NEWER METHODS FOR THE SPECTROCHEMICAL ANALYSIS OF SOLUTIONS

82 Pages·03.25 MB·English

by  MOSHER, ROBERT E

NEWER METHODS FOR THE SFECTROCHENICAL
ANALYSIS OF SOLUTIONS
A Dissertation
SUBMITTED TO THE GRADUATE COUNCIL OF WAYNE UNIVERSITY
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
THE DEGREE OF DOCTOR OF PHILOSOPHY
IN THE DEPARTMENT OF CHEMISTRY
by
Robert E. Mosher
Detroit, Michigan
19h9
'
Ofry.i
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*^V3RAr?y o}
WAYME. UNIVERSITY
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PREFACE
Review of the literature reveals that spectrochemical
analysis of solutions per se has not been satisfactorily solved. In
most cases the emission spectrographs technique yields data of
questionable accuracy. In consequence of these difficulties attempts
have been made to evaporate and pelletize solutions preparatory to
employment of arc or spark excitation. Probably the most commonly
used procedure is to drop the solution to be analyzed into a paraffin-
dipped craterized carbon electrode, which is then thoroughly dried
before electrical excitation. Diffusion of the various cations through
electrode surface material, usually necessitates burning of the whole
sample by arc technique, which is less easily manipxtlatedt han spark
procedures. These procedures are time-consuming, allow the possible
introduction of impurities, and deal primarily with solids.
A portion of this thesis describes the successful useo f a
rotating disc electrode manufactured by the Applied Research
Laboratories and modified in this laboratory for purposes of direct
quantitative solution analysis of magnesium-bearing ores. The numerous
difficulties concerning time, precision and accuracy of emission
spectrographic analysis of solutions were overcome through this device.
A more limited quantitative spectrochemical analysis of
solutions may be achieved by flame excitation. A part of this thesis
treats the use of the newly-developed Beckman flame photometer and its
use in the successful quantitative analysis of sodium and potassium in
human plasma and urine as 'well as the quantitative estimation of low
concentrations of calcium in magnesium-bearing ores. A critique of
ii
flame band and line spectra is presented with experimental evidence of
instrumental characteristics and factors affecting specific elemental
intensities.
iii
TABLE OF CONTENTS
Page
Preface . ii
List of Tables vii
List of Illustrations. vi
Section I: Flame Photometry
Chapter
I. HISTORICAL REVIEW 1
II. DESCRIPTION OF THE BECKMAN FLAME PHOTOMETER 11
III. INSTRUMENTAL VARIABLES Hi
A. Consideration of Gases lU
B. Spray Chamber 15
C. Atomizer 16
D. Burner Assembly 16
E. Types of Spectra. 1?
F. Solution Variables 18
G. Comments . 20
IV. PROCEDURES FOR THE SOLUTION ANALYSIS OF HUMAN PLASMA AND
URINE FOR SODIUM AND POTASSIUM 21
V. DISCUSSION AND RESULTS 26
VI. PROCEDURES FOR THE SOLUTION ANALYSIS OF MAGNESIUM—BEARING
ORES FOR CALCIUM 35>'
VII. DISCUSSION AND RESULTS 38
Section lis Spectrography
VIII. INTRODUCTION AND HISTORICAL REVIEW
IX. INSTRUMENTATION . b5
X. APPARATUS AND SPECTROGRAPHS! CONDITIONS U6
iv
XI. PROCEDURES FOR THE SOLUTION ANALYSIS OF MAGNESIUM-BEARING
ORES FOR CALCIUM, IRON AND ALUMINUM U8
XII. DISCUSSION AND RESULTS £l
BIBLIOGRAPHY ££
BIOGRAPHICAL STATEMENT 58
v
LIST OF ILLUSTRATIONS
Figure
I. The Beckman Flame Photometer
II. Atomizer, Spray Chamber and Burner Assembly
III. Snectrum of Natural Gas Flame from 800 to 1200M U.)
)
IV. Spectrum of Natural Gas Flame from 305 to 317 MU.)
V. Oxygen Maxima Curves for Sodium
VI. Oxygen Maxima Curves for Potassium
VII. Oxygen Maxima Curves for Calcium
VIII. Resolution of a Potassium Doublet
IX. Typical Flame Spectra
X. Relation Between Concentration of Standard and Intensity Values
XI. Flame Spectrum of Sodium and Calcium
XII. Effect of 873090 Filter on Calcium andS odium Spectrum
XIII. Influence of Iron, Aluminum and Magnesium on Calcium Emission
XIV. Rotating Disk Electrode
XV. Working Curve for Iron )
)
XVI. Working Curve for Aluminum)
XVII. Working Curves for Calcium)
vx
(
LIST OF TABLES
Table Page
I. Additions °** Sodium as Chloride to Analyzed Pooled Plasma#.,. 27
II. Additions of Potassium as Chloride to Analyzed Pooled
Plasma - 27
III. Effect of Gelatin on Intensity in SodiumM easurements...... 28
IV. Effect of Gelatin on Intensity in Potassium Measurements..• . 29
V. Sodium and Potassium Values of 72 Normal Plasma Samples
Analyzed Spectrographically and Flame Photometrically........ 31
VI* The Combined Effect of Magnesium, Iron and Aluminum on
Calcium Intensity hZ
VII. Additions of Known Amounts of Calcium to an Analysed
Magnesite Sample U3
VIII. Comparison of Caley-Elving and Flame-Photometric Methods
for CaO. U3
3X. Spec tro graphic Analyses of Ilagnesite ^1
X. Recoveries of Known Amounts of Calcium, Iron and Aluminum
from Magnesite 53
XI. Replicate Analyses of a Magnesite Ore.
vii
SECTION I
FLAKE PHOTOMETRY
CHAPTER I
HISTORICAL REVIEW
It has long been known that elements subjected to high
temperatures induced by electrical or other means emit characteristic
spectra, the intensity of which is a function of concentration. This
phenomenon has been utilized for the qualitative detection and more
recently for the quantitative estimation of numerous elements in both
free and combined states,
Bunsen and Kirchoff are credited with the initial discovery in
i860"*" that solutions containing alkalies and alkaline earth metals,
respectively, give rise to characteristic colors when injected intoa
gas flame. This finding was soon utilized as a method of detecting
elements of these groups. Even today it is an accepted technique for
visually identifying sodi\im, potassium, calcium, strontium, barium and
several other elements.
The first serious study of the spectra of colored flames is
recorded in a series of very interesting papers published by Hemsalech
and de VFatteville in the early part of this cent\^ry.^,^,^,*'
1, Kirch off, C-., and Buns en, R., Pogg. Ann. 110: 16 (i860),
2, Hemsalech, G. A., and de Vfatteville, C., Compt.R end. lUU:
1338-UO (1907).
3, Ibid., ll£: 1266 (1907).
U. Ibid.1 1U6: 7U8-51 (1908).
5. Ibid., 1U6: 859-62 (1908).
6* Ibid., 1U6: 962-65 (1908).
7. Ibid., Ik6: 1389-92 (1908).
8« Ibid., 1U9: 1112-15 (1909).
9* Ibid., l£0: 329-32 (1?10).