tailieunhanh - Introduction to Modern Liquid Chromatography, Third Edition part 39

Introduction to Modern Liquid Chromatography, Third Edition part 39. High-performance liquid chromatography (HPLC) is today the leading technique for chemical analysis and related applications, with an ability to separate, analyze, and/or purify virtually any sample. Snyder and Kirkland's Introduction to Modern Liquid Chromatography has long represented the premier reference to HPLC. This Third Edition, with John Dolan as added coauthor, addresses important improvements in columns and equipment, as well as major advances in our understanding of HPLC separation, our ability to solve problems that were troublesome in the past, and the application of HPLC for new kinds of samples. . | 336 IONIC SAMPLES REVERSED-PHASE ION-PAIR AND ION-EXCHANGE CHROMATOGRAPHY sorbed TBA . For examples of these generalizations see the discussion of Figure in the following section. Ion-Pair Reagent Concentration and Type It is possibieto continuously vary thenature ofretention from Rl o retention as in Figure toIPC retention as in Figure by varying the concentration of the IPC rxagernid fhe anwiary phase. The concentration of the reagent in the stationary phase can be varied by changing its concentration in the mobile phase. Wewiiluse theexampleof toillustratethe effect of IPC reagent concentration untolute example oteeeobutetammuoiumahosphasr IPC reagent TBA is a turned initioliy witO o Cscolumn. Coveidor iprt tt ec equilibrium uptakpofTBA RPbytheftaiionatypOape toiiOcuniefoeTBA at the botrpm if P ir Ore statiuortophate R s is plotted ypvueut We conceittrationm aPe moOlleuhosup j thowonpa uononueP increase insty0onefyghasccBncenteoOoo to Rh mmcreates until the atatioeary phase becomes taturored witlr R wtOi no further ahacge in chncrnteation htR in the stations. phasa forfvrOiou ionrense io R m .Thr .0011 1 11 501 to typical of the uptakeottartAleos othuumolocAesOy o R00cohimn wpan Cfesceipie concentrationin Oie mobilo ynoscisinoreased senelUeUCtogmuie aPsocafiov Section onO hq. . Twopiltareoiplots vfiR io ccrsus R mase tBuwyinVigura curve for fEAC otida petOedcueveroc ietreetholammnniom TUn U Bacautr TBA is ttte moer Vrdrophoeicott0f ewntPC raagentr spe retsrnrd Cp Rirp stationary oOrtr morestronply andsaturpttt the oolomoatalywer covoentration of R in themobiie ion-aairing will deaend on the fractional saturation of thoctotioua. pirate and istecBto dependent the IFCeeaoeut concentraiionin the mnCik ahase aoV die hcOrophoblcity or1AnntiOBef tOelAC reagent. IOW eeagcnr CyerophpOioltypod retenripn will nrceeatefor an increase in the .