Five adrenolytic drugs have been analyzed by liquid chromatography-mass spectrometry (LC-MS). Samples were prepared by solid-phase microextraction (SPME) using polypyrrole fibers coated on stainless steel support as an adsorbent for the drugs. Adsorption efficiencies were 95% and were close for all the drugs investigated. Relative standard deviations (RSD), calculated for samples prepared in standard solutions, were in the range 2.5-13%, however RSD values for the drugs in human plasma were 2.5-4.5%. Using LC-MS the limit of detection (LOD) and the limit of quantification (LOQ) were in the ranges 0.11-0.18 and 0.39-0.54 ng mL(-1), respectively, for the five drugs.
[Show abstract][Hide abstract] ABSTRACT: Biomedical analyses of drugs, metabolites, poisons, environmental and occupational pollutants, disease biomarkers and endogenous substances in body fluids and tissues are important in the development of new drugs, therapeutic monitoring, forensic toxicology, patient diagnosis, and biomonitoring of human exposure to hazardous chemicals. In these analyses, sample preparation is essential for isolation of desired components from complex biological matrices and greatly influences their reliable and accurate determination. Solid-phase microextraction (SPME) is an effective sample preparation technique that has enabled miniaturization, automation and high-throughput performance. The use of SPME has reduced assay times, as well as the costs of solvents and disposal. This review focuses on recent advances in novel SPME techniques, including fiber SPME and in-tube SPME, in biomedical analysis. We also summarize the applications of these techniques to pharmacotherapeutic, forensic, and diagnostic studies, and to determinations of environmental and occupational exposure.
Journal of pharmaceutical and biomedical analysis 04/2011; 54(5):926-50. DOI:10.1016/j.jpba.2010.12.010 · 2.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A method has been devised for analysis of the residual gas content of small tetrodes or pentodes. In contrast to other methods which have been reported, the gas content of the tube being studied is not changed markedly by the analysis; analyses may be made repeatedly as the tube is operated, and moderately low pressures (1 × 10<sup>-10</sup>mm Hg) and small quantities (10<sup>-9</sup>cc mm) can be detected. A 90-degree sector magnetic analyzer with a 3-cm radius of curvature and 30-mil slits (resolution 1:20) is sealed to the tube to be analyzed prior to pumping. The analyzer is made of Corning 0120 glass with a conductive lining. The tube being tested serves as an ion source, avoiding the complications of a second hot filament. The device has been calibrated by comparison with known gases on a vacuum station. This method has been applied to study the gas content of the M1941 experimental pentode intended for applications which require extreme life and reliability. The normal gas pressure in this tube, after trolley pumping and 100 hours aging, is about 1 × 10<sup>-9</sup>mm Hg, predominately He, H 2 , and CO. When no getters are used, the partial pressures of H 2 and CO are higher, perhaps 1 × 10<sup>-8</sup>mm Hg. When titanium-alloy anodes are used in tubes without getters, the partial pressure of hydrogen is much higher, up to 1 × 10<sup>-6</sup>mm Hg. A number of these tubes have been followed for over 10,000 hours. Concurrent studies of the cathode emission have shown it to be markedly influenced by small partial pressures of hydrogen when pure nickel cathode cores are used. Hydrogen is very effective in raising the emission, but the emission falls quickly as the hydrogen pressure is reduced. At least part of the improved cathode performance observed in tubes with titanium anodes must be attributed to the increased hydrogen pressure which accompanies the use of titanium anodes. These data on hydrogen with pure nickel s-
hould not be extrapolated arbitrarily to active cathodes.
IRE Transactions on Electron Devices 04/1962; 8(2-9):190 - 196. DOI:10.1109/T-ED.1962.14969
[Show abstract][Hide abstract] ABSTRACT: In this study, polypyrrole (PPy) and polythiophene (PTh) SPME coatings and their ability to extract selected adrenolytic drugs with different physico-chemical properties from standard solutions and human plasma samples were evaluated. In measurements metoprolol, oxprenolol, mexiletine, propranolol, and propaphenon were investigated. The main parameters such as extraction time, desorption conditions and pH influence were examined. Inter-day precisions were in range 0.1-2.0%, 1.1-2.9%, 1.3-2.6%, 0.1-2.6% and 0.3-2.1% for metoprolol, oxprenolol, mexiletine, propranolol and propaphenon, respectively. Accuracies were less than 15%, which was evaluated by analyzing preparation samples of five replicates. The method was successfully applied to human plasma samples spiked with selected adrenolytic drugs. The method was linear in the concentration range from 1 to 10microg/ml for all of studied adrenolytic drugs using human plasma samples. The PTh-SPME coating displayed higher extraction efficiency towards the target analytes in comparison to PPy-SPME. The reproducibility of the extraction using polypyrrole and polythiophene fibers was confirmed by variation coefficients lower than 8% and 3%, respectively.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 08/2010; 878(24):2226-34. DOI:10.1016/j.jchromb.2010.06.033 · 2.73 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.