INDUSTRIAL A N D ENGINEERING CHEMISTRY
A N A L Y T I C A L E D I T I O N '%
H A R R IS O N E. H O W E , E D IT O R m IS S U E D D E C E M B E R 16, 1940 » V O L . 12, NO. 12 ♦ C O N S E C U T IV E NO. 24
De t e r m i n a t i o n o p Bi o c h e m i c a l Ox y g e n De m a n d a n d Di s s o l v e d Ox y g e n o p Ri v e r Mu d Su s p e n s i o n s . .
C. C. Ruchhoft and W. Allan Moore 711
Co l o r i m e t r i c An a l y s i s o f Tw o- Co m p o n e n t Co l o r S y s t e m ...Harold W. Knudson,
Villiers W. Meloche, and Chancey Juday 715
De t e r m i n a t i o n o p Su l f u r i n Co a l a n d Co k e . . . .
H. L. Brunjes and M. J. Manning 718
Re c o v e r y o f Fu r f u r a l f r o m Aq u e o u s So l u t i o n s . .
Floyd Trimble and A. P. Dunlop 721
De t e r m i n a t i o n o f Me t h i o n i n e i n Ce r t a i n Mi x t u r e s
Joseph J. Kolb and Gerrit Toennies 723
D e t e r m i n a t i o n o f O r g a n i c S u l f u r i n C o m b u s t i b l e G a s ...F. M. Rogers and R. F. Baldaste 724
De t e r m i n a t i o n o f Ca r o t e n e i n Pl a n t Ma t e r i a l . .
L. A. Moore 726
D e t e r m i n a t i o n o f G l y c e r o l b y O x i d a t i o n w i t h C e r i c S u l f a t e i n F e r m e n t a t i o n M e d i a C o n t a i n i n g D e x t r o s e ...E. I. FuLmer,
R. J. Hickey, and L. A. Underkoflcr 729
P h o t o m e t r i c D e t e r m i n a t i o n o f P o t a s s i u m w i t h D i p i c r y l a m i n e ...Elias Amdur 731
I o d i n e i n T h y r o i d . . R. S . Burnett and R. F. Warkow 734
El e c t r o l y t i c De t e r m i n a t i o n o f Co p p e r i n St e e l . .
H. A. Frediani and C. H. Hale 736
I d e n t i f i c a t i o n o f P r i m a r y A l i p h a t i c A m i d e s a s
O x a l a t e s . . . C. A. MacKenzie and W. T. Rawles 737
S t u d i e s o f O r g a n i c R e a g e n t s a n d M e t h o d s I n v o l v i n g
T h e i r U s e . . N. Howell Furman and John F. Flagg 738
De t e r m i n a t i o n o f Go s s y p o l i n Cr u d e Co t t o n s e e d Oi l
H. D. Royce, J. R. Harrison, and Parker D. Deans 741
R e c t i f i c a t i o n C o l u m n f o r a C h e m i c a l E n g i n e e r i n g
L a b o r a t o r y . John R. Huffman and Robert E. Treybal 745
Ac e t o n e- Et h e r Mi x t u r e s f o r Dr y i n g Gl a s s w a r e. .
Aaron E. Markham 748
S u p e r s o n i c O s c i l l a t o r ...Bernard H. Porter 748
Us e o f Co n d e n s e r t o Re d u c e Ga l v a n o m e t e r Os c i l l a t i o n s i n Po l a r o g r a p i i i c Me a s u r e m e n t s w i t h Pa r t i c u l a r Ap p l i c a t i o n t o Co m p e n s a t i o n Me t h o d o f Me a s u r i n g Sm a l l Di f f u s i o n Cu r r e n t s . . . .
James J. Lingane and Herbert Kerlinger 750
Hi g h- Ou t p u t El e c t r i c Fl a s k He a t e r ...
Harold A. Krantz and Ralph W. Hufferd 752
A c c u r a t e M e a s u r e m e n t o f X - R a y D i f f r a c t i o n F i l m s
Harold P. Klug 753
Ce n t r i f u g e Co o l i n g Un i t...
H. L. Wunderly and L. S. Smelo 754
L a b o r a t o r y - S i z e L e a f - T y p e P r e s s u r e F i l t e r . . . .
T. F. Clark, N. Porges, and S. I. Aronovsky 755
E l e c t r o n i c R e l a y . . C . E. Rudy, Jr., and Paul Fugassi 757
Mi c r o c h e m i s t r y:
De t e r m i n a t i o n o f La c t i c Ac i d i n Bl o o d...
Samuel Elgart and J. S. Harris 758
M o r i n R e a c t i o n f o r B e r y l l i u m . . E. B. Sandell 762
Sy s t e m a t i c Qu a l i t a t i v e Or g a n i c Mi c r o a n a l y s i s .
Herbert K. Alber 764
De t e r m i n a t i o n o f M e r c u r y i n Ur i n e ...
Donald M. Hubbard 768
T i t r a t i o n o f A m m o n i a i n P r e s e n c e o f B o r i c A c i d i n M a c r o - , S e m i m i c r o - , a n d M i c r o - K j e l d a h l P r o c e d u r e s , U s i n g M e t h y l R e d I n d i c a t o r a n d C o l o r - M a t c h i n g E n d P o i n t . . . .E. C. Wagner 771
Mi c r o a p p a r a t u sf o r Fr a c t i o n a l Re c r y s t a l l i z a t i o n
• Lyman C. Craig 773
N e w O x i d a t i o n - R e d u c t i o n R e a c t i o n C a t a l y z e d b y
I o d i n e . . . . David Hart and Robert Meyrowitz 774
Ga s o m e t e r f o r Mi c r o- Du m a s De t e r m i n a t i o n s . .
Joseph G. Sandza and Joseph F. Alicino 776
A d a p t i n g P o l a r i z i n g M i c r o s c o p e f o r U s e a s P o l a r i m e t e r ...Alexander Marion 777
Mo d e r n La b o r a t o r i e s:
I I o u d r y L a b o r a t o r i e s o f t h e C a t a l y t i c D e v e l o p m e n t C o m p a n y ... H. P. Broom 778
Co r r e s p o n d e n c e:
Ne w De v e l o p m e n t i n Th e r m i o n i c Re l a y s . . . .
Lee Nutting; Walter Saeman 714
J a c k e t e d R e c e i v e r f o r V a c u u m D i s t i l l a t i o n . . . 744
To x i c i t y o f Ar o m a t i c s...
G. R. Gilbert and R. E. Tannich 767
A u t h o r I n d e x ...781
S u b j e c t I n d e x ... 786
T h e A m e r ic a n C h e m ic a l S o c ie t y assu m es n o r e s p o n s ib ilit y fo r 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 t r ib u to r s t o its p u b lic a tio n s .
2 3 ,0 0 0 co p ie s o f th is issu e p r in te d . C o p y r ig h t 1940 b y A m e r ic a n C h e m ic a l S o c ie t y .
Publication Office:
E d i t o r i a l O f f i c e : R o o m 7 0 6 , M i l l s B u i l d i n g , W a s h i n g t o n , D . C . T e l e p h o n e : N a t i o n a l 0 8 4 8 . C a b l e : J i e c l i e m ( W a s h i n g t o n )
P u b lis h e d b y th e A m e r ic a n C h e m ic a l S o c ie t y , P u b lic a t io n O ffice , 2 0 th &
N o r t h a m p to n S ts., E a s to n , P e n n a . E n te r e d as s e c o n d -c la s s m a tte r a t th e P o s t O ffice at E a s to n , P e n n a ., u n d e r th e A c t o f M a r c h 3, 1879, as 24 tim e s a y e a r . In d u s tr ia l E d it i o n m o n t h ly o n th e 1 st; A n a ly tic a l E d it io n m o n t h ly o n th e 1 5th . A c c e p t a n c e fo r m a ilin g a t s p e cia l ra te o f p o s ta g e p r o v id e d fo r in S e c tio n 1103, A c t o f O c t o b e r 3, 1917, a u th o r iz e d J u ly 13, 1918.
A n n u a l s u b s c r ip tio n ra te, In d u s t r i a l Ed i t i o na n d An a l y t i c a l Ed i t i o n s o ld o n ly as a u n it, S4.00. F o r e ig n p o s ta g e t o c o u n tr ie s n o t in th e P a n
E a H to n , P e n n a .
A d v e r t i s i n g D e p a r t m e n t : 332 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 : B r y a n t 9 -4 4 3 0
A m e r ic a n U n io n , $ 2 .2 5 ; C a n a d ia n p o s ta g e , $ 0 .7 5 . S in g le c o p ie s : In d u s tria l E d it io n , $ 0 .7 5 ; A n a ly ti c a l E d it io n , $ 0 .5 0 . S p e c ia l rates t o m e m b e rs.
N o c la im s c a n b e a llo w e d f o r co p ie s o f jo u r n a ls lo s t in th e m a ils unless s u ch c la im s a re r e c e iv e d w ith in 6 0 d a y s o f th e d a te o f issu e, a n d n o cla im s w ill b e a llo w e d f o r issu es lo s t as a resu lt o f in s u fficie n t n o t ic e o f c h a n g e o f a d d re ss. ( T e n d a y s ’ a d v a n c e n o tice r e q u ir e d .) “ M is s in g fr o m file s ” c a n n o t b e a c c e p t e d as th e re a s o n f o r h o n o r in g a c la im . C h a rle s L . P a rson s, B u sin ess M a n a g e r , 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. 12, NO. 12
FIXTURES
T W O MOST W IDELY
ACCEPTER F ü R » ACES ł l C ‘ „ b o b C O M B V S T ' O «
T he N o. 1 a rro w points to our FH -3 0 3 -A w h o s e c a s e diam eter used to be 5 " a n d is n o w 7 " . The in creased in su latio n results in a c a se tem perature that is 1 2 0 ° F.
cooler. T he holding w a tta g e h a s been reduced 18%. T h e tim e to heat from 8 0 ° to 2 0 0 0 ° F. h as been lo w ere d 50 % an d is n o w 6 3 m inutes. Th e price fo rth e com plete jo b , in clud in g transform er and rheostat, is le ss than 9%
m ore than fo rm e rly. T h e fu rn ace is ce rta in ly w orth that little extra cost. . . . This F H -3 0 3 -A stands hard u se. Note b e lo w its h e a v y
No. 2 points to the FD-303-A, which also has a 7 n case. It operates on A .C . or D .C. and does not require a transformer. Rheostatic temperature control.
Safe maximum operating temperature is 1800° F.
heating unit, m ade of 7 G a u g e C hrom el A — v e ry hard to w e a r out, an d v e ry e a s y to ren e w . The fu rn ace operates o n ly on A .C . through a sm all transform er. The top sa fe tem perature is 2 0 0 0 ° F.
an d is controlled by a rheostat.
If you need a com bustion fu rn ace that m ust stand re a lly hard se rv ice, yo u need this H oskin s FH- 3 0 3 - A . Write to us or yo u r d e ale r for quotation. . . . H oskin s M an u facturing C o m p a n y , Detroit, M ich.
H O S K I N S P R O D U C T S
E L E C T R IC H E A T T R E A T IN G F U R N A C E S H E A T IN G E L E M E N T A L L O Y S T H E R M O C O U P L E A N D LEAD W IRE PYROMETERS W ELD IN G W IRE HEAT RESISTAN T C ASTIN G S • • ENAM ELING SPARK PLUG ELECTRODE W IRE SPECIA L A LLO YS OF N ICKEL PROTECTION TUBES
DECEMBER 15, 1940 ANALYTICAL EDITION 5
The Fifth Edition of
Is N ow Available
An Encyclopedia of Chemicals and Drugs for the Chemist, Pharmacist, Physician, Dentist & Veterinarian.
S P E C I A L P R I C E OF $ 3.00
(P rice in Canada, $3.50)• 1,060 pages—nearly twice the num
ber o f the previous edition.
• Contains more than 5,900 descrip
tions o f individual substances.
• An important new feature is the sec
tion, “ Chemical, Clinico-Chemical Reactions, Tests and Reagents by the Author’s Name” which includes more than 4,500 numbered Tests, Reac
tions and Reagents.
• In the section on “ Coal-Tar Colors for Use in Foods, Drugs and Cosmet
ics,” 113 colors are described.
• The section on “ Indicators” covers 126 indicators, and the section on
“ Minerals” embodies the description, formulas, and percentage composi
tion o f 187 minerals.
• Another new section contains formu
las for the preparation o f Culture Media, Fixatives, and Staining Solu
tions, comprising a total o f 212 for
mulas and methods o f preparation.
9 Also Useful Tables, Antidotes for Poisons, and Literature References.
Printed in clear type on English finish paper, bound in black semi-flexible imi
tation leather covers and stamped in gold.
What Trade and Professional Journals Say about The Merck Index
“ T h e la b ors o f th e c o m p ile r s*** m u s t h a v e b e e n g r e a t in p r e p a r in g so c o m p r e h en s iv e a n d e s s e n tia lly u s e fu l a volume.**
— Journal o f the American Chemical Society.
liO n e o f th e c la im s f o r th is r e f e r e n c e is its sp e c ia l va lu e to th e s c ie n c e w o rk er i n te r e s te d in in fo r m a tio n n o t c o m m o n ly fo u n d in p u r e l y c h e m ic a l lite r a tu r e , e s p e c ia lly m a te r ia l w ith w h ich p h a r m a cists, p h y s ic ia n s , d e n tis t s a n d v e te r in a rians are con cern ed .*’— CanadianChemistry.
ilT his fifth ed itio n o f T h e M e r c k In d e x is
*b ig g er a n d b etter* th a n ev er b e fo r e . I t c o n ta in s a b o u t tw ic e th e n u m b e r o f p a g e s th a n th e p r e v io u s e d itio n a n d m u c h m o r e th a n d o u b le th e in form a tion .**
— Oil, Paint and Drug Reporter.
‘ ‘ W e lik e th e 1940 M e r c k In d ex. W e r e c o m m e n d it.**— The Chemical Bulletin.
“ A t th e c o s t p r ic e o f th r e e d ollars fo r
w h ich i t is o ffer ed , n o s c i e n tis t s h o u ld b e w i th o u t T h e M e r c k In d ex . T h e b o o k sh o u ld b e o f in e s t im a b le v a lu e to r e sea rch w o r k e r s w h o d esire to e s ta b lis h p r io r in fo r m a tio n o n th e s u b je c t w h ic h
t h e y a re in v e s tig a tin g .**— The Catalyst.
“ O n e o f th e b e s t c o m p l im e n t s ev e r p a id to th is v a lu a b le w o r k w as in th e r o u t i n e a d v ice o f th e la te D ea n C h arles H . L a W a ll.
H e w o u ld a lw ays to h is in q u ir in g a ssis
ta n ts s a y : ‘ L o o k i t up, first o f a ll, in T h e M e r c k In d e x — i f i t is n ’ t th e r e , l o o k e v e r y w h e r e else.* **
— American Journal o f Pharmacy.
“ T h is va lu a b le p u b lic a tio n , in e x p e n s iv e b e c a u s e i t is p u b lis h e d o n a n o n - p r o f it basis, c o n ta in s a m a ss o f h ig h ly u s e fu l a n d a c c u r a te in fo r m a tio n . I t w ill b e o f u se to p h y s ic ia n , d e n tis t , v eterin a ria n , a n d to th e la b o r a to r y w o r k e r as w e ll as th e c lin ic ia n .**— The American Journal o f the Medical Sciences.
MERCK & CO. Inc. . RAH W AY, N. J.
In Canada: MERCK & CO. Lid • MONTREAL & TORONTO
This order form w ill bring y o u The M erck Index p ro m p tly . M ail it today.
Professional O rd er Form 21-12
M E R C K & C O . I n c ., R a h w a y , N . J.
P le a s e se n d m e o n e c o p y o f T H E M E R C K I N D E X ( F i ft h E d it i o n ) a t th e s p e cia l p r ice o f $ 3 .0 0 . ($ 3 .5 0 in C a n a d a ).
□ C h e ck , o r m o n e y o r d e r , is e n c lo s e d .* □ S e n d b o o k C . O . D .
* I f y o u d esire t o se n d r e m it t a n c e in s te a d o f r e c e iv in g th e b o o k C . O . D . e n clo se th is c o u p o n a n d y o u r c h e c k o r m o n e y o r d e r fo r $ 3 .0 0 in a sea led e n v e lo p e a n d th e b o o k w ill b e m a ile d p r e p a id .
Name.
(P le a se in d ic a te title , i f a n y ) S t r e e t .
. State.
6 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 12, NO. 12
The n e w Sobers V e r t i c o l C o m bustion Fu rn ace s h o w in g e le v a to r in lo a d in g
position
V e rtic a l COMBUSTION FURNACE
O u
HEVI DUTY
The S o b e r s V e r tic a l C om bustion F u r n a c e is d e s ig n e d f o r e a s e , sp eed and econom y in the d e ter
mination of carbon in iron and steel b y the direct combustion method. If sp eed and accu racy in carbon d e terminations a re im portant to you see yo u r la b o ra to ry supply d e a le r . . . or w rite for Bulletin HD1040.
U T Y E L E C T R I C C O M P A N Y
HEAT TREATING FURNACES E L E C T R I C E X C L U S I V E L Y
M I L W A U K E E , W I S C O N S I N
DECEMBER 15, 1940 ANALYTICAL EDITION 7
SODIUM OXALATE P rim ary S tan dard
NijCjO«
anALYTICAL REAGENT p o i s o n
wckrodt Chemicalv
?? »«owhial r-LAtmr*1*
PRECISION ^
in the L A B O R A T O R Y
A ccurately m easuring laboratory app aratu s is of little value in analytical procedure unless th e chemicals employed are free from im purities giving rise to erroneous results. M allinckrodt A nalytical R eagents— each scrupulously refined to m eet predeterm ined sta n d ards of p u rity — are especially designed to facilitate analytical p re
cision. Chem ists can depend upon M allinckrodt A. R. Chemicals because th ey conform to A. C. S. specifications.
Send fo r new catalogue o f analytical reagents and other chemi
cals for laboratory use. It contains descriptions o f chemi
cals suitable for every type o f analytical work . . . gravi
metric, gasometric, colorimetric or titrimetric.
M A L L I N C K R O D T C H E M I C A L W O R K S
Chicago • Philadelphia • New York
St. Louis
8 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 12, NO. 12
December
BAKER & ADAMSON
« - s a ™ PRODUCTS ) USERS C
C H E M I C A L
IHE CHEM ICALS l a b o r a t o r y . REAGENTS A
the follow ing
w h e r e v e r C h e m i c a l s
j only the
i m p r o v e , R e a g e n t <
c u s t o m e r s
d o m e s t i c p
; p r e v i o u s l y u n d e r t a k e n <
w h i c h w e r e
We have
c h e m i c a l s
d e v e l o p - n i c a l s o f
B
a k e r&
o, g e n e r a lc h e m ic a l Division
DECEMBER 15, 1940 ANALYTICAL EDITION 9
NEW IN T E R N A T IO N A L
Size 3, FS Centrifuge 4 L itre H ea d
Here is the answer to present day demands for greater centrifuge capacity in your laboratory. The new 4 Liter Head permits large scale separation for blood plasma, serums, vaccines and many other substances.
4 L IT R E W I N D S H I E L D E D H E A D
DESIGNED FOR 1,000 ML. BOTTLES The more recent demand for the 1,000 ml.
bottles, needed for large scale centrifugation of plasma for blood banks and many other biological products, has led to the develop
ment o f tills 4 Litre Head as an alternate for the 3 Litre Head, which accommodates the 500 ml. bottles.
The new head (Cat. 261) accommodates 4 slotted duralumin cups (Cat. 389) for the 1,000 ml. glass bottles. A spun aluminum bowl encloses the head to reduce wind re
sistance and thus minimize the heating of contents.
INTERNATIONAL
SIZE 3, MODEL FS CENTRIFUGE
Popular in Biological and Industrial Laboratories, the International Size 3, M odel FS Centrifuge is shown here equipped for 3 Litres with a 6-place windshielded head (Cat. 258), accommodating the 500 ml. glass bottles. The all-steel boiler plate guard affords adequate protection and a T A C H O M E T E R shows at a glance the speed at any setting o f the speed controller.
SPECIFICATIONS:
• Large Capacity (6-500 ml. bottles or 4-1,000 ml. bottles)
• Speed with 3 Litre Head (3,000 r.p.m. or 2,850 X gravity)
• Speed with 4 Litre Head (2,400 r.p.m. or 1,850 X gravity)
• Forged Duralumin Cups
• Mounted on Rubber Vibration Dampeners
• Vertical M otor Drive
• Flexibly Mounted Shaft (for bet
ter running balance)
T h e re is an In te rn a tio n a l fo r a n y jo b
IN TER N A TIO N A L EQUIPM ENT CO.
Makers of Fine Centrifuges B O S T O N , M A S S .
352 W ESTER N A V E N U E
10 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 12, NO. 12
S E R F A S S
E L E C T R O N R A Y T I T R A T I O N A S S E M B L Y
F O R T H E D E T E R M IN A T IO N O F E N D P O IN T S IN G E N E R A L O X I D A T I O N - R E D U C T IO N R E A C T IO N S
E LE C TR O N R A Y T IT R A T IO N A S S E M B L Y , Serfass. Consisting of an electrical control unit with an electron ray tube (magic eye) mounted in external holder and A .H .T. Co. Titration Stand with accessory equip ment including platinum and tungsten electrodes.
The outfit operates directly from either a.c. or d.c. supply systems on a simple elec
tronic circuit designed by Dr. Earl J. Serfass, of Lehigh University. See Industrial and Engineering Chemistry, Anal. Ed., Vol. 12, No. 9 (September 15th, 19Jt0), p. 536. The amplified potential differences originating between the electrode-solution interface are transmitted to the electron ray tube which indicates endpoints instantaneously by a change in the size of the wedge-shaped shadow which appears on the
circular fluorescent target within the tube. The endpoint occurs when the largest permanent change in shadow angle takes place per drop of titrant added.
The control unit consists of a compact vacuum tube voltmeter with voltage regulator and connections for power supply, electron ray tube, electrodes and stirring motor. On the panel are dials for variation of sensitivity and control of the ray posi
tion and switches for connection with power supply and stirring motor and for control of the polarizing current. The electron ray tube is mounted in a separate housing with adjustable clamp for attach
ment to the vertical rod of a support stand for con
venient observation of endpoints as indicated by the opening and closing of the “ eye.”
The outfit utilizes the self-polarizing platinum- tungsten electrode system and is suitable for use with platinum-nickel, calomel-platinum or polarized platinum-platinum electrode systems, but is not adapted for titrations requiring the glass electrode.
P a rticu la rly suita ble fo r:
T h e d ir e ct d e te r m in a tio n o f c h r o m iu m a n d v a n a d iu m in s te e l.
T h e d e te r m in a tio n o f c h r o m iu m in c h r o m e ta n n e d 4 93 7.
le a th e r a n d in c h r o m e ta n n in g liq u o rs .
G e n e r a l p o te n tio m e tr ic titra tio n s in v o lv in g p o ta s s iu m d ic h r o m a te , io d in e , p e r m a n g a n a te , e e r ie s u lp h a te , fe r r o u s su lp h a te , s o d iu m t h io s u l- p h a te a n d fe r r o c y a n id e .
L im ite d a p p lica tio n s to a c i d -b a s e a n d p r e c ip ita tio n titra tio n s , b u t n o t a d a p te d f o r p H d e te r m in a tio n s .
A d v a n ta g e s:
S im p lic ity o f o p e r a tio n .
T u rb id ity a n d c o lo r d o n o t a ffe c t a c c u r a c y .
T h e u s u a l d e lic a te in d ica tin g m e t e r is r e p la c e d b y th e e le c t r o n ra y t u b e w h ic h in d ic a te s c o n t in u o u s ly w ith o u t th e a n n o y a n c e o f k e y ta p p in g . L in e o p e r a tio n e lim in a te s th e in h e r e n t d is a d v a n ta g e s o f b a tte r y o p e ra tio n .
A v o lta g e r e g u la to r s ta b iliz e s th e in s tru m e n t a g a in s t a .c . lin e flu c tu a tio n s .
S e n s itiv ity is c o n tin u o u s ly v a r ia b le , w ith fu ll 1 0 0 ° s h a d o w a n g le in th e “ m a g ic e y e ,” f r o m 50 m illiv o lts u p w a rd . T h e c o n tr o l u nit su p p lie s p o la riz in g cu rre n t w h e n r e q u ir e d f o r p o la r iz in g m o n o - m e t a l l ic e l e c t r o d e s .
T h e e le ctr ic a l u n it is p la c e d to o n e s id e o f th e titra tio n s ta n d a n d is t h e r e fo r e n o t s u b j e c t t o c o r r o s io n f r o m th e s a m p le .
4937. Electron Ray Titration Assembly, Serfass, as above described, complete assembly as shown in illustration, consisting of control unit with electron ray tube in separate housing with adjustable clamp for attachment to support rod, titration stand complete with base and swinging shelf of Coors porcelain, paired burettes, clamps, platinum and tungsten electrodes with holder, and stirring apparatus with motor for 110 volts, 60 cycles, single phase a.c. With detailed directions for use including step by step procedures for typical titrations and preparation of standard solutions...83.95 4937-F. Control Unit, Serfass, only, as included in above outfit, with electron ray tube in separate cylindrical housing with adjustable clamp for attachment to support rod. For 110 volts, 25 to 60 cycles, a.c... 40.00
N O T E — C o n tr o l U n it ca n b e s u p p lie d f o r u se o n 2 2 0 v o lt s a. c. a n d f o r 110 o r 2 2 0 v o lt s a . c . / d . c . P ric e s o n re q u e st.
M o r e d e ta ile d inform ation sen t upon req u est.
A R T H U R H. T H O M A S C O M P A N Y
R E T A I L — W H O L E S A L E — E X P O R T
LA B O R A TO R Y A P PA R A TU S A N D R EA G EN TS
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 IA , U . S . A.
Cable Address, “ Balance,” Philadelphia
INDUSTRIAL a n d ENGINEERING CHEMISTRY
A N A L Y T I C A L E D I T I O N
P U B L I S H E D B Y T H E A M E R I C A N C H E M I C A L S O C I E T Y • H A R R I S O N E. H O W E , E D I T O R
Determination of Biochemical Oxygen Demand and Dissolved Oxygen of River Mud
Suspensions
C . C . R U C H H O F T a n d W . A L L A N iM O O R E
U . S . P u b l i c H e a lt h S e r v ic e , S t r e a m P o l l u t i o n I n v e s t ig a t io n s S t a t i o n , C i n c i n n a t i , O h io
I
N STUDYING pollution contributed by organic matter deposited on the bottoms of flowing streams, it is frequently necessary to determine dissolved oxygen in suspen
sions of river muds. Dissolved oxygen in such suspensions has been determined in the past by either the short or Rideal- Stewart modifications of the Winkler method. Stephenson (3?) has reported recently that the test for dissolved oxygen absorbed (B. 0 . D. test) is unreliable when applied to turbid unfiltered waters. When the initial dissolved oxygen content of a mud suspension is calculated from the dissolved oxygen of the dilution water (the mud being septic) it has frequently been observed that this calculated initial value is higher than that found by these analytical procedures. The above ap
parent oxygen loss is similar to the immediate loss of oxygen that is observed when septic sewage, effluent, or stream water is diluted with water of a known dissolved oxygen content.
These immediate oxygen losses have been referred to as the immediate or chemical oxygen demand of the material under observation.
The present study of mud suspensions has shown that this so-called immediate oxygen demand is not a true measure of the chemical demand but is largely an apparent oxygen loss due to the failure of the analytical methods employed.
Improved analytical procedures are proposed which give a better approximation of the true dissolved oxygen content under the adverse conditions met in the examination of mud suspensions. The time required under aerobic conditions to eliminate the interfering substances has been investigated, the effect on the biochemical oxygen demand of keeping the solids in suspension throughout the incubation period has been studied, and a procedure for determining the true bio
chemical oxygen demand of these muds is outlined.
Method of Study
The mud samples used in this study, which were septic and viscous, containing from 38 to 68 per cent solids, of which 6.07 to 10.1 per cent were volatile matter, were obtained from various points on the Scioto and Ohio Rivers. One-quarter strength Formula C (5) dilution water previously stored for 5 days at 20° C. was used in making all dilutions. The various dilutions were made by introducing the appropriate amount of the sample under the surface of the dilution water, mixing with as little agitation as possible, and siphoning (with continued stirring) into the appropriate bottles. All dissolved oxygen determina
tions were made in triplicate. The pH determinations were
made electrometrically employing the glass electrode, and stand
ard methods (1) were followed in all other determinations.
Analytical Data
The dissolved oxygen content found by the Rideal-Stewart modification of the Winkler method in a series of suspensions of one sample of Scioto River mud indicated a so-called im
mediate chemical demand of about 1000 p. p. m. This value is typical of mud samples from this portion of the river.
In another experiment the mud was suspended in dilution water as described and the dissolved oxygen was determined immediately afterward by four different procedures. The short Winkler and alkaline hypochlorite methods were applied to the untreated suspension and the short Winkler method was also applied to centrifuged and flocculated portions of the sample. The two latter modifications were carried out as follows:
Four centrifuge bottles were completely filled with suspensions, stoppered, and centrifuged at about 2000 r. p. m. for 5 minutes, after which the supernatant was siphoned into three 300-ml.
dissolved oxygen bottles and the short Winkler procedure ap
plied. To the suspension filling a 1-liter bottle (capacity of about 1150 ml.) 10 ml. of a 10 per cent alum solution were added, followed by 1 to 2 ml. of concentrated ammonium hydroxide, the stopper was inserted, and the contents were mixed by twirling for about a minute. After allowing the “ alum floe” to settle for 10 minutes, the clear supernatant was siphoned into three dis
solved oxygen bottles and the short Winkler procedure applied.
In removing the suspended solids by either centrifuging or by flocculation, it had been found that there was no atmospheric oxygen pickup during these manipulations even at oxygen con
centrations as low as 1.5 p. p. m., providing the usual precautions were taken.
The results obtained in this experiment are shown in Table I. The data indicate that the initial dissolved oxygen re
sults obtained with the short Winkler method were from 8.47 to 74.7 per cent lower than the calculated initial, depending upon the dilution examined. With the alkaline hypochlorite method the results obtained were from 5.84 to 52.8 per cent lower than the calculated initial. When the suspended solids were removed by centrifuging, the initial dissolved oxygen results were only from 1.26 to 15.7 per cent lower than the calculated initial for the different dilutions. Finally, with the flocculated portion the initial results checked with the calculated in the highest dilution and were only from 711
712 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 12, NO. 12
Ta b l e I . Im m e d i a t e Di s s o l v e d Ox y g e n' Da t a o n Sc i o t o Ri v e r Mu d Su s p e n s i o n s
D ilu t io n o f
C a lc u la te d in itia l
--- Diss S h o r t W in k le r
solved O x y g e n --- — A lk a lin e C e n tr i- h y p o - fu g e d c h lo r it e p o r t io n
F lo c c u la te d .--- p o r t io n
• Im m ediate A p p a re n t- O x y g e n D e p le t io n
<--- I m m e d ia t e A p p a r e n t O x y g e n D e p le t i o n ---
^ ^ y in n ^ ^ v i nn é “ v i nn A ~~ ^ v
M u d A B C D E A - B A — C A - D A - E A A A ' ' A
P . p . in. P . p. m. P . p . m. P . p . in. P . p . in. P . p . in., P . p . m . P . p . m. P . p . m . % % % %
1 / 2 5 0 7 . 8 8 1 .9 9 3 . 7 2 6 .6 4 6 . 7 7 5 .8 9 4 . 1 6 1 . 2 4 1 . 1 1 7 4 . 7 5 2 . 8 1 5 .7 1 4 .1
1 /5 0 0 8 . 7 6 6 .2 9 7 . 0 4 8 . 0 6 8 . 0 2 2 . 4 7 1.7 2 0 . 7 0 0 . 7 4 2 8 . 2 1 9 .6 7 . 9 9 8 . 4 4
1 / 1 0 0 0 8 . 7 2 6 .5 7 7 .5 1 7 .9 9 8 . 2 1 2 . 1 5 1 .2 1 0 . 7 3 0 .5 1 2 4 . 6 1 3 .9 8 . 3 7 5 . 8 4
1 / 2 0 0 0 8 . 7 3 7 . 6 5 7 . 7 7 8 . 3 0 8 . 3 5 1 .0 8 0 . 9 6 0 . 4 3 0 . 3 8 1 2 .4 1 1 .0 4 . 7 5 4 . 3 5
1 /4 0 0 0 8 . 7 3 7 .9 9 8 . 2 2 8 . 6 2 8 . 7 3 0 . 7 4 0 . 5 1 0 . 1 1 0 . 0 0 8 . 4 7 5 . 8 4 1 .2 6 0 . 0 0
Ta b l e I I . St e p s i n An a l y t i c a l Pr o c e d u r e s
(In te r fe r e n c e w ith d is s o lv e d o x y g e n d e te r m in a tio n o c c u r s d u r in g c o n t a c t o f re a g e n ts w ith r iv e r m u d su sp en sion s)
A lk a lin iz a tio n C o m p le t e P r e lim in a r y a n d F in a l M e t h o d P r o c e d u r e A c i d T r e a t m e n t A c id ific a t io n R id c a l-S t e w a r t
A z id e m o d ific a tio n
W in k le r S h o r t W in k le r
1.02 1 .4 1
0 . 9 3 0 . 7 0 0.79*>
0.88 1 .1 4
A lk a lin iz a tio n 0 . 1 6 Ó.’ Ó9&
0 . 1 4 0 . 2 7 F in a l A c id ific a t io n
0 . 7 7 0 . 5 2 ° 0 . 8 9 c 0.92<*
1 .0 3 *
° 0 .5 -m in u t e a c id c o n t a c t b e fo r e titr a tio n . b 5 -m in u te p e r io d o f a lk a lin iz a tio n . c 2- m in u t e a c id c o n t a c t b e fo r e t it r a t io n . d 5 -m in u te a c id c o n t a c t b e f o r e t it r a t io n .
* 1 0-m in u t e a c id c o n t a c t b e f o r e t it r a t io n .
4.35 to 14.1 per cent lower than the calculated in the other four dilutions.
As the mud suspensions were in contact longer in the centri
fuged and flocculated portions of these suspensions than in the portions treated immediately by the short Winkler method, lower dissolved oxygen values would be expected in D and E than in A if the losses were true oxygen demands.
From the results obtained it may be inferred that a reaction occurs between the suspension and some or all of the reagents of the Winkler or Rideal-Stewart procedures during the time of contact between the two, thus resulting in lower iodine titers. When the suspended matter was largely removed by centrifuging or flocculation, the larger portion of the inter
fering materials was removed and the dissolved oxygen results approached the calculated initial values. The ex
periment indicated that the immediate oxygen losses ob
tained by the ordinary Winkler procedure, Rideal-Stewart, azide, short, or alkaline hypochlorite modifications are due to interference with the analytical procedures and are not true oxygen demands.
Another series of experiments was performed to determine in which step or steps of the analytical procedures the inter
ference occurred.
seen that of the 1.02 p. p. m. loss occurring when the mud was in contact with the dilution water during the whole procedure, 0.88 p. p. m. occurred during the acid-permanganate treat
ment and 0.14 p. p. m. can be ascribed to the alkalinization and final acidification period. With the azide modification, the greater portion of the loss also occurred during the acid- azide treatment. When the regular Winkler procedure is used 0.77 p. p. m. of the total loss takes place during the final acidification period and 0.16 p. p. m. during the alkalinization period. Finally, in the case of the short Winkler method increasing the period of alkalinization to 5 minutes increased the total loss only 0.09 p. p. m. Approximately 50 per cent of the loss occurring during the final acidification period takes place in the first 0.5 minute.
A comparative study of various methods for determining dissolved oxygen in 1/500 dilutions of river mud showed that alkaline hypochlorite treatment was superior to hypochlorite treatment in an acid medium. A number of variations of the Theriault and McNamee (4) alkaline hypochlorite procedure were tried, using various contact periods for the chlorine.
If the suspended solids were removed by either centrifuging or flocculation after alkaline hypochlorite treatment, a higher dissolved oxygen content was obtained. This showed that the alkaline hypochlorite treatment was not completely effective in oxidizing interfering substances.
It may be assumed that if the interference was caused by sulfides, these could be removed by treatment with a copper salt. Treatment with varying quantities (2 to 10 ml. per liter) of a 5 per cent copper sulfate solution for 10 minutes before continuing with the Winkler procedure gave dissolved oxygen results that were lower than those obtained following flocculation with alum. A number of coagulating agents were tried, including salts of iron, nickel, copper, lead, and titanium, but none of these showed any advantage over alum in regard to dissolved oxygen recovery, and experi
ments on their use were not continued.
A condensed summary of the results obtained in this com
parative study of procedures is given in Table III. It will be noted that the percentage of recovery of the initial cal- For these experiments a dilution of mud
was prepared in 4 liters of dilution water.
After 10 to 30 minutes of contact with the water, the suspended solids were centri
fuged out and resuspended in fresh dilution water. In this way the soluble materials contained in the original mud were largely removed and the effect of the suspended solids only on the dissolved oxygen deter
mination could be followed. In these ex
periments 10-ml. portions of this suspen
sion containing 101 mg. of suspended solids were added to 300-ml. dissolved oxygen bottles completely filled with portions of the same dilution water at the point in the procedure being studied.
The results of this series of experi
ments are given in Table II. In the case of the Rideal-Stewart modification it is
Ta b l e I I I . Su m m a r y o p Re s u l t s o f Co m p a r a t i v e St u d y o p Di s s o l v e d Ox y g e n Pr o c e d u r e s
( O n 1 / 5 0 0 d ilu tio n s o f r iv e r m u d ) N o . o f
C o m - p a r a t iv e O b s e rv a
D is s o lv e d P e r c e n ta g e o f I n itia l O x y g e n C a lc u la t e d
M e t h o d tio n s D is s o lv e d F o u n d b y In itia l
M e t h o d R a tin g O x y g e n M e t h o d F o u n d b y
S tu d ie d N o . T r ip lic a t e )
.
( C a lc u la te d )P . p . m .
S tu d ie d P . p . m .
M e t h o d
R id e a l-S t e w a r t 7 4 8 . 3 9 5 . 5 7 6 6 . 3 9
S h o r t W in k le r 6 6 8 . 6 5 5 . 7 6 6 6 .5 9
A lk a lin e h y p o c h lo r ite 5 5 8 . 1 2 6 . 9 5 8 5 . 5 9
C e n tr ifu g e 4 8 8 . 3 0 7 . 4 6 8 9 . 8 7
A lk a lin e h y p o c h lo r ite
4- a lu m flo c c u la tio n 3 4 8 . 5 5 8 . 0 0 9 3 . 5 0
A lu m flo c c u la tio n 2 9 8 . 2 9 7 . 7 6 9 3 . 6 0
I o d in e -f- a lu m f lo c c u
la tio n 1 4 8 . 6 0 8 . 1 3 9 4 . 5 0
DECEMBER 15, 1940 ANALYTICAL EDITION 713
Ta b l e I V .
culated dissolved oxygen ranged from 66.39 for the Rideal-Stewart modification to 94.50 for iodine treatment and flocculation.
This last method consists of adding a slight excess of iodine solution to a slightly acid suspension of the mud, allowing it to react for 3 to 4 minutes, then carefully de
stroying the excess with a dilute solution of sodium sulfite. The regular alum floccu
lation procedure is then followed. On the basis of percentage of initial dissolved oxygen recovered, the methods rate in
the order shown. On the basis of ease of --- manipulation and reliability, the plain alum
flocculation or centrifuging procedures are to be preferred.
Removal of Materials Interfering with Dissolved Oxygen Determination
As the biochemical oxygen demand is dependent upon a final oxygen content after an incubation period, the time in
tervals required to destroy or oxidize these materials in an aerobic mud dilution should be determined. Several experi
ments with this purpose in view were performed. Early in this study it was noted that when suspensions of mud were acidified small amounts of hydrogen sulfide were released.
The sulfides were determined by siphoning the suspension under examination into 250-ml. centrifuge bottles until completely filled, adding 2 ml. of concentrated sulfuric acid, stoppering, and centrifuging for 5 minutes. Then 100-ml. portions of super
natant were siphoned off and titrated immediately with a stand
ard 0.025 N iodine solution. Using this procedure the sulfides in a 1/250 dilution of mud under aeration for 5 hours were deter
mined at intervals.
The results shown in Table IV indicate that sulfides are removed rather rapidly under these conditions and that only about 10 per cent remain after 5 hours. The inter
ference with the dissolved oxygen determination by the alum flocculation method was also determined on the same sample initially and after 1 hour of aeration, and 65.5 per cent of the initial interference was observed after 1 hour. This and other experiments indicated that the insoluble sulfides in the mud were not the only materials interfering with the dis
solved oxygen determination. In another experiment in which the removal of the interference with the dissolved oxygen determination only was followed it was found that 42.7 per cent of the initial interference remained after 5 hours of aeration. In an experiment in which the sample was aerated for 48 hours, 14.5 per cent of the initial interference remained after 24 hours and 10.9 per cent after 48 hours.
The indications are that the other interfering materials are removed at a lower rate than the sulfides by aeration and that precautions must be taken in determining the final dis
solved oxygen concentration of mud dilutions even after several days’ incubation.
Determination of Biochemical Oxygen Demand on River Muds
The difficulties encountered in determining biochemical oxygen demands of river muds may be illustrated by the oxygen depletions calculated from the dissolved oxygen data obtained in an experiment with a 1/2000 dilution. The de
pletions obtained are shown in Table V.
The ordinary method of determining oxygen depletions as illustrated in A, using the short Winkler method, gives fallacious results on mud dilutions for two reasons. First, the 0.90 p. p. m. apparent immediate depletion, which is largely an interference and not a depletion, is not included by
Re m o v a l o f Su l f i d e s a n d Di s s o l v e d Ox y o e n De t e r m i n a t i o n In t e r f e r e n c e
( B y a e r a tio n o f 1 /2 5 0 m u d d ilu tio n )
- S u lfid e s — — D is s o lv e d O x y g e n —
S ta n d a rd A lu m
io d in e S u lfid e S h o r t flo c c u I n te r
A e r a tio n s o lu tio n re W in k le r l a tio n I n te r fe re n ce
T im e u sed S u lfid e m a in in g m e th o d m e th o d fe re n ce r e m a in in g
I I OUTS M l./ 1 0 0 ml. P . p . 771. % P . p . tn. P . p . 771. P . p . 7/1. %
0 1 .4 4 5 . 2 3 1 0 0 3 . 1 3 . 7 . 1 7 4 . 0 3 1 0 0
0 . 5 0 . 8 0 2 . 8 0 5 3 . 5
1 0 . 5 5 2 . 0 0 3 8 . 2 6^32 8 . 9 6 2^ 64 6 5 . 5
2 0 . 3 5 1 .2 7 2 4 . 3
3 0 .2 G 0 . 9 4 1 8 .0
5 0 . 1 5 0 . 5 4 1 0 .3 . .
Ta b l e V . Ox y g e n De p l e t i o n s '---O x y g e n D e p le tio n s
C a lc u la te d O b s e rv e d In itia l In itia l D . Ô . — D . O . - -O b s e r v e d O b s e r v e d F in a l F in a l D . O . ( A ) D . O . (B )
A lu m A lu m
flo c c u la flo c c u la
S h o r t tio n S h o r t t io n
I n c u b a t io n T im e W in k le r m e th o d W in k le r m e t h o d D a y s P . p . 771. P . p . m . P . p . 77*. P . p . 77*.
I m m e d ia t e (a p p a r e n t
in itia l d e p le t io n ) 0 . 9 0 0 . 0 6
1 1 .4 0 l'.5 S 2 . 3 0 1 .6 4
2 2 . 1 7 . 2 . 7 2 3 . 0 7 2 . 7 6
3 2 . 2 7 3 . 1 7
4 2 .8 2 3 * 2 3 3 . 7 2 3 ! 29
the method. Secondly, the final dissolved oxygen observa
tions after incubation may also be low, owing to interference.
Consequently, the ordinary procedure for determining de
pletions gives results which are too low.
With the short Winkler procedure, because of the unreli
ability of the dissolved oxygen results following incubation, the depletion obtained from the calculated initial dissolved oxygen, shown in B, will be too large for the first few days dur
ing the incubation period. Consequently, this procedure is also unreliable and cannot be recommended. With the alum flocculation procedure there was little interference in the initial dissolved oxygen determination as indicated by the very small apparent initial depletion, 0.06 p. p. m., in this case.
Therefore, the results obtained following the alum flocculation procedure should be more reliable and produce closer approxi
mations to the true oxygen demand, regardless of whether method A or B is used to determine the depletions. Whether that portion of the demand represented by the immediate oxygen loss, obtained with the use of a corrective dissolved oxygen procedure, would represent a true chemical or bio
chemical demand is an unanswered question. But in any case the results of this procedure would approximate the total demand for oxygen of the mud under examination and that is the important factor.
Another phase that should be considered in the deter
mination of the oxygen demand of river muds is the effect produced by the settling out of the suspended particles as occurs in the use of the regular method of determining B. O. D.
This concentration of the solids in the bottom of the bottles might result in the deoxygenation of the water immediately surrounding the mud particles. This would change the proc
ess taking place from one of complete aerobic dissimilation to one in which anaerobic dissimilation took place in the bottom of the bottle and aerobic dissimilation only in the layer above the mud.
With tills fact in mind, an experiment was carried out in which the mud particles were kept in suspension by a con
tinuous rotation of the bottles in a specially constructed ap
paratus kept in the 20° C. incubator and rotating about 1 r. p. m. A duplicate set of samples was also placed in the same incubator and allowed to stand quiescently during the period of the test.
