Search results for " sample"
showing 10 items of 456 documents
Determination of Glyphosate and AMPA in Food Samples Using Membrane Extraction Technique for Analytes Preconcentration
2021
The method for determining glyphosate (NPG) and its metabolite AMPA (aminomethyl phosphonic acid) in solid food samples using UAE-SLM-HPLC–PDA technique was developed. Firstly, ultrasonic-assisted solvent extraction (UAE) and protein precipitation step were used for the analyte isolation. Then, the supernatant was evaporated to dryness and redissolved in distilled water (100 mL). The obtained solution was alkalized to pH 11 (with 1 M NaOH) and used directly as donor phase in SLM (supported liquid membrane) extraction. The SLM extraction was performed using 2 M NaCl (5 mL) as an acceptor phase. The flow rate of both phases (donor and acceptor) was set at 0.2 mL/min. The membrane extraction t…
Determination of Glyphosate and AMPA in Food Samples Using Membrane Extraction Technique for Analytes Preconcentration
2022
The method for determining glyphosate (NPG) and its metabolite AMPA (aminomethyl phosphonic acid) in solid food samples using UAE-SLM-HPLC–PDA technique was developed. Firstly, ultrasonic-assisted solvent extraction (UAE) and protein precipitation step were used for the analyte isolation. Then, the supernatant was evaporated to dryness and redissolved in distilled water (100 mL). The obtained solution was alkalized to pH 11 (with 1 M NaOH) and used directly as donor phase in SLM (supported liquid membrane) extraction. The SLM extraction was performed using 2 M NaCl (5 mL) as an acceptor phase. The flow rate of both phases (donor and acceptor) was set at 0.2 mL/min. The membrane extraction t…
Multivariate optimization of the hollow fibre liquid phasemicroextraction of muscimol in human urine samples
2016
A liquid phase microextraction based on hollow fibre followed by liquid chromatographic determinationwas developed for the extraction and quantitation of the hallucinogenic muscimol from urine samples.Method applicability on polar hallucinogens was also tested on two alkaloids, a psychedelic hallucinogen,tryptamine and a polar amino acid, tryptophan which exists in its charged state in the entire pH range. Amultivariate design of experiments was used in which a half fractional factorial approach was applied toscreen six factors (donor phase pH, acceptor phase HCl concentration, carrier composition, stirring rate,extraction time and salt content) for their extent of vitality in carrier media…
"Voi ei, nää on tosi hyviä verrattuna muhun!" : uudenlaisen arviointimenetelmän toimivuus ranskan suullisen kielitaidon itsearvioinnissa
2013
Sample allocation for efficient model-based small area estimation
2017
We present research results on sample allocations for efficient model-based small area estimation in cases where the areas of interest coincide with the strata. Although model-assisted and model-based estimation methods are common in the production of small area statistics, utilization of the underlying model and estimation method are rarely included in the sample area allocation scheme. Therefore, we have developed a new model-based allocation named g1-allocation. For comparison, one recently developed model-assisted allocation is presented. These two allocations are based on an adjusted measure of homogeneity which is computed using an auxiliary variable and is an approximation of the int…
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…
A reappraisal of the purported gastric pellet with Pterosaurian bones from the Upper Triassic of Italy
2015
A small accumulation of bones from the Norian (Upper Triassic) of the Seazza Brook Valley (Carnic Prealps, Northern Italy) was originally (1989) identified as a gastric pellet made of pterosaur skeletal elements. The specimen has been reported in literature as one of the very few cases of gastric ejecta containing pterosaur bones since then. However, the detailed analysis of the bones preserved in the pellet, their study by X-ray microCT, and the comparison with those of basal pterosaurs do not support a referral to the Pterosauria. Comparison with the osteology of a large sample of Middle-Late Triassic reptiles shows some affinity with the protorosaurians, mainly with Langobardisaurus pand…
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…
Disability, Health-Related Quality of Life and Mortality in Lumbar Spine Fusion Patients : A 5-Year Follow-Up and Comparison With a Population Sample
2022
Study Design: Prospective follow-up study. Objectives: We aimed to assess the effect of lumbar spine fusion (LSF) on disability, health-related quality of life and mortality in a 5-year follow-up, and to compare these results with the general population. Methods: 523 consecutive LSF operations were included in a prospective follow-up. Disability was assessed by the Oswestry Disability Index (ODI), and HRQoL by the 36-item Short Form (SF-36) questionnaire using the physical and mental summary scores (PCS and MCS). The patients were compared with an age-, sex-, and residential area matched general population cohort. Results: The preoperative ODI in the patients was 46 (SD 16), and the change …
Evaluation of Superparamagnetic Silica Nanoparticles for Extraction of Triazines in Magnetic in-Tube Solid Phase Microextraction Coupled to Capillary…
2014
The use of magnetic nanomaterials for analytical applications has increased in the recent years. In particular, magnetic nanomaterials have shown great potential as adsorbent phase in several extraction procedures due to the significant advantages over the conventional methods. In the present work, the influence of magnetic forces over the extraction efficiency of triazines using superparamagnetic silica nanoparticles (NPs) in magnetic in tube solid phase microextraction (Magnetic-IT-SPME) coupled to CapLC has been evaluated. Atrazine, terbutylazine and simazine has been selected as target analytes. The superparamagnetic silica nanomaterial (SiO2-Fe3O4) deposited onto the surface of a capil…