High-performance liquid chromatography operational sensitivity

The following table provides some comparative data for the selection and operation of the more common detectors applied to high-performance liquid chromatography.15 In general, the operational parameters provided are for optimized systems and represent the maximum obtainable in terms of sensitivity and linearity. In this table, the molar extinction coefficient is represented by s. 

A suitable method for the determination of pilocarpine (7) and its degradation products (8, 16,17) requires a technique with a high specificity and sensitivity that can operate under mild conditions. Many methods lack at least one of these requirements. High-performance liquid chromatography (HPLC) on a cation-exchange resin still suffers from some drawbacks (58,76,77). The use of these resins implies operating conditions (pH 9) where pilocarpine is known to undergo alkali-catalyzed hydrolysis, and the... 

A method that uses high performance liquid chromatography/ mass spectrometry (HPLC/MS) for the analysis of chlorinated phenoxyacid herbicides is described. During method development different techniques were used to increase both the sensitivity and the specificity of thermospray HPLC/MS for chlorinated acid herbicides. These included the operation of the instrument in the negative chemical ionization (NCI) mode initiated by discharge and the use of a wire-repeller in the ion source for efficient extraction of positive ions. Single quadrupole repeller-induced and multiple quadrupole collision activated dissociation (CAD) experiments were also performed to increase the structural information of the mass spectra. 

High-performance liquid chromatography (HPLC) techniques offer versatility with minimal sample preparation. Its specificity and sensitivity, relatively small sample requirements, and the ease of operation make HPLC a practical alternative to GLC. HPLC has also been adapted to the simultaneous quantification of a large variety of drugs and... 

Mass spectrometry (MS) is one of the most powerful detection techniques used in liquid-phase analyses,1 mainly due to the ease of interfacing with separation techniques such as capillary electrophoresis (CE)2,3 and high-performance liquid chromatography (HPLC).4 Due to its sensitivity and applicability to a wide variety of chemical and biochemical species, MS is also used for the analysis of (bio)chemical molecules processed in microfluidics devices.5,6 Electrospray ionization (ESI)7 10 is often used to transfer samples from microfluidics chips to a mass spectrometer, involving analyte ionization directly from solutions and operating at flow rates typically used in microfluidics devices.11 Due to its effectiveness, the use of chip-MS coupling has rapidly spread in many research areas with bioanalytical applications,12 such as the... 

With its different modes of operation, high-performance liquid chromatography (HPLC) is a most suitable technique for the separation of less volatile, polar, or even ionic analytes. HPLC separation provides a continuous eluent flow of typically up to 1 mL min which can easily be introduced into the nebuHser of a flame AAS system. The interface design generally is a critical factor, since it may induce additional peak broadening which reduces both sensitivity and resolution. 

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