Advantages of LC-MS over GC MS and other technologies

Article 2

LCMS analysis of the Liquid Chromatography-Mass Spectrometry analysis combines the Liquid Chromatography’s separation ability and the mass spectrometry detection ability. The coupling of Liquid Chromatography and Mass Spectrometry is used for quantifications of biopharmaceuticals. Right from accuracy to precision, the LCMS unit offers heaps of advantages – better selectivity, generic applicability, etc.

Liquid Chromatography –

LC or liquid chromatography application is divided into two different categories – qualitative analysis and quantitation. Qualitative analysis is defined as the consistency between the sample and its target component within a defined peak time. On the other hand, quantitation is accomplished according to the standard curve derived by injecting different standard concentrations. Although LC is useful for separating complex samples, obtaining structural information about the sample becomes quite difficult.

Mass Spectrometry –

Mass Spectrometry forms an integral part of the LC MS analysis due to its high sensitivity, high selectivity, and ability to provide relevant information, including the structural characterization of the pharmaceutical drug product and its relative molecular mass.

LCMS analysis –

Coupling of separating the ability of the LC with the detection ability of the MS system, the LC MS analysis helps in speculating the compound structure, thereby focusing on both the qualitative and quantitative analysis of the compound under analysis.

Advantages of LCMS analysis –

LCMS is advantageous in the following aspects –

Pharmacokinetics –

For the pharmacokinetic analysis of small molecules, LCMS is typically employed in its bioanalysis process. The primary advantage of using the LCMS instrument is that it is highly sensitive and specific compared to UV detectors, which are routinely employed in the UV detection units.

Peptide Mapping –

LCMS method can be used for the verification of the amino acid sequence of a therapeutic protein. This process typically involves sample digestion using a series of peptidases and their fragments, which can be smoothly run over LCMS to verify the expected mass of individual fragments.

Quality Control –

LCMS is a convenient method for compound identity testing with the use of a reference standard. In this way, the LCMS helps in determining the purity of both the drug substance and its finished product.

Identification of the Post-translational Modification –

The analysis of both the glycosylation and post-translational modification of proteins employs LCMS.

In comparison with other ligand binding assays, LC MS methods offer several critical advantages such as more extensive linear dynamic ranges, higher precision and accuracy, and possibilities of the application of wide ranges of internal standards. Furthermore, it has the benefit of accomplishing multiple sample bioanalysis simultaneously. The best thing here is that there is no need for immunological reagents to be used here. The use of immunological reagents can introduce batch-to-batch variability, thereby making the result comparison a more complicated process to accomplish.

Concerning the LC MS method disadvantages, the method has high analysis or operational cost, limited sample throughput. It offers less favorable sensitivity for the pharmaceutical drug concentration. Additionally, with LC MS analysis, there is a loss of the 3D structure of protein analyte of interest. Furthermore, it offers difficulty in relating the bioanalytical principle to the complex protein structure, which facilitates the determination of the pharmacological activity.