Search results for " High pressure liquid"
showing 10 items of 705 documents
The metabolism of phenol and substituted phenols in zebra fish.
1987
1. The metabolism of five phenols in zebra fish was studied after uptake from the medium. The results showed no qualitative differences to other Cyprinid fish species, only the oxidation rate seemed to be lower. 2. Phenyl glucuronide, phenyl sulphate, and quinol sulphate were identified as metabolites of phenol. 3. Identified metabolites of 2-cresol were 2-cresyl glucuronide, 2-cresyl sulphate, and 2-hydroxybenzoic acid in trace amounts. 4. Only the glucuronide and sulphate conjugates were detected as metabolites of 4-nitrophenol, 4-chlorophenol, and pentachlorophenol.
Fate of the herbicides glyphosate, glufosinate-ammonium, phenmedipham, ethofumesate and metamitron in two Finnish arable soils.
2006
The fate of five herbicides (glyphosate, glufosinate-ammonium, phenmedipham, ethofumesate and metamitron) was studied in two Finnish sugar beet fields for 26 months. Soil types were sandy loam and clay. Two different herbicide-tolerant sugar beet cultivars and three different herbicide application schedules were used. Meteorological data were collected throughout the study and soil properties were thoroughly analysed. An extensive data set of herbicide residue concentrations in soil was collected. Five different soil depths were sampled. The study was carried out using common Finnish agricultural practices and represents typical sugar beet cultivation conditions in Finland. The overall obse…
Sensitive screening of synthetic cannabinoids using liquid chromatography quadrupole time-of-flight mass spectrometry after solid phase extraction.
2021
Analysis of synthetic cannabinoids still poses a challenge for many institutions due to the number of available substances and the constantly changing drug market. Both new and well-known substances keep appearing and disappearing on the market, making it hard to adapt analytical methods in a timely manner. In this study, we developed a qualitative screening approach for synthetic cannabinoids and their metabolites by means of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Samples were measured in data-dependent auto-MS/MS mode and identified by fragment spectra, retention time and accurate mass. Two established solid phase extractions were compared using fo…
Extraction of Phenolic Compounds from Fresh Apple Pomace by Different Non-Conventional Techniques
2021
Red Delicious apple pomace was produced at laboratory scale with a domestic blender and different non-conventional extraction techniques were performed to isolate phenolic compounds, such as ultrasound-assisted extraction (UAE), ultraturrax extraction (UTE), accelerated solvent extraction (ASE) and pulsed electric field (PEF) extraction pre-treatment. Total phenolic content (TPC) was determined by Folin–Ciocalteu assay. Phloridzin, the main phenolic compound in apples, was determined by chromatographic analysis Q-TOF-LC/MS. The results obtained with these techniques were compared in order to identify the most efficient method to recover polyphenols. The highest value of TPC (1062.92 ± 59.80…
Metabolism of 3-nitrophenol by the frog Rana temporaria.
1986
1. Frogs injected with 3-nitrophenol excreted 85–93% of the administered dose within 17h; 70–90% dose was metabolized.2. Metabolites identified comprise 3-nitrophenyl glucuronide (57% dose), 3-nitro-phenyl sulphate (24% dose), and 3-acetamidophenyl sulphate (2% dose). Traces of the following metabolites were found: 3-acetamidophenyl glucuronide, 3-acetamidophenol, 4-nitrocatechol, nitroquinol, 4-nitrocatechol sulphate and nitroquinol sulphate.
Automated determination of clozapine and major metabolites in serum and urine.
1997
Clozapine is an atypical neuroleptic that is increasingly used for the treatment of schizophrenia. An automated method was developed for the routine quantification of clozapine and its major metabolites, N-desmethylclozapine and clozapine N-oxide, in human serum and urine by column switching and online high-performance liquid chromatography with ultraviolet detection. The method included adsorption of clozapine and its metabolites on a cyanopropyl-coated clean-up column (10 microns; 10 mm x 4.0 mm ID), washing interfering serum constituents to waste by deionized water, and, after column switching, separation on C18 ODS Hypersil reversed-phase material (5 microns; 250 mm x 4.6 mm ID). The co…
Gas chromatography/mass spectrometry of catechol estrogens
1992
Abstract Catecholestrogens (CCEs), namely 2- or 4-hydroxyestradiol and hydroxyestrone, are highly polar, reactive, and extremely labile estrogen metabolites in many experimental conditions. For these reasons, indirect assay methods mainly have been used. Some experimental evidence suggests that CCEs are synthesized and biologically active mostly in target cells. At this level, unfortunately, the indirect assays cannot be used. We present a method of gas Chromatographic/mass spectral (GC/MS) analysis for the identification of individual CCEs; the major fragmentation ions of authentic estrogen standards as trimethylsilylether derivatives, and the MS patterns of the major CCEs, namely, 2-hydro…
Analytical utility of quadrupole time-of-flight mass spectrometry for the determination of pesticide residues in comparison with an optimized column …
2009
Abstract A multiresidue method for the analysis of 30 pesticides with different physicochemical properties in fruits and vegetables was developed. The method involves a rapid and small-scale extraction procedure based on matrix solid-phase dispersion using octadecylsilyl (C18) as the dispersant and dichloromethane as the eluent. The target pesticides were determined using column high-performance liquid chromatography/triple quadrupole-tandem mass spectrometry (LC/QqQ-MS/MS). The method was validated for sensitivity, linearity, reproducibility, and accuracy. A recovery study was conducted at 3 different levels, and the average ranged from 74 to 99 for all of the studied compounds, with relat…
Quinol sulphate, a new conjugate of phenol in goldfish.
1983
1. Metabolism of phenol in goldfish yielded the known phenyl conjugates in fish--phenyl sulphate and phenyl glucuronide. Additionally, quinol sulphate, a new conjugate of phenol in fish, was detected.
Metabolism of phenol in the terrestrial snail Cepaea nemoralis L
1992
1. The metabolism of phenol in the terrestrial snail Cepaea nemoralis was studied after injection into the haemocoel of the dorsolateral foot region. 2. Excreted metabolites, and metabolites extracted from the body, were analysed by h.p.l.c. In addition to phenyl beta-D-glucoside, arbutine (quinol beta-D-glucoside), a new conjugate of phenol, was detected.