液相層析質譜分析 LC-MS Method development and Analyte Identification 授課教師:賴滄海教授 授課教師:賴滄海教授
Ionization ESI ESI Sonic Spray I Sonic Spray I APCI APCI APPI APPI APLI APLI
Ion Separation Ion Separation Mass range Mass range Scan speed Scan speed Mass resolution Mass resolution Mass accuracy Mass accuracy
Mass Accuracy An unknown compound appears at m/z in the positive ion mode. An unknown compound appears at m/z in the positive ion mode. The mass accuracy of the spectrometer is 2-5 ppm. The mass accuracy of the spectrometer is 2-5 ppm.
Assuming it contains C.H.O.N.P.S. F.Cl.Br
Mass Analyzer Mass Analyzer Quadrupole Quadrupole Ion trap Ion trap Linear ion Trap Linear ion Trap Time of flight Time of flight
Steps in the quantification of drugs Sampling Sampling Sample preparation Sample preparation Separation Separation Detection Detection Data analysis Data analysis
General Considerations What to measure ( drug/metabolites) What to measure ( drug/metabolites) Select matrix (blood,serum,plasma,tissue) Select matrix (blood,serum,plasma,tissue) Sample limitations (volume,sample size) Sample limitations (volume,sample size) Linear range Linear range Lower limit of quantification Lower limit of quantification Internal standard Internal standard
Problems with Deuterated Is [ 13 C,D 3 ] rofecoxib exchange with Hydrogen atoms on water molecular [J Chromatogr B 2002;767: ]
Positive identification with GC-MS(SIM) 1. 3 ions 2. Retention time the same as standards 3. Ion ratio correct 4. S/N > 3 5. Sample processed to remove interferences
Aspects to be considered when setting up LC-MS procedures 1. Influence of the mobile phase 2. Influence of sodium and potassium on the formation of adducts 3. Influence of the curtain gas flow 4. Reproducibility of mass spectra 5. Influence of ion suppression 6. GC-MS data to verify LC-MS results
Mass spectrometry Ionization Ionization Matrix effect Matrix effect Full scan Full scan MRM MRM
Figure 2.5 The influence of collision energy on the fragmentation of tacrolimus at (a)10, (b)20,(c)30,(d)40 and (e)50eV.
Sample preparation Sample preparation Sample dilution and protein precipitation Sample dilution and protein precipitation Liquid-liquid extraction Liquid-liquid extraction Solid phase extraction Solid phase extraction Two dimensional chromatography (column switching) Two dimensional chromatography (column switching)