Physical Methods In Chemical Analysis

PHYSICAL METHODS IN CHEMICAL ANALYSIS Edited by WALTER G. BERL Applied Physics Laboratory, Johns Hopkins University, Silver Spring, VOLUME π 1951 ACADEMIC PRESS INC. PUBLISHERS NEW YORK Maryland COPYRIGHT © 1951 BY ACADEMIC PRESS INC. ALL RIGHTS RESERVED. NO PART OF THIS BOOK MAY BE REPRODUCED IN ANY FORM, BY PHOTOSTAT, MICROFILM, OR ANY OTHER MEANS, WITHOUT WRITTEN PERMISSION FROM THE PUBLISHERS. A C A D E M I C PRESS INC. I l l Fifth Avenue, New York, New York 10003 United Kingdom Edition published by A C A D E M I C PRESS INC. ( L O N D O N ) Berkeley Square House, London W.l LTD. First Printing, 1951 Second Printing, 1967 PRINTED IN THE UNITED STATES OF AMERICA CONTRIBUTORS T O VOLUME II WALTER G. The Applied Physics Silver Spring, Maryland Laboratory, BERL, University, Washington Singer Laboratories, the South West of England, Exeter Η . T . S. BRITTON, BENJAMIN B. MALCOLM DAYTON, Distillation Department Illinois of Chemistry, DOLE, Evanston, H. W . HERMANCE, Bell Telephone Laboratories, JAROSLAV HEYROVSKY, GEORGE JURA, Products, University of Prague, Department of Chemistry, Johns University Hopkins College of Inc., Rochester, New Northwestern York University, Inc., New York, New York Czechoslovakia University of California, Berkeley, California Department of Metallurgy, Technology, Cambridge, Massachusetts A. R. KAUFMANN, H. A. LAITINEN, Department of Chemistry, Massachusetts Institute University of Illinois, Laboratories, East of Urbana, Illinois ALOIS LANGER, Westinghouse Research Pittsburgh, Pennsylvania J. SHERMAN, Philadelphia Η. V. WADLOW, E. R. WEAVER, Naval Shipyard, Philadelphia, Bell Telephone Laboratories, National Bureau of Standards, ν Pennsylvania Inc., New York, New Washington, D. C. York PREFACE T h e contributions included in this volume continue t h e aims set forth in Volume I t o describe those physical m e t h o d s t h a t h a v e either proved of considerable value in analytical work or are destined t o play a n import a n t role in t h e future. Electrical, magnetic, a n d miscellaneous t e c h niques are discussed. I n addition, a c h a p t e r on t h e statistical analysis of experimental d a t a is included. I n carrying out an analysis t h e a n a l y s t usually performs t w o major tasks: 1) preliminary operations t h a t bring t h e system u n d e r investigation into physical s t a t e s suitable for analysis, 2) m e a s u r e m e n t of physical c o n s t a n t s t h a t can be compared with k n o w n systems for i d e n t i t y or can be interpreted in t e r m s of s t r u c t u r e a n d organization. A m o n g t h e preliminary operations are included such changes in struct u r e a n d phase as m a y be necessary for t h e subsequent physical measurem e n t (ionization in t h e mass spectrometer, vaporization a n d heating in emission spectroscopy, etc.) a n d t h e m a n y techniques of separation (distillation, distribution between immiscible solvents, separation of ions in a magnetic field, etc.). T h e d e t e r m i n a t i o n of physical c o n s t a n t s leads t o identification as t o t y p e a n d n a t u r e of t h e s t r u c t u r e u n d e r investigation (qualitative analysis). If a definite relation between physical cons t a n t a n d concentra