Search results for "Extraction"
showing 10 items of 2072 documents
Occurrence of pharmaceuticals in municipal wastewater treatment plants and receiving surface waters in Central and Southern Finland
2016
The presence of five selected pharmaceuticals, four anti-inflammatory drugs, diclofenac, ibuprofen, ketoprofen, naproxen, and an antiepileptic drug carbamazepine, was determined at four municipal wastewater treatment plants (WWTPs) and in the receiving waterway near the city of Jyväskylä, in central Finland and also in the River Vantaa. First, an analytical method was developed including a pretreatment and purification followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The studied pharmaceuticals were detected from influents and effluents of four municipal WWTPs and from surface water of eight locations along the water …
ANALYTICAL PROCEDURES FOR THE DETERMINATION OF TRACE AMOUNTS OF XENOBIOTICS IN ENVIRONMENTAL WATER SAMPLES
2016
Wciąż wzrastające zanieczyszczenie środowiska związane z działalnością człowieka stanowi poważny problem ekologiczny współczesnego świata. Ksenobiotyki to substancje obce i potencjalnie szkodliwe dla organizmów żywych. Obecność niektórych z nich w środowisku wodnym może nieść za sobą poważne konsekwencje. Do najbardziej niebezpiecznych należą antybiotyki oraz pestycydy. Rozwój nauki i techniki umożliwił kontrolowanie tych substancji w środowisku naturalnym. Oznaczanie śladowych ilości ksenobiotyków w próbkach wód środowiskowych jest złożonym procesem, wymagającym zastosowania odpowiedniej metody ekstrakcyjnej i analitycznej. Złożoność matrycy oraz obecność substancji współobecnych stanowi d…
Extraction of lapachol from Tabebuia avellanedae wood with supercritical CO2: an alternative to Soxhlet extraction?
2003
The solubility of lapachol in supercritical CO2 was determined at 40°C and pressures between 90 and 210 bar. Supercritical fluid extraction of lapachol and some related compounds by CO2 from Tabebuia avellanedae wood is compared to Soxhlet extraction with different solvents. A standard macroscale (100-200 g wood) and a microscale (~10 mg wood) experimental setup are described and their results are compared. The latter involved direct spectrophotometric quantification in a high-pressure autoclave with an integrated optical path and a magnetic stirrer, fitted directly into a commercial spectrophotometer. The relative amount of lapachol extracted by supercritical CO2 at 40°C and 200 bar was ab…
Influences of rhythm- and timbre-related musical features on characteristics of music-induced movement
2013
Music makes us move. Several factors can affect the characteristics of such movements, including individual factors or musical features. For this study, we investigated the effect of rhythm- and timbre-related musical features as well as tempo on movement characteristics. Sixty participants were presented with 30 musical stimuli representing different styles of popular music, and instructed to move along with the music. Optical motion capture was used to record participants’ movements. Subsequently, eight movement features and four rhythm- and timbre-related musical features were computationally extracted from the data, while the tempo was assessed in a perceptual experiment. A subsequent c…
Shoreline Extraction and Change Detection using 1:5000 Scale Orthophoto Maps: A Case Study of Latvia-Riga
2015
Coastal management requires rapid, up-to-date, and
 correct information. Thus, the determination of coastal movements and its
 directions has primary importance for coastal managers. For monitoring the
 change of shorelines, remote sensing data, very high resolution aerial images
 and orthophoto maps are utilized for detections of change on shorelines. It is
 possible to monitor coastal changes by extracting the coastline from orthophoto
 maps. Along the Baltic Sea and Riga Gulf, Latvian coastline length is 496 km.
 It is rich of coastal resources and natural biodiversity.  Around 120 km of coastline are affected by
 significant coastal chang…
Dynamic of Components Leachate from Experimental Fertilizers in Leaching Test
2018
Organic matter contained in the waste of food industry or occurring in the households, in the absence of contamination with other kind of waste, may be used to create a “fertiliser”, which could be even reused in the organic production of arable crops. Particular attention is drawn to the fertilisers which may be applied in the case of amateur cultivation of pot plants and in the allotment gardens. The paper presents the results of research regarding the dynamics of the release of nutrients from tablets created with the help of encapsulation of the mixture manufactured from solvent extraction waste of coffee (SCG), modified by the ash obtained from low temperature burning of biomass. In thi…
Liquid Phase Micro-Extraction of Linear Alkylbenzene Sulfonate Anionic Surfactants in Aqueous Samples
2011
Hollow fiber liquid phase micro-extraction (LPME) of linear alkylbenzene sulfonates (LAS) from aqueous samples was studied. Ion pair extraction of C10, C11, C12 and C13 homologues was facilitated with trihexylamine as ion-pairing agent, using di-n-hexylether as solvent for the supported liquid membrane (SLM). Effects of extraction time, acceptor buffer concentration, stirring speed, sample volume, NaCl and humic acids were studied. At 10–50 µg L−1 linear R2-coefficients were 0.99 for C10 and C11 and 0.96 for C12. RSD was typically ~15%. Three observations were especially made. Firstly, LPME for these analytes was unusually slow with maximum enrichment observed after 15–24 h (depending on sa…
Analysis of Lipophilic Extractives from Fast Pyrolysis Bio-Oils
2022
Fast pyrolysis bio-oils (FPBOs) originating from forest residues contain extractive-derived substances, which may form a separate, sticky layer with char particles on the surface of these bio-oils. In this study, first, the removal of extractive-derived substances from the bio-oil top phase was studied by common solvents with different polarities. In this case, the results indicated that when aimed at the maximum yield of single-phase fuel oil and thus the maximum amount of extractives removed, the use of n-heptane or n-hexane seems to be of benefit for this purpose. For safety reasons, the use of n-heptane was recommended. Second, an analysis practice (extraction time and the way of mixing…
A multiresidue analytical method for trace level determination of antibiotics and antiretroviral drugs in wastewater and surface water using SPE-LC-M…
2016
An analytical method for simultaneous determination of seven commonly used antibiotics and three antiretrovirals in surface water and urban wastewater at the ng L−1 level has been developed. The method involves concentration and clean-up by solid phase extraction (SPE) followed by identification and quantification by liquid chromatography tandem mass spectrometry (LC-ESI-MS/MS). The use of matrix-matched calibration curves constructed by spiking surface water was evaluated for quantification and compared with the internal standard method using isotopically labelled compounds. The method gave absolute recoveries of 41–116% with most of the compounds having recoveries >50%. The LOQs ranged fr…
Liquid membranes as a sample preparation method in environmental analysis
2014
Because of the complexity of environmental matrices, there is a great need of application efficient sample preparation procedures for environmental analysis. One of such possibilities is using, during sample-pretreatment step, the membrane extraction (ME) methods. They include, for instance, a three-phase extraction system named supported liquid membranes that has been used in recent years many times for isolation and preconcentration of various analytes from complex sample matrices. The examples of application the commonly used types of SLMs, hollow fiber supported liquid membrane and flat sheet supported liquid membrane, are listed and described. Additionally, the area of membrane extract…