, has no vapor pressure, absorbs less saturated hydro­

carbons and does not attack rubber tubing.

C O S O R B E N T F O R C A R B O N M O N O X ID E Supplied in either liquid or powder form. Has no vapor tension, forms stable compound w ith carbon monoxide, is fast and active. Absorbs ethylene, propylene and acety­

lene, also oxygen slowly.

O X S O R B E N T F O R O X Y G C N

Fast, clean and accurate, removes oxygen in a few passes and forms a stable compound w ith it. Absorbs four times its volume of oxygen. Rises cleanly in the capillary and is slightly acid — preventing sticking stopcocks.

This new combined catalog and manual describes the latest equipment and

methods for gas analysis.

SPEED YOUR GAS ANALYSIS WITH THESE REAGENTS

L U S O R B E N T SLLUMINAJt^

; i c . A.19 7 1 ?

M A N U F A C T U R E R S w orking with formulas that em ploy D D T are invited to come to Du P o n t for technical service! Experience gained by this m ajor supplier of D D T to the armed forces may be o f considerable value to you.

T h at experience plus Du P o n t’s continuing laboratory and field studies m ake it possible to supply you w ith Du P o n t D D T Technical that m easures up to rig id requirem ents.

Because o f the m ethod by which it is m anu­

factured, Du P on t D D T Technical G rade is

uniform ly dependable. It w orks w ell in dry preparations, and dissolves quickly form ing clear solutions.

T o help you form ulate D D T preparations that have a sound basis for com m ercial use, our com plete facilities are available. W e shall be glad to supply w o rk in g sam ples, literature o r to have a representative call.

E. I. du P o n t de N em ours & Co. (Inc.), G rasselli Chem icals D epartm ent, W ilm in g ­ ton 98, Delaw are.

If it has to do with DDT,

work it out with DU PONT!

- _ I V I —

DDT ^Technical

b e t t e r t h i n g s f o r b e t t e r l i v i n g . . . T H R O U G H C H E M I S T R Y

10 I N D U S T R I A 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. 18, No. 4

Orders are being a ccep ted f o r f u t u r e delivery.

CENTRAL SCIENTIFIC COMPANY

S C I E N T I F I C I N S T R U M E N T S

N EW Y O R K T O R O N T O CHICAGO

L A B O R A T O R Y A P P A R A T U S

B O S T O N S A N F R A N C IS C O

The Cenco-Hangosky Apparatus is designed for the electrolytic p ol­

ishing and etchin g of m etal specim ens for m icroscopic exam ina­

tion. Plain carbon and low alloy steels, sta in ­ less steels and a large num ber of the non-ferrous m etals and alloys m ay be pre­

pared for m icroscopic exam ination by this apparatus. T he m eth od is rapid.

The specim en is prepared in the usual m anner carrying through to a 00 or 000 paper and th en w ithin one m in u te given an electrolytic polish and etch.

The apparatus is self-con tain ed , all the required controls for electrolyte, current and tim e being b u ilt in to the u n it. A wide selection in current and tim e is available for both polish in g and etchin g.

The apparatus operates on 115/230 volt, 60 cycle supply.

A N A L Y T I C A L E D I T I O N 11

M a llin ck ro d t St., St. Louis 7 , Mo.

CHICAGO . PHILADELPHIA

CHEMICAL W ORKS

Ù j ^ A e m t c a / f y / à e t e

72 G o ld St., N ew Y o r k 8 , N. Y.

LOS ANGELES • MONTREAL

CAREFUL CHEMISTS INSIST UPON THE BEST. . • t h a t is w h y l e a d i n g la b o r a to r ie s sp ecify M a l l i n c k r o d t A n a l y t i c a l R e a g e n ts , k n o w n for h i g h e s t q u a l i t y a n d for u n ifo r m , d e p e n d a b l e p u rity .

\

S e n d for th e M a ll i n c k r o d t A n a l y t i c a l R e a g e n t c a ta lo g to g e th e r w i t h a n y specific in fo r m a tio n d e s ire d o n M a l l i n c k r o d t c h e m ic a ls to fit y o u r s p e c ia liz e d o p e ra tio n s.

A lw a y s S p ecify M a llin ck rod t R ea g en ts In O rig in a l P ack a g es

S o d iu m O x a la te ( M a ll in c k r o d t) M a g n ifie d to 50 D ia m e te rs

12 I N D U S T R I A 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. 18, No. 4

B E C K M A N p H M E T E R — I N D U S T R I A L M O D E L M

For p H Measurements and Titrations in the Laboratory, Plant or Field

The Model M Beckman pH M eter combines high accuracy with great ruggedness, m aking it suitable for use in the plant or field as well as in the control laboratory. I t is entirely self- contained, extremely rapid and rem arkably simple to operate. I t incorporates a unique Null-type Electronic Potentiom eter Circuit th a t gives in stan t pH readings a t th e touch of a button.

The scale reads from 0 to 14 pH in 0.1 pH divisions. The operating b u tto n m ay be locked down for continuous indication of pH in process control work or for titrations. Readings can be made with only about 10 cc. of sample.

The electrodes perm it measurements on practically any solution irrespective of viscosity, color, suspended solids, oxidizing or reducing agents. The Glass Electrode is factory-filled and sealed, internally shielded, rugged, and ready for in stan t use. The Companion Calomel Electrode is factory-filled and requires a m inimum of upkeep attention. Various types of electrodes can be supplied for specialized uses.

NO. 9682 BECKMAN pH M ETER, INDUSTRIAL M ODEL M. Supplied complete and ready for use in portable hardwood case w ith lock and key. Dimensions: 9" high,

deep, 13j^i"

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m ent w o rk , a n d h a n d le s m a n y in tric a te rm xtures whtch c an n o t b e s u c ce ssfu lly a n a ly z e d b y o th e r m e ans. Its th o ro u gh n e ss ,s show n b y the f a c t th a t in som e c a s e s It h a s d isclo se d the p re se n c e o u n e x p e c te d c o m p o n e n ts w h ich w e r e m issed b y oth er p ro ce ss

n - JL |N U SE •

s e a r c h g r o u p s , c h e m ic a l c o m p a n ie s a n d p r a c t ic a lly e v e ry m a jo r oil c o m p a n y . T w o o f th e se c o m p a n ie s now h o v e 3 mstruments

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IN CUSTOM ER BENEFITS*

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3 . A n a ly z e s m ore s a m p le s w ith less m a n hours p e r s a m p le th a n oth er m ethods o f a n a ly s is .

4 . P ro v id e s lo w e r cost p e r s a m p le . 5 . P ro v id e s h ig h o r d e r o f a c c u r a c y .

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14 I N D U S T R I A 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. 18, No. 4

H E V I D U T Y E L E C T R I C C O M P A N Y

TR EA TI N G F U R N A C E S

M I L W A U K E E

U ^NIVERSITY laboratories are called upon to heat treat m any different items in carrying on research and experim ental work. The illus­

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Hevi Duty Box Furnaces have a large fle xib ility of use—an accurate w ide

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HD-441 details the ad van tages of these furnaces— send for your copy.

A N A L Y T I C A L E D I T I O N

CHICAGO APPARATUS COMPANY CHICAGO ^2^11 LINOIS

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I N D U S T R I A 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. 18, No. 4

* p in g ef

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The latest development in Refrigerated Centrifuges, the International Model PR-1 offers the laboratory analyst practically all of the advan­

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W idth 28" Length 44" Height 42" W eight 850 lbs.

I N T E R N A T I O N A L E Q U I P M E N T C O M P A N Y

B O S T O N 3 5 , M A S S A C H U S E T T S

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C opy o f p a m p h le t EE-96 giving m o re d eta ile d d e sc rip tio n o f th e S to r m e r V isc o sim eter, to g e th e r w ith e x te n d e d b ib lio g ra p h y, s e n t u p o n re q u est.

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R E T A I L — W H O L E S A L E — E X P O R T

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Cable Address, “ Balance” Philadelphia

I N D U S T R I A 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. 18, No. 4

STORMER VISCOSIMETER. For determining viscosities of a wide variety of materials.

Consisting primarily of a cylindrical — or other type — rotor which is immersed in the sample placed in the test cup and maintained a t a desired tem perature by means of a surrounding water or oil bath. The rotor is driven by a falling weight through a series of gears, and a revolution counter is attached to the spindle of the rotor.

Relative viscosity is obtained by dividing the tim e required for the rotor to make a definite number of revolutions in the m aterial under examination by the time required for th e rotor to make th e same n um berof revolutions in distilled water, or other reference, using the identical procedure, a t the same tem perature, and w ith th e same operating weight.

Absolute viscosities can be determined and recorded in centipoises by th e use of a calibration chart which can be readily prepared by the user. See “Chemical Engineers’ Handbook,” John H. Perry, Editor, 2nd edition ( New York, 1941),

p. 15S5. ;

General Purpose Outfit. W ith cylindrical rotor and test cup provided w ith two side vanes, central baffle and ther­

mometer holder. Weight box is filled with lead shot and, when filled, weighs approximately 153 grams; weight when em pty is approximately 28 grams, so th a t the operating 'weight can be adjusted within these limits by removing or adding shot.

P aint Testing Outfit. W ith submerged paddle type rotor and set of slotted weights. A standard one-pint can is used as the container, for the sample and replaces the test cup. I t is supported on a movable shelf. This is the outfit suggested and used by Krebs Pigment & Color Corporation for testing paint consistency, and adopted by A.S.T.M. for standard method D-562-44 for determining the consistency of exterior house paints and enamel type paints.

Code W ord 7649. V isco sim eter, S to rm e r, G e n eral P u rp o se O u tfit, as a b o v e describ ed , w ith cy lin d ric a l ro to r a n d te s t c u p w ith tw o sid e v an es

c e n tra l baffle a n d th e rm o m e te r bolder, co m p lete in case w ith th e rm o m e te r a n d d irectio n s fo r u s e . ... 145.00 Letok 7649-H . V isco sim eter, S to rm e r, P a in t T e s tin g O u tfit, as a b o v e describ ed , w ith su b m erg ed p a d d le ty p e ro to r, th e rm o m e te r, p la te

to ho ld th e c an oi p a in t a n d s e t of s lo tte d w eights 25 g ram s to 1 kilo, c o m p lete in case, w ith K re b s co n sisten cy c h a r t 138.90 L e u e k

7649-K . D itto , b u t c a lib ra te d b y K rebs s ta n d a rd m e th o d 146.40 Leu/6

IN D U STRIAL ^{a n d} EN G IN EER IN G CHEM ISTRY

P U B L I S H E D BY

C H E M I C A L S O C I E T Y A L T E R J. M U R P H Y ,

E D I T O R

Editorial Policies

N

is certain in the field of chemistry but change. Certainly the- field of analytical chemistry has been no exception during the past decade, although perhaps the changes, revolutionary as they are to the analyst, have not been given the spectacular recognition accorded new developments in industrial chemistry.

The editorial policies of the

have been determined solely on the basis of meeting promptly and efficiently the changing require­

ments of the analytical chemist and analytical chemistry. The innova­

tions th a t should be introduced have been the subject of many earnest deliberations by the editors and the Advisory Board of the

Ed i t i o n.

This is particularly true of the past three years, when the board

has been active and has m et at regular and frequent intervals.

A statem ent a t this time outlining the present aims and purposes of the journal will serve a most useful function, clarifying for our readers the views and poficies of the editors. Your editor, Associate Editor L. T.

Hallett, and Assistant Editors G. Gladys Gordon and Stella Anderson have cooperated in the preparation of three statements which we hope will be read, digested, and commented on. The first, discussing the scope of the journal, appears on page 218 of this issue; the second, describing style requirements, will be published in the M ay issue, and this will be followed by a detailed explanation of the reviewing system which will be printed in the June number.

217

218 I N D U S T R I A 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. 18, No. 4

Sco p e of the A n a ly tic a l Edition

W

a paper is written for publication, the

author must decide to which journal it may most suitably be Sent. Some authors make a conscious effort to see th a t the type and style of the article con­

form to the standards or scope of the journal chosen, as they interpret them; others, it would appear, give little thought to this.

When the

was established in 1929, it was intended to serve the analytical chemist by segregating for him worth while contributions in analytical methods and improvements in analytical apparatus in the broad field of industrial and engi­

neering chemistry. While applied analysis has re­

ceived much attention during succeeding years, the journal has become much broader than its original con­

ception. This, together with the expanded interests of the analytical chemist due to the development of new techniques and instruments, gives point to a short discussion for the guidance of authors on the types of papers which the editors of the

consider most suitable, so th at the publication may better serve as the journal for analytical chemistry in all its branches.

1. A paper may present an improved or new pro­

cedure for the analysis or testing of some element, com­

pound, or property, details of which must be accurately presented, so th at others can duplicate the results.

The tools used may be chemical or physical, and the procedures may deal with organic, inorganic, physical, or biological chemistry. The physical chemistry, in many cases, may approach pure physics.

2. A review paper may be invited or submitted.

Its purpose should be critical evaluation of work in the given field during a specified period, rather th an listing references with a brief abstract, for this is more strictly a bibliography. A bibliography is im portant if it is complete, and can be invaluable as an aid in research, but, in most cases, is necessarily so specialized as to be of interest to only a limited number of investigators and consequently does not often find a place in the

An a l y t i c a l Ed i t i o n.

Review papers m ay deal with either methods or instruments.

3. Papers on the evaluation of analytical results or the statistical treatm ent or interpretation of analytical and test data are becoming increasingly im portant.

Such methods can point out human and method errors and provide a very useful means of eliminating un­

trustworthy data or methods. Some papers have

been published in this field in the

more are desired.

4. Papers dealing with principles and theory of analytical chemistry are important, in th at they form the basis for new approaches to analytical chemistry and the better understanding of old, established methods. They are of interest to all our readers, both academic and practical. Such a paper should be a thoughtful discussion of analysis and does not neces­

sarily include experimental work. Very few papers of this kind have been submitted to the

Ed i t i o n,

and some criticism has come from the more

theoretically minded analysts that this is a weakness of the publication. We welcome such papers.

5. General papers on the college training of person­

nel are important, as well as those which deal with the training programs, organization, and operation of analytical laboratories in industry and in research foundations. The function of the research analyst in a well-integrated research program is now receiving greater attention. A successful attack on some re­

search problems is sometimes impossible unless re­

search on methods is worked out in advance, or carried on simultaneously. The analyst on such problems must be of the highest caliber both as a chemist and as an analyst. While these phases of analytical chem­

istry present problems to many hundreds of people, few papers on these subjects appear.

6. Efficient physical equipment and layout are as im portant as properly trained personnel. M any times these subjects are discussed by correspondence be­

tween the heads of analytical laboratories, b u t papers discussing these problems would serve a larger audience.

Floor plans of analytical laboratories have been pub­

lished in the

from time to time, but a critical statem ent of the reasons for the selection of a particular laboratory setup would enhance their value.

7. The application and development of instruments designed for analyses are likely to receive greater a t­

tention from authors. The increase in the importance of this field as envisioned by your editors is indicated by the monthly articles on instrum entation, written by Ralph H. Muller, th a t began to appear in January of this year.

There may be other subjects which our readers would

like to see discussed in the

We

welcome your suggestions.

Optical Methods in Electrophoresis

Principles, A pparatus, Determination of A pparatus Constants, and A p p lica tio n to Refractive Index Measurements

L . G . L O N G S W O R T H

Laboratories, The Rockefeller Institute for Medical Research, New York, N . V .

Th e optical equipm ent developed at The R ockefeller Insti­

tute for the quantitative study of refractive index gradients in solution is described, together with suggestions for its installation and adjustment. This equipm ent, which is based on the Foucault-Toepler schlieren method, also in­

corporates the author’s scanning m odification and the cy lin d rica l lens arrangement of Philpot and Svensson. A l -

T

stitute, for use in the electrophoretic analysis of proteins by the Tiselius moving boundary method (19), has been dupli­

cated in other laboratories and has been made available com­

mercially. (The complete apparatus, in essentially the form described here, is supplied by the K lett Mfg. Co., New Y ork, N. Y.) As a result, over forty installations are now in use both here and abroad. Although based on Tiselius’ adaptation of the Foucault-Toepler schlieren method, the details of the apparatus have been evolved in this laboratory and an adequate description of them, which is given in this paper for the first time, should prove of value to investigators in the field of electrophoresis.

W ith these same workers in mind a description of precise meth­

ods for testing and focusing the equipment and for determining the constants of the apparatus is also included. Not included in this article are descriptions of the electrophoresis process nor of the moving boundary' cell and its accessories, since these have been adequately treated elsewhere (7, 9, 10).

Precise interpretation of the patterns th a t are obtained in the electrophoresis and the diffusion of proteins has been hindered, however, by the lack of adequate data on the refractive indices of solutions of these materials. This is especially true a t 0 , the tem perature a t which proteins are frequently studied. Since the optical equipment described here is well adapted for such meas­

urements on aqueous solutions in general, this application is dis­

cussed.

P R IN C IP L E O F T H E S C H L I E R E N M E T H O D

The essential features of the schlieren method may' be described with the aid of Figure 1.

An image a t P of the point source of light, S, is formed by' a lens, L. The objective, 0 , of a camera is placed ju st to the right of P and is focused on L, thereby forming an image of this lens

• on the screen a t G. ,

Each portion of L is capable, of course, of forming an image ot point S and if this lens is perfect all the images thus formed will superimpose a t P. If, however, a portion of the lens is imperlect, the image formed by this area will not coincide with the other images.

though the chief use of the apparatus is to record the mov­

ing boundary patterns in the electrophoretic analysis of proteins b y the Tiselius method, this application has been adequately discussed elsewhere and is not included here.

The precise measurement of refractive index differences in aqueous solutions represents, however, a recent a p p lica­

tion of the apparatus and is described.

In Figure 1 an exaggerated imperfection, idealized as a tiny prism, is indicated a t A and the image formed by this portion of the lens as being a t Q. Normally this imperfection is not visible in the image of the lens a t G, since it is a property of the camera objective th a t all rays originating in itso b je c t plane are brought to focus a t the conjugate points in the image plane regardless of the portion of the objective through which they pass. I t is as­

sumed, of course, th a t the intervening regions are optically homo­

geneous. If, however, the opaque screen, D. is raised so as to in­

tercept the light forming image Q, while allowing th a t forming image P to pass, th e region of imperfection will become visible a t A ' as a dark area, or shadow, in the otherwise uniformly il­

luminated image of the lens, L. This will be recognized as a simple example of Foucault’s knife-edge test.

Toepler observed th a t if the lens, L, were free from imperfec­

tions the camera could be focused on a plane in front of th a t lens and variations of refractive index in, or near, th a t plane could be made visible as shadows, just as the lens imperfections were rendered visible in F oucault’s test. The shadows he balled schlieren and the method the schlieren method. The lens, L, of Figure 1, is called the schlieren lens, the intercepting screen, D, the schlieren diaphragm, and the camera the schlieren camera. An excellent discussion and bibliography of the schlieren method are given in Schardin’s monograph (13).

219

220 I N D U S T R I A 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. 18, No. 4 The form that the schlieren method takes for the observation

and photography of refractive index gradients th a t occur in moving boundary and diffusion studies is shown diagrammati- cally in Figure 2. In this case gravity ensures th a t the density and, in general, the refractive index are uniform throughout each horizontal layer in the boundary.

The schlieren lens, L, then forms a t K0 in the plane of the schlie- rcn diaphragm, D, an image of the illuminated, horizontal slit, S. The camera lens, 0, is now focused on the cell, C (Figure 2), and forms an image of it on th e screen a t G. If the fluid in the cell is homogeneous this image will bo uniformly illuminated.

Suppose, however, th a t a boundary between, for example, a pro­

tein-bearing solution and a buffer solution is present in the chan­

nel. Such a boundary will consist of a region, B, of finite thick­

ness, in which the concentration and hence the refractive index, n, vary continuously with the height, h, from its constant value in one homogeneous solution to th a t in the other solution. The gradient, dn/dh, of refractive index, which may be abbreviated to n', will thus vary from zero to a maximum, and back to zero.

In Figure 2 the variation of the gradient in the boundary is indicated by the density of the shading. Each layer of solution in this boundary acts, therefore, like a prism and deflects thé light passing through it. If the denser solution underneath has the higher refractive index, as is usually the case, the deflection is downward. Moreover, if a layer is sufficiently thin the gradient may be considered constant in it and the light passing through this layer forms an image of the slit below the normal one a t Ko.

Two such displaced slit images are indicated in Figure 2. The one a t Y„ is formed by the layer of solution a t hm having the maxi­

mum value of dn/dh—i.e., nm'. T h at a t Y i is the superposition of the two images formed by the two layers a t hi and hj for which n ' has identical values. Actually, as is shown in Figure 3 for a typical case, th e displaced slit images formed by all the layers in the boundary combine to give, as

first described by Gouy (4), an in­

teresting p attern of interference in the region from Ko to Y„.

If, now, the upper edge of the schlieren diaphragm D (Figure 2) is raised to level Km the light through the layer a t h„ in the boundary will be intercepted and a dark, narrow band will appear a t the conjugate level, H m, in the image of the channel. On raising this diaphragm further—e.g., to level K,—the light from hi and hj, together w ith th a t from all inter­

vening layers in the boundary, will be intercepted and the dark band in the image of the channel will broaden until the edges of the band are a t the conjugate levels Hi and Hj. This, obviously, can be continued until the un­

deflected rays a t K0 have been in­

tercepted and the entire image becomes dark.

W ith a single boundary in the channel a series of fourteen photographs was taken, with the schlieren diaphragm raised a

fixed distance between each exposure, and is shown in Figure 4, a.

The progressive broadening of the schlieren band is apparent.

If an exposure is made when the displacement of the diaphragm from the normal slit image is Y , — K0, for example, th e edges of the band in th a t photograph are then conjugate to the levels in the channel a t which the refractive index gradient has a value proportional to Kj — K0. The proportionality factor is (21), to a very close approximation, the product a X b, in which a is the dimension of the channel parallel to the optic axis and b is the optical dis­

tance from the center of the channel to the schlieren diaphragm

K - K0 = AK = a b n ' (1) S C H L IE R E N S C A N N I N G M E T H O D

In the schlieren scanning procedure (8) the stepwise recording shown in Figure 4, a, is made continuous.

The image of the cell a t G (Figure 2) is masked by a vertical slit of 0.2-mm. w idth and a photographic plate is moved in the direction, N, of th e arrow a t a constant rate across this slit. Actuated by the same mechanism, dia­

phragm D is given a steady movement upward.

The resulting photographic positive for the boundary of Figure 4, a, is shown in Figure 4,6, and is called the' boundary pattern. I t null be noted th a t the schlieren bands of Figure 4, a, correspond to narrow vortical sec­

tions in the complete pattern. For purposes of publication it is the almost universal practice to turn the pattern through 90° as shown in Figure 4, c. If more than one boundary is present in the channel each appears as a separate peak in th e complete pattern.

■

Figure 3. Interference Patterns at Schlieren

Diaphragm

Figure 4. Schlieren Band and Scanning Photographs of a Single Boundary

The outline of the shaded area in Figure 4, c, is, therefore, a plot of the refractive index gradient in a thin layer of solution in the channel as ordinate against the height of the layer as ab -‘

scissa. If E is the enlargement factor for the camera, the scale of abscissas for this plot is Eh, which wall be designated as H.

The ordinate scale is abMn', designated as N, in which M is the ratio of the rates a t which th e plate and diaphragm move in the scanning process. The vertical line a t Ho in Figure 4, c, is due to a graduation on the cell and is taken as the origin of abscissas.

The origin of ordinates is the horizontal line a t No joining those portions of the pattern outline th a t correspond to layers in the channel in which the solution is homogeneous. This is the “ base line” of the pattern. In the ideal case this line is straight and horizontal. In practice, however, it is distorted slightly by im­

perfections in the lenses and in the cell and therm ostat windows.

Allowance for these distortions is made with the aid of a scanning photograph of the cell when it contains a homogeneous solution.

C Y L I N D R I C A L L E N S M E T H O D

In the scanning method described above th e complete pattern is not visible in the focus of the camera b u t only on th e de­

veloped photographic plate. I t is convenient, however, to bo able to observe the pattern directly on the ground glass. The cylindrical lens method (11,16,17) makes this possible and repre­

sents a useful addition to the schlieren camera.

In this method th e schlieren diaphragm takes the form of a narrow slit, I (Figure 5), th a t is inclined to the vertical a t an angle of, say, 45°. Moreover, a cylindrical lens, with its axis vertical, is interposed a t C and is focused on the inclined slit and on the screen a t G. Otherwise, the arrangement is as shown in