tailieunhanh - Introduction to Modern Liquid Chromatography, Third Edition part 40

Introduction to Modern Liquid Chromatography, Third Edition part 40. 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. . | 346 IONIC SAMPLES REVERSED-PHASE ION-PAIR AND ION-EXCHANGE CHROMATOGRAPHY 0 2 4 Time min b 6 ACN II 4 A n 5 0 2 4 6 Time min Figure Solvent-type selectivity in the IPC separation of a catechol amine sample. Sample 1 noradrenaline 2 adrenaline 3 octopamine 4 3 4-dihydroxyphenylalanine 5 dopamine 6 isoprenol 7 tyrosine. Conditions 150 x Cig column 5-pm particles phosphate buffer plus 2-mM octane sulfonate IPC reagent 25 C 1 mL min. Adapted from 50 . Summary Developing an ll C separation can mroceed as foaiows 1. sekct initial conditions for RPC separation Section 2. vary B as in RPC in order to determine a value for an appropriate retention range . 1 k 10 3. varypHrnorderto tentalively idamtilyviurous peaksin the chromatogram as acidic basic or neutral unless peak identities are known by injecting standards- 4. at somestage offuraher RPCmethaddeve mena eunaiderthepoasibk value of odiieedfor h seporation Section 5. if IPC septeaekn isehoren chooseatffC reagentanaiis rnmel eonceinyn-tion as dccribed Vi Se ei . A prior khoer a rh of the composition of the sample or previous experiments wherepH isvaried iadip3 shouldinaicrtedhechoke afiirhyr a sulfonate la iree dedfr Incrtosingthe een onefr cidic solutes or a quaternary ammpgmm ide iae deiiv ae eatiomo soiuteel. eitevnatively for basic soletes aehasirope canae used as IPC reagent to increase their retention. 6. optimize relative retention iselecaiairy Siniultaiieouechaiigetin B vnd d repiPeiLe e ate expevtee id avhighly effective. Faefurthee eaaaaet ic seievtidity moVikiphaeepH udihe IPC reagent collccsirsrii sll cvnbe . htgs. e-ldt. IyanaCdikocvi change in seketiaity is needed unlikely vary other separation conditions listed atthebeampingofdection . . . ION-PAIR CHROMATOGRAPHY IPC 347 7. vary column conditions for further improvements in either resolution or run time Section Special Problems The separation of ionic samples by .

TÀI LIỆU LIÊN QUAN
TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.