Liquid Chromatography-Mass Spectrometry LC-MS Analysis and LC-MS/MS: Application of LC/ESI-MS in In Forensic Sciences, Doping Test, Pharmacokinetics, Bioavailability and Bioequivalence study, Environmental, and Agrochemical and Pesticides Industry

Abstract

The technique of LC mass spectrometry is an analytical method that brings together the chromatographic separation of target compounds (or analytes) and the subsequent detection of those compounds based on their mass. In particular, the sensitivity, selectivity, and accuracy of liquid chromatography tandem triple-quadrupole mass spectrometry (LC-MS/MS) have led to the development of procedures that are optimal for detecting nanomolar or even picomolar quantities of a wide variety of analytes. These analytes include drugs, drug and food metabolites, biomarkers of disease progression or drug efficacy, pesticides, food contaminants, markers of ecosystem stability, and natural product extracts. These procedures have been widely utilised because of their unique combination of these characteristics. When it comes to liquid chromatographic separations, the specificity of mass spectrometry detection allows for greater flexibility and efficiency. In the event that quantitative selectivity can be established, the liquid chromatography separation becomes less important for LC/MS/MS than it is for HPLC/UV. This is due to the fact that MS/MS has the ability to detect molecules with differentiable products in a unique manner, even if the molecules co-elute. Simple chromatographic procedures are frequently sufficient for LC/MS/MS, whereas HPLC/UV necessitates complete separation in order to function well. As a consequence of this, the run times that can be achieved using LC/MS/MS can be significantly reduced, and accuracy and precision can be improved. The finest of both worlds is achieved here! Controlling the ionisation process is the most significant obstacle in the identification of multiple sclerosis. When it comes to the MS detector, issues with incomplete ionisation and interference might result in a lack of precision and accuracy. Altering the detection method, utilising a variety of ionisation techniques, utilising sample preparation solvents, utilising LC stationary phases (columns), or LC mobile phases, and utilising chromatographic separations through isocratic or gradient procedures are all potential solutions at your disposal. The time-of-flight MS, the ion capture MS, and other detection methods are also included in the list of other techniques. Electrospray ionisation (ESI), atmospheric pressure chemical ionisation (APCI), photoionization, and other specialised techniques are all examples of methodological approaches that fall under the category of source ionisation. The precision, accuracy, selectivity, and sensitivity of MS detection are all improved by the use of these one-of-a-kind approaches, which make use of various MS detector setups. Additionally, because it is necessary to minimise the introduction of non-volatile components to the MS source, the choices of LC buffer salts are restricted to volatile buffer systems (typically ammonium cations with formate or acetate anions). These buffer systems may offer limited buffering capacity at typical mobile phase pH levels.