A critical evaluation of high performance liquid chromatography‐electrospray ionisation‐mass spectrometry and capillary electrophoresis‐ electrospray‐mass spectrometry for the detection and determination of small molecules of significance in clinical and forensic science

Abstract

A critical review of applications for the period 2000-2003, taken from the Web of Knowledge database, of the techniques high performance liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS) and capillary electrophoresis-electrospray ionisation-mass spectrometry (CE-ESI-MS) to the detection and determination of small molecules of significance in clinical and forensic science is presented. The molecules of mass less than 500 Da are chosen according to selected structural classes in which they give ESI signals primarily as [M+H](+) ions although other ions such as [M-H](-), [M+Na](+) and [M+NH(4)](+) are also reported. The structural classes are drugs with amine-containing side chains, drugs with N-containing saturated ring structures, 1,4-benzodiazepines, carbohydrates, benzimidazoles, other heterocycles, sulphonylureas, anthracyclines, sulphonamides, penicillins, cephalosporins, tetracyclines, nitrocatechols, steroids, flavonoids, oxazaphosphorines, cannabinols, and miscellaneous molecules. Details are given on the fragmentations, where available, that these ionic species exhibit in-source and in ion-trap, triple quadrupole and time-of-flight mass spectrometers. The review then gives a critical evaluation of these recent HPLC-ESI-MS and CE-ESI-MS analytical methods for the detection and determination of small molecules of clinical and forensic significance. Analytical information on, for example, sample concentration techniques, HPLC and CE separation conditions, recoveries from biological media and limits of detection (LODs) are provided.

A Study of Electrospray Ionization Emitters with Differing Geometries with Respect to Flow Rate and Electrospray Voltage

“…Similar to their larger scale counter parts microfluidic separations and sample transport can be divided into 2 categories: (1) electrokinetic and (2) hydrodynamic or pressure driven mass transport. Hydrodynamic separations, such as HPLC, have been readily integrated into capillary and microchip platforms and their widespread use has been adopted [7,56,67]. EOF originates from the movement of the diffuse layer in an electric field and has the advantage of being able to provide plug-like flow that reduces band broadening greatly compared with pressure driven systems.…”

Capillary Electrophoresis in Determination of Low Molecular Mass Organic Acids

“…CE-MS combines the advantage of both techniques, so that quantitative and qualitative information based on migration time, in combination with molecular masses and/or fragmentation patterns can be obtained in one analysis. Currently, electro-spray ionization (ESI) serves as the most common interface between capillary electrophoresis and MS, as it can produce ions directly from liquids at atmospheric pressure, and provide sensitivity and selectivity for a wide range of analytes [16], [23].…”

18 Coupling CE and microchip-based devices with mass spectrometry

“…On-line coupling of CE with MS has generated a wealth of data in bioanalytical (''life science''), 23,1422151 pharmaceutical, 1522156 forensic, 157 and environmental 1582160 domains, and was the subject of a number of comprehensive reviews. 14,15,161 The reader is thus referred to these sources for a systematic coverage of the field and a more extensive discussion of CE2MS applications than can be given in this context.…”