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Biomedical subjects

H Lord

Publications and source records attributed to H Lord.

4 recordsLinked to original sources
PubMed2000

Microextraction of drugs.

This review will attempt to provide an overview as well as a theoretical and practical understanding of the use of microextraction technologies for drug analysis. The majority of the published reports to date focus on the use of fibre solid-phase microextraction and so the review is significantly focused on this technology. Other areas of microextraction such as single drop and solvent film microextraction are also described. Where there are insufficient examples in the literature to illustrate important concepts, examples of non-drug analyses are presented. The review is intended for readers new to the field of microextraction or its use in drug extraction, but also provides an overview of the most recent advances in the field which may be of interest to more experienced users. Particular emphasis is placed on the effect various sample matrices have on extraction characteristics.

Adsorption↗
PubMed2000

Evolution of solid-phase microextraction technology.

The main objective of this contribution is to describe the development of the concepts, techniques and devices associated with solid-phase microextraction, as a response to the evolution of understanding of the fundamental principles behind this technique. The discussion begins with an historical perspective on the very early work conduced almost a decade ago. As new fundamental understanding about the functioning of the technology developed, new ways of constructing and using the SPME devices evolved.

Chromatography, Liquid↗
PubMedDate not supplied

Automated in-tube solid-phase microextraction coupled with liquid chromatography-electrospray ionization mass spectrometry for the determination of selected benzodiazepines.

A simple, rapid, and sensitive method, which allowed us to simultaneously determine seven benzodiazepines (diazepam, nordiazepam, temazepam, oxazepam, 7-aminoflunitrazepam, N-desmethylflunitrazepam, and clonazepam) in buffer solution and in urine and serum samples, was investigated by automated in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). In-tube SPME, in which the analytes were extracted from the sample directly into an open tubular capillary column by repeated draw/eject cycles of sample solution, is an extraction technique for organic compounds in aqueous samples. The separation of benzodiazepines was carried out under ion-suppressed reversed-phase conditions by using methanol/50mM ammonium acetate in water (60:40) as a mobile phase with a Supelco LC-18 column. The optimal extraction condition was 10 draw/eject cycles of 30 mL of sample in 100mM Tris-HCl (pH 8.5) at a flow rate of 0.3 mL/min using a piece of 60-cm length Supelco-Q plot capillary column as the extraction capillary. The quantitative study was explored by operating in selected-ion monitoring (SIM) mode. The calibration curves were linear in the range from 0.5 ng/mL or 2 ng/mL to 500 ng/mL. The detection limits were from 0.02 ng/mL to 2 ng/mL. At the optimized capillary and fragmentor voltages, the characteristic ions for each compound clearly showed up in the spectra and it is possible to use the LC-MS to identify these compounds. The method was applied to the analysis of biological samples without interfering peaks. However, the recoveries for some of the compounds in serum samples need to be further improved.

Benzodiazepines↗