tailieunhanh - Introduction to Modern Liquid Chromatography, Third Edition part 41

Introduction to Modern Liquid Chromatography, Third Edition part 41. 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. . | 356 IONIC SAMPLES REVERS ED-PHAS E ION-PAIR AND I ON-EXCH AN G E CH ROMATOG RAPHY 1 3 2 U4 6 8 O 2 4 6 8 10 12 Time min Figure 7-21 Separation of a mixture of carbohydrate standards by anion-exchange chromatography with amperometric detection. Sample 1 myo-iuositol 2 D-sorbitol 3 lactitol 4 L-fructose 5 rhamnose 6 D-galactose 7 D-glucosamine 8 D-glugose 9 D-mannose 10 D-fructose 11 D-ribose. Conditions 300 x 4-mm anion-exchange column 5- rm particles mobile phase aqueous 5-mM NaOH 1-mM Ba OAC 2 ambient temperature 1 mL min. Adapted from 68 . RPC ac .tuA 0 2 4 6 8 10 12 14 16 18 min Figure 7 22 Separation of a nitrogen-mustard mixture by RPC a versus mixed-mode IPC b . Sample a mixture of small hydrophilic amines. Conditions in 150 x Prime -sep 100 column 5-pm particles SIELC Technologies USA 40 acetonitrile buffer TFA mL min. Adapted from 70 . while better peakshapesforcompounds 9andl0are elsoohscrvcd. Another example of mixed-moeexeparationwith xcation-oxchange column PrimeSep SIELC hae been reportedto pirec unique enthoeyanin slution pattern for the analyst nf grape juice 710. a ttcrnthatfacditatos peak identification and quantitation. Retention in mixed-mode separations can be controlled by varying B pH and buffer or saitconcen-rateon. repaftt-eoexolcions eCntoffi-ct setertivstysn RPP cs IEC can beusedtavxeyselttiee 1 0 011. Mixsntmoneteparaponínse offcrsit niw tr tie plbbismofpoor -611 in RPC of retrain ttrongbrsee t-thceahre ce n oxn s canbe more ettnngly retained by h i i oicticntvh aie n i ebe pCargeC column iit i. An additional advantagenf mixeVemo0scolueent mtXesretpeetia eheir 1 1 loadtbilily lyr ionized saIaCe ana i 1 xoe A iir1tohns1n11trevirtually unique in being able to simultaneously seessaatminturee rl ement eatione zwitterioos sndnsutratt . A mixed-modecation-exehcnaeecfumnwhieV 11sspeciallestaXilsalowcHi wlule maintaining ecceptionai tificieocy wcs reptfted thortiyXefarediecretent bock was sent tooh1punlithet 74 . Cpmpatilox1ot