Ion Chromatography with Low-Capacity Resins and Low-Conductivity Eluents Douglas Thomas Gjerde Iowa State University
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Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1980 Ion chromatography with low-capacity resins and low-conductivity eluents Douglas Thomas Gjerde Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Analytical Chemistry Commons Recommended Citation Gjerde, Douglas Thomas, "Ion chromatography with low-capacity resins and low-conductivity eluents " (1980). Retrospective Theses and Dissertations. 6786. https://lib.dr.iastate.edu/rtd/6786 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. 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LONDON V.'CIR 4EJ, ENGLAND 8028615 GJERDE DOUGLAS THOMAS iON chromatography WiTH LOW-CAPACITY RESINS AND LOW- CONDUCTIVITY ELUENTS Iowa Slate University PH.D. 1980 University Microfilms I ntern 6ltiO n 3.1 300 N. Zeeb Road, Ann Arbor, MI 48106 18 Bedford Row, London WCIR 4EJ, England Ion chromatography wich low-capacity resins and low-conductivity eluents by Douglas Thomas Gjerde A uisserûaôion submittec to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department : Chemistry Major: Analytical Chemistry Aooroveo.: Signature was redacted for privacy. n C of Maj r Signature was redacted for privacy. For the Dep%rtmen1 Signature was redacted for privacy. IowaT State University Arnes, Iowa ^ 9 V V ii TABLE OF CONTENTS Page irVtJT 0 AT OmTDM nTP i->TC;c;-CprnorpTnM •pn'DlVIAT' 1 GENERAL INTRODUCTION 2 SECTION I. EFFECT OF CAPACITY ON THE BEHAVIOR OF ANION-EXCHANGE RESINS 5 INTRODUCTION 6 EXPERIMENTAL 12 nEùULi'ù Id DISCUSSION 26 REFERENCES 2 7 SECTION II. CHROMATOGRAPHIC SEPARATION OF METAL IONS ON MACRORETICULAR ANION-EXCHANGE RESINS OF A LOW CAPACITY 29 INTRODUCTION 30 EXPERIMENTAL 32 RESULTS 36 CONCLUSIONS 49 REFERENCES 50 RRC'T'TriM TTT AWTOM rT-TROMflTTinP A PUV MTTln T nT.r_pn.wnTTr"nTirTryiv iri TTTATm? T T]\îrppnriTTr;rpTm\T c;o EXPERIMENTAL 5^ iii Page RESULTS 59 U-Loo uooxvji^ (0 CONCLUSIONS So REFERENCES 8l SECTION IV. ANION CHROMATOGRAPHY WITH LOW-CONDUCTIVITY ZLUENTS II 82 INTRODUCTION 83 EXPERIMENTAL 84 RESULTS 87 DISCUSSION 108 REFERENCES 110 SECTION V. EFFECT OF CAPACITY ON THE BEHAVIOR OF LOW-CAPACITY MACRORETICULAR ANION-EXCHANGE RESINS 111 INTRODUCTION 112 EXPERIMENTAL 114 RESULTS AND DISCUSSION ll6 CONCLUSIONS 125 REFERENCES 126 SECTION VI. CATION CHROMATOGRAPHY USING fl V/VINIVUU/"^rwTT^TTr^m-r-TT^rnTT _L V J.1 1 1VZ,_LT>T-ImT-«^T-N JLV 1 UT. ±^1- ^ INTRODUCTION 128 H!" " Zj j_ 3 ^ RESULTS AND DISCUSSION 133 iv Page CONCLUSIONS 154 •DiT'-pir'D-p'NTPTrc: GENERAL CONCLUSIONS I56 FUTURE WORK I57 GENERAL REFERENCES 162 ACKNOWLEDGMENTS I63 EXPLANATION OF DISSERTATION FORMAT The dissertation is divided into six sections. kvsL'S#'Q ^ v-> u-T T ^*./1 ^ v>J. /-MV-/ vx.^x ^ /-* Vs A T* r ^"T mi.-vo V» r* /-\ v- ^ ^ ^ ^ ^-v* *2/ «Î v»A A ^w A,V> A /-\ "> 10^ u.^ •> v* C*. ^"1 publication forms. The introduction in Section I is expanded to familiarize the reader with basic ion- exchange theory. Parts of several of the introductions are redundant because each section is complete by itself. Reference to tables, figures and literature apply only to those references contained within that section. The literature cited in the General Introduction and Future Work is listed in the General References list at the end of the dissertation. All of the work presented here was done under the direction and guidance of Dr. J. S. Fritz. Dr. G. Schmuckler, a visiting professor on sabbatical from the guidance for work shown in Sections III and IV. Ms. Rose Becker, a summer student, initiated work shown in Section VI under tne direction of the author. 2 GENERAL INTRODUCTION Most ion-exchangers marketed today are resins that have been functionalized to the highest possible capacity- The capacities of these ion exchangers vary from batch to batch because of the difficulties in duplicating reaction conditions. Furthermore, different polymer substrates will produce ion exchangers of different capacities because the number of sites available for functionalization changes. For example, a highly crosslinked resin will probably have O 1 4-?% 4- Tm, V, ^ n 4 r—•v-» H -î v» 1^ ^ -î v-> I.T.—» v*1 ^ ^ r* J. Cx J- W J 1/ llCtl 1 Ct »w.J. —OO-l-lA* W# V/J. fL by Fritz and Story (1,2) shows that ion-exchange capacity dramatically affects the behavior of sulfonated cation- exchangers. Distribution ratios of cations decrease with decreasing capacity. Selectivity coefficients also vary, but not in such a predictable manner. The lower capacity resins were found to be useful for many separations because lower eluent concentrations could be used. The work presented in Sections I and II in this dissertation is an extension of the work by Fritz and Story. Strong-base anion exchangers with capacities f « r t w 7 r ' w i ii i : ci ' r i i tjr-v / rr •r.ro -y» ^ i—, -v-» q ^ -*-» <3 ^ v* characterized. Distribution ratios also decrease for anions wiien anion-exchange resin capacity is decreased but selectivity coefficients are essentially constant for the anions studied. 3 Several applications of low-capacity anion-exchange resins are shown in Sections I and II. One of the more interesting applications of low-capacity resins is the use of XAD-1 0.04 mequiv./g resin in the separator column of an ion chromatograph. Ion chromatography developed by Small et al. (3) is a significant improvement in the analysis of anions. The system consists of a separator column made with a low-capacity anion-exchanger, followed by a suppressor column of high-capacity cation-exchanger in the hydrogen form. The effluent from the suppressor column is directed into a conductivity cell. The low- capacity separator column needs only a dilute eluent solution ('V'O. OOÔM) of sodium carbonate and sodi'am bicarbonate to separate sample anions. The suppressor column allows the use of a conductivity detector by converting the sodium carbonate and sodium bicarbonate i1 L/ V / Ccc T.rcioLr'TTVV ci. f\, ^ r» /-wnA 1 rs 1TV#. r» 1—iv-irrL/ 1i ^ Oc I i<-<n— V S*/r\r' ii <_A, i t ^ ^ r*Sw -L.-i n CL A A Vii^ T"-f *kn * A iD CUli_y XO OCî-J-OO wo. v-ilj-v-zx J_ y kZ) vt _L J. CL V C CLi i\-«. w v . _i_ .ii v w hlLglily COildUCtirig S.CIC.5 . Ion chromai:ography is a sensitive and useful problem solving technique but it suffers from the need for frequent regeneration of the suppressor column. In the summer of 1978, Dr. Gabriella Schmuckler, on sabbatical from TJ"o*î"Po T'ovïool o c TT o 4" 4 T»TV, "TrtVi o 4 column. Using the ion-exchange expertise already known, a working system called anion chromatography was quickly discovered. The separating resin and eluent are carefully chosen so that the eluent inherently has a low background conductivity. Anion chromatography is described in Sections III and IV. Selectivity data for the low-capacity resins used in anion chromatography is presented in Section V. It seemed possible to develop an analogous method for cations,- Finding an eluent of a low enough background conductivity proved to be a difficult problem. Cation chromatography was finally developed by using eluents that have a relatively high background conductance such as nitric acid. Sample cations appear as negative peaks beneath the background signal. Cation chromatography is described in Section VI. 5 SECTION I. EFFECT OF CAPACITY ON THE BEHAVIOR OF ANION-EXCHANGE RESINS INTRODUCTION It would be useful to be able to predict the effect of resin capacity on the behavior of ion-exchange resins, if capacity is to be used as a variable in ion-exchange chromatography.