Presentation on theme: "LC-MS Plus NMR Building And Confirming Modern Molecular Libraries Bob Albrecht Protasis Corporation."— Presentation transcript:
LC-MS Plus NMR Building And Confirming Modern Molecular Libraries Bob Albrecht Protasis Corporation
LC / Mass Spectrometry Alone First choice for compound identification Very sensitive and fast, but… Not enough information to elucidate novel compounds Often ambiguous verification Ionization problems complicate identification
CapNMR From Purified Fractions Simple –No tricky SPE method or LC solvents –No stop-flow –No HPLC solvent suppression –No re-shimming Inexpensive No interferences = easier elucidation Best NMR Sensitivity vs. online LC- NMR or LC-SPE-NMR Largest fraction capacity vs. LC- SPE-NMR (384+)
Micro-plate Fraction Collection CapNMR is designed for analytical-scale separations.
MS isn’t enough for novel structure determination, but… CapNMR Has The Power MS + 1D Proton NMR in deuterated solvent is often enough for verification, but when it isn’t… CapNMR enables full structure elucidation of unknowns –13C, 15N, HSQC, HMBC, HMQC, COSY, TOCSY, ROESY, NOESY without changing probes! One-Minute NMR keeps the system running non-stop
Chromatographic Purification Strategies Time / Volume UV MS MS + UV
Time / Volume Directed Purification Fractions can contain 2+ compounds Less mass of purified material Many fractions Collects everything
UV-Directed Purification More pure compound Few impure fractions Too many worthless fractions No chromaphore, no fraction
MS-Directed Purification Pure fractions MS picks valuable fractions “Worthless” fractions may actually have value Poor ionization can waste valuable fractions Unknown mass range a problem
MS + UV Purification Poor ionization, fractions still collected No chromaphore, fractions still colleted Mass range can screen-out unlikely hits NMR on fractions with interesting MS spectra
C 18 HPLC of extract from marine-derived Cephalosporium sp. DAD detection Bioactivity profile Workflow Example: Natural Products Dereplication Active Peak(s) John W Blunt, Department of Chemistry, University of Canterbury, Christchurch NEW ZEALAND 12
500 MHz 8 g in 6 L CD 3 OD PRESAT 1.5 min Recognisable features: 5 CH 3 groups, of which 1 methoxyl, 3 singlet CH 3 -C, 1 doublet CH 3 -C; 1 aldehyde 13 John W Blunt, Department of Chemistry, University of Canterbury, Christchurch NEW ZEALAND
Purification Scale UPLC™ (2.1x150mm 1.7 µ ) –< ~2 mg sample, plenty for MS (.1 µ g) + CapNMR (50 µ g) –Amazing chromatographic resolution –highest purity fractions –CapNMR on 2.5% of total fraction mass Analytical – (4.6x150mm 3-5 µ ) –< ~7mg sample –Good chromatographic resolution –CapNMR on 0.7% of total fraction mass Semi-Prep –50mg to grams of sample –Longer runs –Less resolution, more impure fractions –Typical for compound libraries –CapNMR on 0.1% of total fraction mass
Purification Scale-Down Saves Time and Money t ≈ $ ∆t + ∆$ = ∆productivity
Analytical Scale Chromatographic Resolution Matters There are three compounds under this peak. The MS sees them, but you will not get the purity you need for NMR elucidation.
But… Trade-Off With Sensitivity You still need to scale-down NMR to Elucidate the 0.1% fraction. A second analytical run resolves a poorly resolved semi-prep fraction.
One-Minute NMR Software Web / enabled Import Fraction Lists Run NMR Experiments Maintain NMR Quality Archive and Process Data Customizable
One-Minute NMR Manages Samples from Plates and Vials Interfaces with: People (Web, ) NMR LC-MS ACD/Labs OneMoon Custom Software Interfaces with: People (Web, ) NMR LC-MS ACD/Labs OneMoon Custom Software
CapNMR Specifically Designed for NMR of LC Peaks Excellent NMR Results from: 20 – 200µg samples 0.1% fraction for semi-prep 0.7% fraction for analytical scale 2.5% fraction for UPLC CapNMR TXI Runs all of your NMR experiments for structure elucidation without changing the probe! 1H, 13C, 15N, 1D, 2D: APT, INEPT, DEPT, NOE, COSY, RELAY, DQFCOSY, TQCOSY, TOCSY, HOMJ, NOESY, ROESY, INADEQUATE, PFG, gCOSY, gDQFCOS, HETCOR, HMQC, HSQC, HMBC, gHMBC, gHMQC, gHSQC… Dual flow cell now available!
Isolated Model Compound NMR 5 Model Compound Mixture –CapNMR at 600 MHz –64 Scans (4 minutes) –5 ug of 5 components Isolated proparacain Isolated proparacain CapNMR at 600 MHz CapNMR at 600 MHz 16 Scans (1 minute) 16 Scans (1 minute) 5 ug of 1 component on column 5 ug of 1 component on column Data Courtesy Novatia, LLC
Online LC-NMR vs. Fractionation + CapNMR On flow NMR NT=512 CAP-NMR of fraction C47 NT=16 MW 740 -> agl 286 Data Courtesy of Jean-Luc Wolfender Metabolomics University of Geneva, Switzerland
LC/UV/MS of the chromatogram used for micro-fractionation [M-H] - 739,3 477,5 445,6 740,8 421,6 216,2 741,8 506,6 446,7 921,7 313,3 775,8609,8 281,3 863,8593,7 922,9 738,8 253,3567,7 404,9387,6 776,8 468,5 364,9 957,7742,9 670,4 515,2650,8 832,2 902,0 997,5956,1 m/z 739 TIC UV (254nm) Data Courtesy of Jean-Luc Wolfender Metabolomics University of Geneva, Switzerland
Cap-NMR gCOSY spectrum of fraction C47 NT=1 NI=512 Time=12 min Data Courtesy of Jean-Luc Wolfender Metabolomics University of Geneva, Switzerland
Thanks John W Blunt, Department of Chemistry, University of Canterbury, Christchurch NEW ZEALAND Jean-Luc Wolfender, University of Geneva David Detlefsen, Novatia Protasis Corporation