BACKGROUND An important question is whether human serum levels of persistent organic pollutants has continued to decrease during the last decades. The aim of this study was to assess intra-individual variations over time of serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) and hexachlorobenzene (HCB), considering the impact of a n...

BACKGROUND Effective enzymatic hydrolysis of lignocellulosic biomass benefits from lignin removal, relocation, and/or modification during hydrothermal pretreatment. Phase transition, depolymerization/repolymerization, and solubility effects may all influence these lignin changes. To better understand how lignin is altered, Populus trichocarpa x P. deltoides wood samples and cellulolytic enzyme ...

The products of microbial transformation of 2,4-dinitrotoluene by Mucrosporium sp. were identified by thin-layer chromatography and by gas chromatography/mass spectrometry as 2-amino-4-nitrotoluene, 4-amino-2-nitrotoluene, 2,2'-dinitro-4,4'-azoxytoluene, 4,4'-dinitro-2,2'-azoxytoluene, and 4-acetamido-2-nitrotoluene. A third azoxy compound, believed to be a "mixed" type (i.e., 2,4'-azoxy or 4,2...

dispersive liquid liquid microextraction (dllme) combined with gas chromatography–mass spectrometry (gc–ms) was used for the extraction and determination of 13 polycyclic aromatic hydrocarbons (pahs) in mineral water samples. in this procedure, the suitable combination of extraction solvent (500 µl chloroform) and disperser solvent (1000 µl acetone) were quickly injected into the water sample (...

Econea®, or 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile, is a new type of environmentally friendly anti-fouling compound used in the immersed coatings of commercial sea going vessels. This paper reports the development of a new analytical method to directly detect the active biocide Econea® in an artificial sea water matrix using liquid chromatography mass spectrome...

Two archaeological specimens of peyote buttons, i.e. dried tops of the cactus Lophophora williamsii (Lem.) Coulter, from the collection of the Witte Museum in San Antonio, was subjected to radiocarbon dating and alkaloid analysis. The samples were presumably found in Shumla Cave No. 5 on the Rio Grande, Texas. Radiocarbon dating shows that the calibrated 14C age of the weighted mean of the two ...

Endogenous indoleacetic acid (IAA) levels of Euphorbia esula L. primary root and root buds were examined at three phenologic stages. High performance liquid chromatography coupled with fluorescence detection and gas chromatography-mass spectrometry, using (13)C(6)[benzene ring]-indole-3-acetic acid as internal standard, were used to measure root bud free and bound IAA levels in vegetative, full...

Wood compounds, especially sterols, are connected with the level of contamination with microscopic fungi. Within this study, tests were conducted on wood dust samples collected at various work stations in a pine and birch timber conversion plant. Their contamination with mycobiota was measured as the concentration of ergosterol (ERG) by ultra performance liquid chromatography (UPLC). Another ai...