Determination of Small Concentrations of Sodium PATRICK MAZZAMARO, U n i t e d Chromium, Inc.,
GEORGE TATOIAN, Patwin lnstruments Division,
W a t e r b u r y , Conn.
Patent Button Co., W a t e r b u r y , Conn.
T
HE presence of sodium in distilled water and sulfuric acid is of importance to a new theory of hydrogen overvoltage ( 2 ) . The detection and determination of sodium in distilled water and sulfuric acid obtained from various sources and stored in different types of containers were accomplished through use of the flame photometer method. This method is similar to that of Berry, Chappell, and Barnes ( I ) , but has been adapted for concentrations with a lower limit of 6 X lo-’ gram equivalent per liter with relative ease and accuracy. PROCEDURE
The determinations were made by the so-called “absolute or direct” method on a Barclay flame photometer, using the center channel for maximum sensitivity. The gas was ignited and the instrument was allowed to reach equilibrium. A solution containing sodium which was to be determined was atomized by use of an atomizer made from two standard No. 19 B. 8: D. hypodermic needles. This atomizer uses 10 ml. of solution per 30 seconds. The aerosol then passes into the propane gas flame of a special Meker-type burner. The characteristic spectrum of sodium then passes through two Fresnel lenses and the Corning sharp cutoff filters to the standard Barclay barrier layer photoelectric cell selected for high sodium output. I
two samples of distilled water from a Barnsted still, which were stored in polyethylene and glass containers. The third determination was made on triple-distilled water from a laboratory glass still. None of the above samples showed any trace of sodium, as indicated in Table 11. The sulfuric acid samples checked for sodium content were of reagent grade and redistilled sulfuric acid from an Armco iron still. The solutions were made 2.LI- sulfuric acid (5.7% by volume) and were standardized against sodium carbonate with methyl orange as the indicator. The samples were stored in polyethylene containers.
Table 11. Determination of Sodium in Samples of Distilled Water and Sulfuric .4cid
Distilled water (Armco iron still) Distilled water (Barnsted still.. no elass contact) Distilled water (Barneted still, glass contact) Triple distilled water 2.!0,\- HaSOd (reagent grade)
Scale Reading, hlm. 0 0 0 0
Sodium Concentration,
G. Equiv./Liter
Less than 6 X 10-7 Less t h a n 6 X 10-7 Less than 6 X 10 - 7 Less than 6 X l o - :
2
17 & 1 4 & 1
1 . 0 5 X 10.1 0 . 2 2 x 10-5
2
11 f 1 17 =k 1
0 . 7 2 X 10-5 1 . 0 5 X 10-6
I
2 . 1 0 s HA04 (redistilled) 1
DISCUSSION
Figure 1. Absolute Circuit of Barclay Flame Photometer
After the sodium spectrum is converted to electrical energy it is measured quantitatively by a high sensitivity General Electric galvanometer (Catalog No. 32C246G9, internal resistance 1900 ohms, CDRX 42000 ohms, sensitivity 0.000655 pa. per mm.). The electrical circuit is shown in Figure 1. The A and B potentiometers were set a t maximum sensitivity. Five standard solutions of sodium, ranging from 1 X 10-6 to 4.36 X gram equivalent per liter (1 p.p.m. j, were made. The flame output was used as galvanometer zero. All samples were measured above this level.
For all practical purposes, the distilled water obtained from various sources is substantially free from sodium. Contact with glass or polyethylene a t room temperature did not seem to contaminate the distilled water over a period of a week or two. The results obtained with sulfuric acid varied regardless of the source. Sherman ( 3 )states that sulfates have a pronounced specific effect on the determination of sodium by flame photometry.
Table I. Determination of Sodium in Various Standard Solutions Concentration, G. Equiv./Liter Flame 1 x 10-5 2 x 10-5 3 x 10-5 4
x
Scale Reading, hf m. 0 16 i 1 30 i 1 47 & 1 67 & 2 72 s 2
10-5
4.36 X 10-j
U
I
0 0
10
1
f
80
30 SCALE
Figure 2.
By plotting concentration us. scale reading of Table I, a calibration curve, Figure 2, was constructed. EXPERIMENTAL
The first determination was made on two samples of distilled water obtained from an rlrmco iron still, and stored in polyethylene containers for 1 year. A second determination was made on
I
40 50 READING
I
I
60
70
Calibration Curve
If the effect obtained in this work were caused by the sulfuric acid, then a constant value should have been found, since the acid concentration was maintained constant. However, as the results varied, it seems probable that the sulfuric acid may have been contaminated with sodium, or that there may be a reaction 1512
V O L U M E 2 6 , NO. 9, S E P T E M B E R 1 9 5 4
1513
between sulfuric acid and glass upon storage which leaches out sodium. .4CKNOWLEDGMENT
The authors wish to acknowlege the assistance of Joseph V. Petrocelli, Patent Butt’on Co., and of George Dubpernell and llichael Orient, United Chromium, Inc.
LITERATURE CITED
(1) Berry, J.
W-.,Chappell, D. G . , and Barnes, R. B., IND. EXG.
CHEM.,ANAL.ED.,18, 19-24 (1946). (2) Dubpernell, G., and Dubpernell, R., Plating,40, 53, 151 (1953). (3) Sherman, J., in “Physical Methods in Chemical Analysis,” edited by W. G. Bed, pp. 330-1, Sew York, Academic Press, Inc., 1950.
RECEIVED f o r review October 6, 1993. Accepted May 11, 1954.
Decay and Growth Tables for the Naturally Occurring Radioactive Series-Correction Significant errors appear in my paper, “Decay and Growth Tables for the Naturally Occurring Radioactive Series” [ A S A L . CHEM.,26, 1063-71 (1954)]. Corrections are as follows: Table V, column 5 , page 1064, should read: ____ Time, Days
Time, Days
0.0000 0.1677 0.4476 0.7083 0,9296 1.1136
26 27 28 29 30
6 7 8 9 10
1.2655 1.3908 1.4941 1.5791 1.6490
31 32 33 34 35
1.9442 1.9434 1.9423 1.9411 1.9398
11 12 13 15
1.7066 1.7536 1.7923 1.8239 1.8497
36 37 38 39 40
1.9384 1.9369 1.9353 1.9336 1.9319
16 17 18 19 20
1 ,8706 1.8876 1.9013 1.9123 1,9210
41 42 43
1.9302 1.9284 1.9266 1.9248 1.9230
21 22
1 ,9279 1.9333 1.9373 1 ,9404 1.9428
46 47 48 49
23 24 25
44
45
50
pl/.\-oxI
Hours 0 1 2 3
-
Bt/SoX1
14
Table XXI, column 3, page l O i l , should read for thorium-228:
pl/soxi
4
1.9440
6 7 8
1,9449
1.9483 1.9452 1,9449
0.0000 0,0003 0.0013 8.0031 0 0057 0.0091 0.0132 0.0180 0,0235 0,0295 0.0362 0 0433 0,0809 0.0589 0.0674 0.0762 0 0853 0 0948 0 1045 0 1145 0 1248 0 1352 0 1459 0 1567 0 1677 0 1900 0 2128 0 2389 0 2593 0 2829 0 3065 0.3302 0.3538 0,3775 0,4010
R
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 28 30 32 34 36 38 40 42 44 46 48
1.9211 1.9193 1.9174 1.9155 1.9137
Table VII, Column 4, page 1065, should read:
0,4244
0.4476 0.4935 0.5385
52
56 Time, Hours 0 1 2 3 4
5 6 7 8 9 10 11 12 15
18 21 24 30 36 42
48
54 60 66
72 78 84 90 96 102 108 114 120 126 132 138 144
0 . ,5826
60
Bl/.VOXl 0.0000 0.0779 0.1749 0.2766 0.3769 0.4729 0.5634 0.6479 0.7265 0.7994 0.8668 0.9290 0.9865 1.1326 1.2462 1.3303 1,3930 1,4673 1.4930 1.4869 1.4606 1.4217 1.3751 1.3244 1.2717 1.2186 1.1660 1.1146 1.0646 1.0164 0.9700 0,9254 0,8828 0.8420 0.8031 0.7658 0.7303
0 6256 0 6675 0 7083 0.7865 0.8603 0.9297 1,0260 1.1136
64
68 72 80 88 96 108 120
Table IV, page 1064, should read: x iax-o -
(Po212)
(Tl208)
’VOX,
?& SOX1
-
663
.\.B“B
x ox1
0 33902e-X11 - 0 39034e-h2t
+ - 0 00044e-X6f
0 05177e-Xbt
Noh1
=
2 01190e-X1t - 2 30206e-X2t A 029145e-X’f
- 0
00127e-X6f
Table TI,page 1065, should read: (Tlzoa)
s6hS = .vox1
0 38829e-X1t
- 0 42652e-x41 f 0 03835e-A5t
Bt= 2 .\‘OX 1
28997e
+ 0 0 1 l 1 4 2 e - ~-~ ~2
*OlZle-X4t
-0
00012e-X‘t
-0
00012e-X‘t
+
0 10994e-X6t
H. W. KIRBY
