The LC

What is LC/MS?

LC/MS stands for Liquid Chromatography/Mass Spectrometry. It refers to the combination of liquid chromatographic separation with mass spectrometric detection. The combination of these two powerful techniques gives the chemical analyst the ability to analyze virtually any molecular species; including, thermally labile, non-volatile, and high molecular weight species. It has been said that over 80% of known organic species are amenable to separation with liquid chromatography.(1) Mass spectrometry is capable of providing structure, molecular weight, empirical formula, and quantitative information about a specific analyte.

What is LC/MS?

The bird and fish metaphor, first described by Patrick Arpino (2) depicts love between totally incompatible species. Mass spectrometry, represented by the bird, is a powerful detection technique for gas-phase ions. Liquid Chromatography, represented by the fish, is a liquid-phase separation technique. Liquids are incompatible with operating conditions of the mass spectrometer, and gases are incompatible with the operation of the liquid chromatography. To stretch this metaphor, we can refer to interfacing between liquid chromatography as the "match-maker" between these star-crossed lovers.

1) Snyder, L.R, and, Kirkland , J.J., Introduction to Modern Liquid Chromatography. Wiley: New York (1991). This often quoted ratio has been a major justification for development of LC/MS over the past 20 years.

2) Arpino, Patrick J. Trying to arrange a difficult marriage: A report on the workshop on liquid chromatography mass spectrometry, held in Montreux, Switzerland, 22-23 October 1981, Biological Mass Spectrometry, Volume 9, Issue 4, Date: April 1982, Pages: 176-180.

Why is LC/MS important?

Provides unambiguous compound identity
Provides sensitive response to most analytes
Provides compound class information
Provides compound structure
Provides sequence information
Provides molecular weight information
Provides the five Ss
- Speed
- Selectivity
- Specificity
- Sensitivity
- $...Low Cost per Information Content

Who uses LC/MS?

Drug Discovery

Clinical Analysts

Proteomics

Forensic Chemists

Drug Metabolism

Environmental Chemists

Diagnostics......