LIQUID CHROMATOGRAPHY – MASS SPECTROSCOPY (LC-MS)

Presented by
Md Akbar Siddiq Khan

M.Pharm

Nizam College Of Pharmacy

Hyderabad – A.P

What is LC-MS?

It is the combination of liquid chromatography and the mass spectrometry.

• In LC-MS we are removing the detector from the column of LC and fitting the column to interface of MS.

• In the most of the cases the interface used in LC-MS are ionization source.

PROBLEMS IN COMBINING HPLC AND MS

HPLC

• Liquid phase operation

• 25 – 50 deg. C

• No mass range limitations

• Inorganic buffers

• 1 ml/min eluent flow is equivalent to 500 ml/min of gas

MS

• Vacuum operation

• 200 – 300 deg. C

• Up to 4000 Da for quadrupole MS

• Requires volatile buffers

• Accepts 10 ml/min gas flow

PARTS OF LC-MS

 Two key components in this process are the ion source, which generates the ions, and the mass analyzer, which sorts the ions.

Several different types of ion sources are commonly used for LC/MS.

MOBILE PHASE:-

The mobile phase is the solvent that moves the solute through out column.

 General requirements:-

(1)low cost, uv transperancy,high purity.

(2)low viscosity, low toxicity, non flammability.

(3)non corrosive to LC system component.

 Solvent strength and selectivity:- it is the ability of solvent to elute solutes from a column.

COLUMN:-

 Column type:-

 Specialized mode:-

 The use of di-functional or tri-functional silanes to create bonded groups with two or three attachement points leading to phases with higher stability in low or higher pH and lower bleed for LCMS

 Most widely used columns for LCMS are:-

(1) fast LC column. the use of short column. (15-50mm)

(2) Micro LC column. the use of large column. ( 20 150mm)

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