Table Of ContentAcknowledgment
The writer wishes to express his
appreciation to Dr. John R. Kayes for his
helpful advice during the course of this
work.
The Pennsylvania State College
The Graduate School
The Department of Chemistry
ilications of Ion Exchange in Analytical Chemistry
Part I Determination of Organic Salts
Part II Determination of Boron
A thesis
by
J. Robert Martin
Submitted in partial fulfillment
of the requirements
for the degree of
Doctor of Philosophy
June 1950
Approved:
Department of Chemistry
Table of Contents
Page
A c kn owl ed gment
Introduction 1
Part I Determination of Organic Salts 7
A. Discussion 7
B. Materials and Apparatus 9
1. Choice and Preparation of Resin 9
2. Reagents 13
3. Standardization of Solutions 15
4. Apparatus 17
C. Experimental 19
1. Preliminary Investigation 19
2. Studies on Blank 20
(a) Variation with Amount of Rinse 20
Effect of Resin Conditioning 21
Comparison of Resins 22
<e)
(d) Effect of Yi/ater Purity 23
(e) Variation with Amount of Resin 25
<*) Effect of Resin Aging 25
Constancy of Blank 26
(g)
Conclusions 26
Determination of Organic Salts 27
(*) General Procedure 27
(1) S odium Oxalate 28
(2) Potassium Acid Phthalate 29
Preparation of Standard Salt Solutions from 30
<*)
the Acids
8 4 8 6 7 2
Table of Contents (continued) Page
(1) Correction for Carbonate 31
(a) Stoichiometry of Bicarbonate Exchange 32
(b) Determination of Carbonate in Alkali 33
Solutions
(2) Procedure A - Removal of Carbon Dioxide 35
by Volatilization
(a) Sodium Salicylate 35
(b) Sodium Benzoate 36
(3) Procedure B - Application of Correction 37
for Carbonate in Alkali
(a) Sodium Acetate 37
(b) Sodium Adi pate 38
(c) Sodium Chloroacetate 38
(d) Sodium Maleate 39
(e) Sodium Malonate 39
(f) Sodium Tartrate 39
(c) Correlation of Rinse Requirements and Solubility 40
D. Summary 41
Part II Determination of Boron 43
A. Introduction 43
B. Materials and Apparatus . 47
1. Choice and Preparation of Resin 47
2. Reagents 47
3. Apparatus 49
C. Measurement of Boron Concentration 50
D. Experimental 52
1* Titrimetric Determination of Boron 52
Table of Contents (continued) Page
(a) Procedure 57
(b) Standardization of Sodium Hydroxide Solutions 57
(c) Effect of Electrolytes 58
2. Study of Blank 60
3. Resin Rinse Requirements 62
4. General Procedure 63
5. Separation of Boron from Cations 63
(a) Iron 64
(b) Aluminum, Beryllium, Magnesium, and Zinc 64
(c) Cadmium, Cobalt, Copper, Mercury, and Nickel 65
(d) Thorium, Tin, Titanium, Uranium, and Zirconium 65
6. Interference of Anions 66
(a) Chromate, Permanganate, and Vanadate 67
(b) Arsenate, Phosphate, and Molybdate 68
(c) Silicate 70
7. Determination of Boron in Commercial Materials 71
(a) Steel 72
(b) Ferroboron 73
(c) Casting Alloy 74
(d) Nickel Plating Solutions 75
8. Discussion 76
E. Summary 78
F. Bibliography 80
SOME APPLICATIONS OF ION EXCHANGE IN ANALYTICAL CHEMISTRY
INTRODUCTION
The phenomenon of ion exchange was first observed in soil by Way3,
in 1850 and a considerable investigation of naturally occurring exchange
materials followed. Tswett in 1906 utilized these materials in a column
to separate biological pigments chromatographically but the application
of the principle to analytical procedures was seriously hampered by the
low capacity and chemical instability of the natural exchangers. In the
early 1900's the preparation of synthetic exchangers was investigated
and this work advanced markedly, producing in recent years exchangers
of high capacity and excellent stability thereby opening a field of ana
lytical utilization of ion exchange techniques.
It is not the purpose of this thesis to present an extensive
review of the applications of ion exchange in analytical chemistry since
several excellent treatments of this subject have already been pub-
3 4 5
lished 9 3 , but a brief resume emphasizing pertinent experimental work
is included to provide a basis for the development of the problems en
countered in this work.
The first practical utilization of ion exchange for chemical
6
analysis was achieved by Folin and Bell in 1917 • They found that the
determination of ammonia in urine by means of the familiar Nessler's
reagent was unsatisfactory because of interference by creatinine but
passing the urine solution through a column containing sodium saturated
Permutit and eluting with sodium hydroxide solution separated the ammonia
free of creatinine and the Nessler method could then be satisfactorily
applied.
Page 2
In general, the applications of ion exchange in analytical
chemistry may be classified as (1) concentration of dilute solutions,
(2) removal of interfering ions, (2a) separation of cations from anions,
(2b) fractionation of ions, (3) miscellaneous.
Ion exchange materials have been successfully utilized as col
lectors for concentrating solutions which are so dilute with respect to
the desired constituent that analytical measurements are inadequate for
an accurate determination. The degree of concentration possible is con
trolled by the exchanger capacity and the type and concentration of the
eluting solution which may be tolerated but the method provides advan
tages of speed, simplicity, and freedom from contamination. The procedure
has been applied to the determination of traces of copper in milk7 and
shows promise for determination of trace elements in plant materials8.
One of the basic problems of analytical chemistry is the isolation
of the constituent to be measured free from interfering compounds. In
the case where the interfering ion is carrying a charge opposite to that
of the ion to be measured, a separation may be easily achieved by passing
the solution through either an anion or cation exchanger. Samuelson9 16
has studied a great many of these systems and his results are summarized
in Table I. Some applications of this principle to specific procedures
are given in Table II.
Many instances exist where the interfering ion and the ion to be
measured carry a charge of the same sign but here again ion exchange may
provide a separation by fractionating cations or anions in a manner
similar to chromatography. Outstanding examples of the use of this prin—
X7 16
ciple are the separation of rare earths and amino acids . This field
of research has been of considerable value from the preparative point of
Page 3
view as well as from the analytical approach. Separations may be based
on differences in exchange potential, valence, ionic size, basicity or
acidity, and reaction with eluting solution. Other separations made
possible are sodium from potassium*9 or calcium20, chloride from sulfate21,
2 o
weak acids from strong acids , weakly basic alkaloids from quinine and
33 24
brucine , and ammonium ion from tetramethyl ammonium ion
Page 4
Table I
Separation of Anions and Cations by Ion Exchange
I
I
Cl I Br SOJ CIO* po| C20J cio; Okc
Li+ X X X X X X X X
Na+ X X X X X X X X X X
K+ X X X X X X X X X X
nh4+ X X X X X X X X X X
Mg++ X X X X X X X X X X
Ca++
X X X X X X X X X X
Sr++ X X X X X X X X X
Ba++ X X X X X X X X X
Al+++ X X X X X X 0 X X
Pb++ 0 X
V0++ X
Cr+++ X X X1 X x2 X
Mn++ X X X X X X X X X
Fe+++ X X X X 0 X X
Co++ X X X X X X X X X X
Ni++ X X X X X X X X X
Cu++
X X X X
Zn++
X X X X X X X X X X
Cd++
X X X X X X X X X
Fe++
X
Be++
X
x — quantitatively separated
0 - not separated
1 - partially separated
2 - quantitatively separated only in fresh solutions
Table II Procedures anploying Ion Exchange for
Removal of Interfering Ions
Determination Procedure Interferences Re
moved, References
1. Sulfate a. Pass solution through HR and precipitate as BaSO* Na+, Ca++, Few 2S=26
(in water) b. Pass water through HR, add excess BaCl2, and titrate Ca«, Bg+* 27
with K-palmitate to phenolphthalein end point.
26
2. Chloride Pass solution through NaR and use Mohr titration. Ba++, Pb++, H'
3. Selenite Pass solution through HR and analyse polarographically. Fe+++, Al+++, Co++ Mn++
4. Sodium a. Pass solution through anion exchanger and precipi Pof, MoOT 11j12»29
Potassium tate as Zn or Mg uranyl acetate.
b. Pass solution through HR or UH4R, elute with HC1, voi, so;,= 30, 31
and precipitate as above or evaporate to dryness,
bake, dissolve, and titrate with AgN03.
5. Silica Pass solution through HR and determine colorimetrically. Ca++, Fe+++ 32
6. Phosphate Dissolve sample in HC1, evaporate and bake to stabilize Fe+++, Al+++, Cr+++ 33
in rocks Si02 and remove F“. Take up in dil. HC1, pass through
HR, adjust pH to 4.63 and titrate to a pH of 8.89.
7. Arsenate Dissolve sample, oxidize, evaporate, redissolve, pass Fe+++, Cu++ 34
through HR and determine iodimetrically.
= 35
8. Fe and A1 a. Pass solution through HR, elute with HC1 and precipi POj
tate Fe and A1 in effluent with N^OH.
also Cu, Ca, b. Pass solution through chloride saturated anion ex polybasic carboxylic
and Mg changer and determine gravimetrically. acids351
9. Urea, morphine, Pass solution through HR before determination. NH,
and amino acids
in urine.
