Search results for: Lennart Mathiasson

Items from 1 to 20 out of 38 results

article

Selection of adsorbents for treatment of leachate: batch studies of simultaneous adsorption of heavy metals

Ülis Sõukand, Pille Kängsepp, Rutt Kakum, Toomas Tenno, more

Journal of Material Cycles and Waste Management > 2010 > 12 > 1 > 57-65

The simultaneous adsorption of copper (Cu), cadmium (Cd), nickel (Ni), and lead (Pb) ions from spiked deionized water and spiked leachate onto natural materials (peat A and B), by-product or waste materials (carbon-containing ash, paper pellets, pine bark, and semi-coke), and synthetic materials (based on urea-formaldehyde resins, called blue and red adsorbents) or mixtures thereof was investigated...

article

Occurrence and removal of pharmaceuticals in a municipal sewage treatment system in the south of Sweden

Saioa Zorita, Lennart Mårtensson, Lennart Mathiasson

Science of the Total Environment > 2009 > 407 > 8 > 2760-2770

The occurrence and removal rate of seven pharmaceuticals (ibuprofen, naproxen, diclofenac, fluoxetine, ofloxacin, norfloxacin, ciprofloxacin), two metabolites (norfluoxetine, clofibric acid), one degradation product (4-isobutylacetophenone) and 3 estrogens (17α-ethinylestradiol, 17β-estradiol, estrone) were studied in the inlet and outlet of a tertiary sewage treatment plant (STP) in Sweden as well...

article

Selective determination of acidic pharmaceuticals in wastewater using molecularly imprinted solid-phase extraction

Saioa Zorita, Brian Boyd, Stig Jönsson, Ecevit Yilmaz, more

Analytica Chimica Acta > 2008 > 626 > 2 > 147-154

The determination of acidic pharmaceuticals, such as non-steroidal anti-inflammatory drugs NSAIDs and clofibric acid (metabolite of clofibrate), at low ngL ⁻¹ levels in wastewater requires highly selective and sensitive analytical procedures. The removal of matrix components during sample preparation results in significant benefits towards reducing the matrix effects during LC–MS analysis...

article

Assessment of organochlorine pesticide pollution in Upper Awash Ethiopian state farm soils using selective pressurised liquid extraction

Rikard Westbom, Ahmed Hussen, Negussie Megersa, Negussie Retta, more

Chemosphere > 2008 > 72 > 8 > 1181-1187

Upper Awash Agro Industry Enterprises (UAAIE) is one of the major state farms in Ethiopia with known large-scale pesticide use. Although organochlorine pesticides (OCPs) have been applied for about three decades, no studies have been carried out on levels of residue in the region. In this work a fast selective pressurised liquid extraction (SPLE) methodology has successfully been applied for screening...

article

Steroid hormone determination in water using an environmentally friendly membrane based extraction technique

Saioa Zorita, Pär Hallgren, Lennart Mathiasson

Journal of Chromatography A > 2008 > 1192 > 1 > 1-8

In this study, a method was developed for determination of steroid hormones (17β-estradiol, estrone, 17α-ethynylestradiol) in tap and sewage water samples from Sweden. Sample preparation and analysis were performed by a hollow-fibre microporous membrane liquid–liquid extraction (HF-MMLLE) set-up combined with gas chromatography–mass spectrometry (GC–MS). In this approach, only the organic liquid in...

article

A novel hollow-fibre microporous membrane liquid–liquid extraction for determination of free 4-isobutylacetophenone concentration at ultra trace level in environmental aqueous samples

Saioa Zorita, Thaer Barri, Lennart Mathiasson

Journal of Chromatography A > 2007 > 1157 > 1-2 > 30-37

In this study, a method was developed for determination of the free concentration of 4-isobutylacetophenone, a toxic degradation product of ibuprofen, in river and sewage water samples from Sweden. Sample preparation and analysis were performed by a hollow-fibre microporous membrane liquid–liquid extraction (HF-MMLLE) set-up and gas chromatography–mass spectrometry (GC–MS), respectively. In this novel...

article

Extracting syringe for extraction of phthalate esters in aqueous environmental samples

Staffan Bergström, Thaer Barri, Jan Norberg, Jan Åke Jönsson, more

Analytica Chimica Acta > 2007 > 594 > 2 > 240-247

The use of the extracting syringe (ESy), a fully automated membrane-based extraction technique, for analysis of phthalate esters in complex aqueous samples has been investigated. The ESy, working as an autosampler that combines the extraction process and injection into the gas chromatograph (GC) in one single step, is placed on top of the GC equipped with a flame ionisation detector. The aqueous samples...

article

Selective pressurized liquid extraction for multi-residue analysis of organochlorine pesticides in soil

Ahmed Hussen, Rikard Westbom, Negussie Megersa, Lennart Mathiasson, more

Journal of Chromatography A > 2007 > 1152 > 1-2 > 247-253

A selective pressurized liquid extraction (SPLE) procedure capable of performing simultaneous extraction and clean-up has been demonstrated for multi-residue analysis of organochlorine pesticides (OCPs) in soil. The final method was performed at 100°C for 3×10min using acetone/n-heptane (1:1, v/v). Florisil was placed inside the extraction cell downstream the sample to remove interfering compounds...

article

Evaluation of PLE exhaustiveness for the extraction of PCBs from sediments and the influence of sediment characteristics

Sarah Josefsson, Rikard Westbom, Lennart Mathiasson, Erland Björklund

Analytica Chimica Acta > 2006 > 560 > 1-2 > 94-102

Pressurized liquid extractions were performed on eight sediments in order to investigate if a modified US EPA method (100°C, 100bar, n-heptane/acetone (1:1), 2×5min) provided exhaustive extractions of polychlorinated biphenyls (PCBs) from sediment, and to study if the extractability of PCBs from the different sediments was affected by characteristics of the sediment. The recovery from the eight native...

article

Development of a pressurized liquid extraction and clean-up procedure for the determination of α-endosulfan, β-endosulfan and endosulfan sulfate in aged contaminated Ethiopian soils

Ahmed Hussen, Rikard Westbom, Negussie Megersa, Lennart Mathiasson, more

Journal of Chromatography A > 2006 > 1103 > 2 > 202-210

Pressurized liquid extraction (PLE) was investigated for the extraction of two endosulfan isomers and their metabolite from two real contaminated soil samples. PLE for 3×10min at 100°C was proven to be more exhaustive than Soxhlet extraction (SOX) in one soil sample. On the other soil sample investigated the method was found to be equally exhaustive as SOX. The use of hazardous organic solvents such...

article

Optimisation of pressurised liquid extraction for the determination of p,p′-DDT and p,p′-DDE in aged contaminated Ethiopian soils

Ahmed Hussen, Rikard Westbom, Negussie Megersa, Negussie Retta, more

Analytical and Bioanalytical Chemistry > 2006 > 386 > 5 > 1525-1533

The effectiveness of extracting p,p′-DDT and p,p′-DDE from aged contaminated soil samples by means of pressurized liquid extraction (PLE) was evaluated. Two soil samples, which were contaminated more than 10 years ago, were used in the investigation. The static extraction time was optimised and then validated against the total sum of target analytes obtained from multiple sequential extractions. The...

article

Application of standard addition methodology for the determination of banned azo dyes in different leather types

Lars-Henric Ahlström, Johan Raab, Lennart Mathiasson

Analytica Chimica Acta > 2005 > 552 > 1-2 > 76-80

An analytical procedure based on microwave-assisted extraction (MAE) and standard addition was applied for the determination of banned azo dyes in bovine, sheep, and goat leather. Standard addition at four different concentration levels was performed using azo dyes, dissolved either in methanol or water. All dyes were determined indirectly by measuring their corresponding harmful aromatic amines,...

article

Optimization of an analytical procedure for the determination of banned azo dyes in leather

Lars-Henric Ahlström, Erland Björklund, Lennart Mathiasson

Analytical and Bioanalytical Chemistry > 2005 > 382 > 5 > 1320-1327

The possibility of improving an existing method, based on supercritical-fluid extraction (SFE) and microwave-assisted extraction (MAE), for the determination of banned azo dyes in leather has been studied. Thus, optimization of experimental conditions in different steps (degreasing, reduction, and extraction) of the analytical procedure was performed. The influence of different variables (reaction...

article

Development of a solid-phase extraction method for the determination of polychlorinated biphenyls in water

Rikard Westbom, Lars Thörneby, Saioa Zorita, Lennart Mathiasson, more

Journal of Chromatography A > 2004 > 1033 > 1 > 1-8

Polychlorinated biphenyls (PCBs) in water were extracted with a rebuilt extraction unit using 47mm C ₁ ₈ solid-phase extraction (SPE) disks. Three types of disks (SPEC, ENVI and Empore) were investigated for the extraction of seven PCBs from 1l reagent water spiked at two concentration levels (20 and 1000ng/l). The Empore disks produced the best analyte recoveries (91-107% with R.S.D....

article

On-line automated sample preparation for liquid chromatography using parallel supported liquid membrane extraction and microporous membrane liquid-liquid extraction

Margareta Sandahl, Lennart Mathiasson, Jan Åke Jönsson

Journal of Chromatography A > 2002 > 975 > 1 > 211-217

An automated system was developed for analysis of non-polar and polar ionisable compounds at trace levels in natural water. Sample work-up was performed in a flow system using two parallel membrane extraction units. This system was connected on-line to a reversed-phase HPLC system for final determination. One of the membrane units was used for supported liquid membrane (SLM) extraction, which is suitable...

article

Harmful azo colorants in leather - Determination based on their cleavage and extraction of corresponding carcinogenic aromatic amines using modern extraction techniques

Cecilia Sparr Eskilsson, Richard Davidsson, Lennart Mathiasson

Journal of Chromatography A > 2002 > 955 > 2 > 215-227

This study concerns the possibilities of using microwave-assisted extraction (MAE) or supercritical fluid extraction (SFE) for detection of harmful azo colorants in leather. After degreasing of the leather sample with SFE there follows a reductive cleavage of the azo colorants to their corresponding aromatic amines in the MAE or SFE equipment. The aromatic amines are subsequently extracted using either...

article

Supercritical fluid extraction and chromatography for fat-soluble vitamin analysis

Charlotta Turner, Jerry W. King, Lennart Mathiasson

Journal of Chromatography A > 2001 > 936 > 1-2 > 215-237

Extraction and chromatographic separation of fat-soluble vitamins is a challenging task, due to the sensitivity of these compounds towards light, oxygen, heat and pH. In light of this, supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) are attractive techniques as they function at considerably milder conditions than conventional solvent-based analytical techniques. Moreover,...

article

Lipase-catalyzed reactions in organic and supercritical solvents: application to fat-soluble vitamin determination in milk powder and infant formula

Charlotta Turner, Mattias Persson, Lennart Mathiasson, Patrick Adlercreutz, more

Enzyme and Microbial Technology > 2001 > 29 > 2-3 > 111-121

The aim of this study was to thoroughly investigate the possibility of using enzyme catalyzed hydrolysis and alcoholysis of ester bonds in vitamin A and E esters to facilitate their determination in different food formulas. Two vitamin esters, retinyl palmitate and α-tocopheryl acetate were used as model compounds and two food formulas, milk powder and infant formula, were used as model matrices....

article

On-Line Supercritical Fluid Extraction/Enzymatic Hydrolysis of Vitamin A Esters: A New Simplified Approach for the Determination of Vitamins A and E in Food

Charlotta Turner, Jerry W. King, Lennart Mathiasson

Journal of Agricultural and Food Chemistry > 2001 > 49 > 2 > 553 - 558

article

Membrane-based techniques for sample enrichment

Jan Åke Jönsson, Lennart Mathiasson

Journal of Chromatography A > 2000 > 902 > 1 > 205-225

Sample preparation techniques based on non-porous membrane extraction generally offer a high degree of selectivity and enrichment power, together with convenient possibilities for direct and automated connections to chromatographic and other analytical instruments. In this review principles and applications for techniques as supported liquid membrane extraction, microporous membrane liquid-liquid...

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Search results for: Lennart Mathiasson

Selection of adsorbents for treatment of leachate: batch studies of simultaneous adsorption of heavy metals

Occurrence and removal of pharmaceuticals in a municipal sewage treatment system in the south of Sweden

Selective determination of acidic pharmaceuticals in wastewater using molecularly imprinted solid-phase extraction

Assessment of organochlorine pesticide pollution in Upper Awash Ethiopian state farm soils using selective pressurised liquid extraction

Steroid hormone determination in water using an environmentally friendly membrane based extraction technique

A novel hollow-fibre microporous membrane liquid–liquid extraction for determination of free 4-isobutylacetophenone concentration at ultra trace level in environmental aqueous samples

Extracting syringe for extraction of phthalate esters in aqueous environmental samples

Selective pressurized liquid extraction for multi-residue analysis of organochlorine pesticides in soil

Evaluation of PLE exhaustiveness for the extraction of PCBs from sediments and the influence of sediment characteristics

Development of a pressurized liquid extraction and clean-up procedure for the determination of α-endosulfan, β-endosulfan and endosulfan sulfate in aged contaminated Ethiopian soils

Optimisation of pressurised liquid extraction for the determination of p,p′-DDT and p,p′-DDE in aged contaminated Ethiopian soils

Application of standard addition methodology for the determination of banned azo dyes in different leather types

Optimization of an analytical procedure for the determination of banned azo dyes in leather

Development of a solid-phase extraction method for the determination of polychlorinated biphenyls in water

On-line automated sample preparation for liquid chromatography using parallel supported liquid membrane extraction and microporous membrane liquid-liquid extraction

Harmful azo colorants in leather - Determination based on their cleavage and extraction of corresponding carcinogenic aromatic amines using modern extraction techniques

Supercritical fluid extraction and chromatography for fat-soluble vitamin analysis

Lipase-catalyzed reactions in organic and supercritical solvents: application to fat-soluble vitamin determination in milk powder and infant formula

On-Line Supercritical Fluid Extraction/Enzymatic Hydrolysis of Vitamin A Esters: A New Simplified Approach for the Determination of Vitamins A and E in Food

Membrane-based techniques for sample enrichment

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