Ulrika Nordlöf - Academia.edu (original) (raw)
Papers by Ulrika Nordlöf
Analytical Chemistry, 2003
A new supported liquid membrane extractor for bioanalytical sample preparation is presented. The ... more A new supported liquid membrane extractor for bioanalytical sample preparation is presented. The extractor consists of a polypropylene hollow fiber mounted inside a PTFE tube by means of a cross-connector and a teeconnector. All parts are commercially available, inexpensive, and easily assembled. An organic solvent in the pores of the fiber forms a liquid membrane that separates the sample, which is pumped along the outside of the fiber, from the acceptor phase, which is pumped inside. The length of the hollow fiber may easily be varied to meet different demands on extractive surface and extract volumes. To test the system, the strongly acidic plasticizer/ flame retardant metabolite diphenyl phosphate ester (DPhP), with a pK a value of 0.26, was extracted from urine. DPhP was protonated using 4 M hydrochloric acid and extracted into an acceptor phase at pH 9. Thirty extractions were made with the same liquid membrane without any decrease in extraction efficiency and with a relative standard deviation <7%. An analyte concentration enrichment of 5-10 times was achieved in the extraction step, giving a limit of detection (S/N ) 3) of 0.014 µg/ mL with LC/ESI-MS and 0.18 µg/mL with CE-UV. The effects on extraction efficiency using different sample pH, organic solvents, sample flow rates, and lengths of the fiber were evaluated.
Science of The Total Environment, 2010
Forty-four unhatched eggs from white-tailed sea eagle (Haliaeetus albicilla), collected in four r... more Forty-four unhatched eggs from white-tailed sea eagle (Haliaeetus albicilla), collected in four regions in Sweden in 1992-2005, were analysed for contents of polybrominated diphenyl ethers (PBDEs), polybrominated biphenyl (PBB), hexabromocyclododecane (HBCD) and naturally occurring methoxylated polybrominated diphenyl ethers (MeO-PBDEs). Two freshwater areas-Lapland in the arctic zone (LAP) and inland lakes in central and southern Sweden (INL), and two brackish marine areas in the Baltic Sea-the south Bothnian Sea (SB) and the Baltic Proper (BP)-were chosen for comparison of the concentrations and congener distributions in white-tailed sea eagles with different diet and migratory patterns. The geometric mean (GM) concentrations (ng/g lipid weight (l.w.)) of ∑ 5 PBDE (BDE-47, -99, -100, -153, and -154) were 720 (LAP), 1500 (INL), 4 100 (SB) and 4 300 (BP), whereas BDE-209 was not detectable in any of the samples. The GM concentrations for HBCD content in LAP, INL, SB and BP were 60, 90, 150 and 140 ng/g l.w., respectively, whereas the corresponding values for BB-153 were 20, 30, 100 and 120 ng/g l.w. In general, the eggs from all four regions demonstrated similar patterns of PBDE congeners, with concentrations in descending order of BDE-47, -100, -99, -153 and -154. The ∑ 3 -MeO-BDEs (6-MeO-BDE47, 2′-MeO-BDE68
Analytical Chemistry, 2003
A new supported liquid membrane extractor for bioanalytical sample preparation is presented. The ... more A new supported liquid membrane extractor for bioanalytical sample preparation is presented. The extractor consists of a polypropylene hollow fiber mounted inside a PTFE tube by means of a cross-connector and a teeconnector. All parts are commercially available, inexpensive, and easily assembled. An organic solvent in the pores of the fiber forms a liquid membrane that separates the sample, which is pumped along the outside of the fiber, from the acceptor phase, which is pumped inside. The length of the hollow fiber may easily be varied to meet different demands on extractive surface and extract volumes. To test the system, the strongly acidic plasticizer/ flame retardant metabolite diphenyl phosphate ester (DPhP), with a pK a value of 0.26, was extracted from urine. DPhP was protonated using 4 M hydrochloric acid and extracted into an acceptor phase at pH 9. Thirty extractions were made with the same liquid membrane without any decrease in extraction efficiency and with a relative standard deviation <7%. An analyte concentration enrichment of 5-10 times was achieved in the extraction step, giving a limit of detection (S/N ) 3) of 0.014 µg/ mL with LC/ESI-MS and 0.18 µg/mL with CE-UV. The effects on extraction efficiency using different sample pH, organic solvents, sample flow rates, and lengths of the fiber were evaluated.
Science of The Total Environment, 2010
Forty-four unhatched eggs from white-tailed sea eagle (Haliaeetus albicilla), collected in four r... more Forty-four unhatched eggs from white-tailed sea eagle (Haliaeetus albicilla), collected in four regions in Sweden in 1992-2005, were analysed for contents of polybrominated diphenyl ethers (PBDEs), polybrominated biphenyl (PBB), hexabromocyclododecane (HBCD) and naturally occurring methoxylated polybrominated diphenyl ethers (MeO-PBDEs). Two freshwater areas-Lapland in the arctic zone (LAP) and inland lakes in central and southern Sweden (INL), and two brackish marine areas in the Baltic Sea-the south Bothnian Sea (SB) and the Baltic Proper (BP)-were chosen for comparison of the concentrations and congener distributions in white-tailed sea eagles with different diet and migratory patterns. The geometric mean (GM) concentrations (ng/g lipid weight (l.w.)) of ∑ 5 PBDE (BDE-47, -99, -100, -153, and -154) were 720 (LAP), 1500 (INL), 4 100 (SB) and 4 300 (BP), whereas BDE-209 was not detectable in any of the samples. The GM concentrations for HBCD content in LAP, INL, SB and BP were 60, 90, 150 and 140 ng/g l.w., respectively, whereas the corresponding values for BB-153 were 20, 30, 100 and 120 ng/g l.w. In general, the eggs from all four regions demonstrated similar patterns of PBDE congeners, with concentrations in descending order of BDE-47, -100, -99, -153 and -154. The ∑ 3 -MeO-BDEs (6-MeO-BDE47, 2′-MeO-BDE68