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Dushyant Patel LC-MS/MS Method

S.K.P.C.P.E.R., Kherva 29 M .Pharm. Thesis

Recently different types of hybrid mass analyzers are developed for specific

application for e.g. quadrupole-linear trap, quadrupole-time-of-flight; ion trap-time-of-

flight.

¾ In triple quadrupole instruments mass analysis is performed in the first and third

quadrupole while the second quadrupole is used as collision cell in the RF only mode.

Different scan modes are available like product ion scan mode- for structure elucidation,

parent ion scan mode and neutral scan mode -for screening, selected ion monitoring

(SIM) and selected reaction monitoring (SRM) scan mode for quantitative analysis. The

tandem mass spectrometry is a very specific and selective technique for quantitation of

drug in different matrix.

4.1.3 LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

(LC-MS/MS):

¾ By putting a separating chemistry from an HPLC in front of a specialized detector such

as the mass spectrometer, one has a true multidimensional analytical technique that

raises the level of the confidence of what you are looking at. Combining HPLC and

MS offer the possibility of taking advantage of both HPLC as a powerful separation

technique and MS as a powerful and sensitive detection and identification technique.

HPLC chromatographic peaks may contain unresolved components that non-specific

detectors cannot differentiate. This coupled with the need for more sensitive and

specific detector for HPLC has generated considerable interest in the development of

routine liquid chromatography-mass spectrometry (LC-MS)

. The mass spectrometer

can be considered as a universal, selective and specific detector depending on

selective mode of operation. An HPLC followed by mass spectrometric detection

enables the quantification of therapeutically relevant drug concentration (µg/ml or ng/ml

range) in small volume of biological samples and determinations of the chemical

structures of biotransformation. The principle advantage of HPLC separation followed

by the MS detection is that analyte molecular weight is identified by both

chromatographic retention time and by molecular weight & fragmentation pattern. Two-

dimensional separation is particularly important for the analysis of complex biological

samples.

¾ The coupling between LC & MS has not been straight forward since the normal operation

condition of both HPLC and MS are different high pressure/ high vacuum, low

temperature/high temperature, liquid phase/ gas phase, high flow/low flow to achieve

and to cope with these problem different LC-MS interface have been developed. The

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Samsung RT34M Manuale Utente Pagina 41