Sunscreen analysis: A critical survey on UV filters determination

A high-performance liquid chromatographic method with diode-array detection (HPLC/DAD) for systematic toxicological analysis of human blood or plasma samples is presented. After single-step liquid/liquid extraction at pH 9.5 using chloroform/2-propanol/n-heptane (60:14:26, v/v/v), the drugs elute isocratically from a NovaPak C18 (Waters) 4-micrometers column (300 mm x 3.9 mm, i.d.) at 30 degrees C, with methanol/tetrahydrofuran/pH 2.6 phosphate buffer (65:5:30, v/v/v) as the mobile phase (flow rate 0.8 mL/min). Full UV spectra from 200 to 400 nm (resolution 1.3 nm) are recorded on-line during the 20 min chromatographic run. Solute identification may be automatically performed by comparison of analytical data (retention times and UV spectra) with references of 311 pharmaceuticals, toxicants and drugs of abuse stored in a computerized library. The method is simple, rapid, relatively inexpensive and highly specific. The previously reported applications of HPLC/DAD technology to drug screening are reviewed, and the interests and limitations of the method are discussed in the light of this literature.

Systematic Toxicological Analysis Using HPLC/DAD

Use of high-performance liquid chromatography with photodiode-array uv detection for the creation of a 600-compound library. application to forensic toxicology

Perhaps the most consistent trend in the development of high-performance liquid chromatography (HPLC) since its inception in the 1960s has been the continuing reach for ever faster analyses. The pioneering work of Knox, Horvath, Halasz, and Guiochon set forth a theoretical framework that was used early on to improve the speed of HPLC, primarily through the commercialization of smaller and smaller particles. Over the past decade, approaches to improving the speed of HPLC have become more diverse, and now practitioners of HPLC are faced with the difficult task of deciding which of these approaches will lead them to the fastest analysis for their application. Digesting the rich literature on the optimization of HPLC is a difficult task in itself, which is further complicated by contradictory marketing messages from competing commercial outlets for HPLC technology. In this perspectives article we provide an overview of the theoretical and practical aspects of the principal modern approaches to improving the speed of HPLC. We present a straightforward theoretical basis, informed by decades of literature on the problem of optimization, that is useful for comparing different technologies for improving the speed of HPLC. Through mindful optimization of conditions, high-performance separations on the subminute timescale are now possible and becoming increasingly common under both isocratic and gradient elution conditions. Certainly the continued development of ultrafast separations will play an important role in the development of two-dimensional HPLC separations. Despite the relatively long history of HPLC as an analytical technique, there is no sign of a slow-down in the development of novel HPLC technologies.

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Perspectives on recent advances in the speed of high-performance liquid chromatography.

The non-volatile, water-soluble constituents of black tea were studied by using reversed-phase HPLC with a photodiode-array detector, using a linear gradient developed for this purpose. The data generated by this detector from one injection of a black tea liquor allowed information on the nature and purity of the constituents to be obtained. The following constituents were identified by the spectral data and the retention times given by reference compounds: caffeine, theobromine, (−)-epicatechin gallate, (−)- epigallocatechin gallate, gallic acid, chlorogenic acid (5-O-caffeoylquinic acid), p-coumaroylquinic acid, quercetin 3-glucoside, quercetin 3-rhamnosylglucoside, kaempferol 3-rhamnosylglucoside, and theaflavin digallate. Other peaks were classified by spectral data, but without reference compounds conclusive assignments could not be made. Finally, a group of peaks could be classified as coloured phenolic pigments, and tentatively assigned as thearubigins.

Terry Sheehan

Papers

Recent Developments in Multichannel, Photodiode-Array, Optical LC Detection

Enhancement of detection sensitivity and cleanup selectivity for tobramycin through pre-column derivatization.

Determination of compound identity by group type and class using diode-array detection in high-performance liquid chromatography

Faster quantitative evaluation of high-performance liquid chromatography-ultraviolet diode-array data by multicomponent analysis

Chiral separation and detection enhancement of propranolol using automated pre-column derivatization.