Development of a fully automated toxicological LC-MSn screening system in urine using online extraction with turbulent flow chromatography

In clinical toxicology, fast and specific methods are necessary for the screening of different classes of drugs. Therefore, an online extraction high-performance liquid chromatography coupled to mass spectrometry (LC-MSn) screening method using a MS2 and MS3 spectral library for the identification of xenobiotic substances has been developed and validated. Samples were run twice, once native and once after enzymatic hydrolysis. Internal standards and buffer were added to the urine samples. Following centrifugation, the supernatant was injected into the system. Extraction was performed by online turbulent flow chromatography. The chromatographic separation was achieved using a Phenyl/Hexyl column. For detection, a linear ion trap, equipped with an APCI interface, was used and the different compounds were identified using a MS2 and MS3 spectral library containing 356 compounds. The turnaround time to report the results of the screening including hydrolysis was approximately 2h. About 92% of the 356 substances could be identified with a limit of identification below 100ng/ml. The recovery and matrix effect experiments showed suitable results, and in six drug-free urine samples of healthy volunteers analyzed for selectivity, no substances have been identified. Carryover could be well controlled, and the method had a good reproducibility. The comparison of the results of 103 real patient urine samples showed a good agreement between the existing GC-MS and LC-MS methods with offline extraction and the new online extraction LC-MSn screening method. The presented method allows a fast and sensitive analysis of a broad range of compound

Мобильные установки для ручной и механизированной лазерной сварки и обработки металлов (Обзор)

Представлен обзор мобильных установок для ручной и механизированной лазерной сварки и обработки конструкционных металлов. Даны описания и краткие технические характеристики установки для очистки металлических поверхностей от краски и других загрязнений, переносных аппаратов для механизированной лазерной сварки стыковых и нахлесточных соединений, установки дл лазерной обработки и наплавки.The paper presents a review of mobile units for manual and mechanized laser welding and treatment of metals. Description and brief specification of a unit for cleaning metallic surfaces from paint and other contamination, portable units for mechanized laser welding of butt and overlap joints and of a laser surfacing unit are given

Determination Of Tributyltin In The Marine-Environment

Tributyltin (TBT) is a biocide used in antifouling paints to protect hulls from nuisance organisms such as barnacles, worms and algae. The use of TBT paints has increased over the past decade due to its effectiveness as an antifoulant which is related to its toxicity. Water concentrations of less than 100 ng L- have been shown to harm some aquatic species in laboratory tests and observations in the natural environment indicate that levels below 10 ng L- may be harmful. Tributyltin is bioconcentrated by many species to levels of one thousand, or more, times ambient water concentrations. Sediment-water partitioning coefficients for TBT of 100-10,000 have been reported [1]. The extreme toxicity of TBT challenges the analytical chemist to accurately and precisely determine ambient TBT concentrations in water at or below I ng L\u27 and in sediments and tissue at concentrations ranging from pLg kg-\u27 to mg kg-\u27

Tributyltin in whole water and sediment collected from marinas and the Hampton Roads area in the southern Chesapeake Bay : a final report

This report presents data gathered in a program designed to monitor tributyltin (TBT) levels in water and sediment from areas in the southern Chesapeake Bay which experience high boating activities. The concentrations reported will hopefully give an insight into the extent and magnitude of TBT contamination in these areas

Live-imaging of Mitochondrial System in Cultured Astrocytes.

While much attention has been given to mitochondrial alterations at the neuronal level, recent evidence demonstrates that mitochondrial dynamics and function in astrocytes are implicated in cognition. This article describes the method for time-lapse imaging of astrocyte cultures equipped with a mitochondrial biosensor: MitoTimer. MitoTimer is a powerful and unique tool to assess mitochondrial dynamics, mobility, morphology, biogenesis, and redox state. Here, the different procedures for culture, image acquisitions, and subsequent mitochondrial analysis are presented

Some implications of lateritic weathering on geochemical prospecting -two Brazilian examples

ABSTRACT Parisot

Development of a fully automated toxicological LC-MS(n) screening system in urine using online extraction with turbulent flow chromatography

In clinical toxicology, fast and specific methods are necessary for the screening of different classes of drugs. Therefore, an online extraction high-performance liquid chromatography coupled to mass spectrometry (LC-MS(n)) screening method using a MS(2) and MS(3) spectral library for the identification of xenobiotic substances has been developed and validated. Samples were run twice, once native and once after enzymatic hydrolysis. Internal standards and buffer were added to the urine samples. Following centrifugation, the supernatant was injected into the system. Extraction was performed by online turbulent flow chromatography. The chromatographic separation was achieved using a Phenyl/Hexyl column. For detection, a linear ion trap, equipped with an APCI interface, was used and the different compounds were identified using a MS(2) and MS(3) spectral library containing 356 compounds. The turnaround time to report the results of the screening including hydrolysis was approximately 2 h. About 92% of the 356 substances could be identified with a limit of identification below 100 ng/ml. The recovery and matrix effect experiments showed suitable results, and in six drug-free urine samples of healthy volunteers analyzed for selectivity, no substances have been identified. Carryover could be well controlled, and the method had a good reproducibility. The comparison of the results of 103 real patient urine samples showed a good agreement between the existing GC-MS and LC-MS methods with offline extraction and the new online extraction LC-MS(n) screening method. The presented method allows a fast and sensitive analysis of a broad range of compounds

Organotin levels in the Ria Formosa lagoon, Portugal

Organotin concentrations were measured in water, sediments and clams (Ruditapes decussatus) from 11 sites in the Ria Formosa lagoon, Portugal, in 1992-93. Results showed a marked spatial pattern of tributyltin (TBT) and dibutyltin concentrations. The highest organotin concentrations were observed at Olhao (site 5), where the most important fishing harbour of the Southern coast of Portugal is located. Results indicated that fishing vessels, moored in the harbour at Olhao (site 5), were the major source of organotin contamination to the lagoon. No significant seasonal trend was observed, suggesting a continuous input of organotin compounds throughout the year. In several areas of the lagoon the TBT burdens in R. decussatus could have deleterious developmental effectsPraxis/BD/1424/91-1G. BOATS priject 8Mas2-CT-0099)info:eu-repo/semantics/publishedVersio