Search results for "CAPI"
showing 10 items of 2622 documents
On-line analysis of carbonyl compounds with derivatization in aqueous extracts of atmospheric particulate PM10 by in-tube solid-phase microextraction…
2011
Abstract A new device for carbonyl compounds based on coupling on-line and miniaturizing both, sample pretreatment and chromatographic separation, is reported. Two capillary columns, a GC capillary column (95% methyl–5% phenyl substituted backbone, 70 cm × 0.32 mm i.d., 3 μm film thickness) in the injection valve for in-tube solid-phase microextraction (IT-SPME) and a Zorbax SB C18 (150 mm × 0.5 mm i.d., 5 μm particle diameter) LC capillary column were employed. Different combinations of IT-SPME and derivatization using 2,4-dinitrophenylhydrazine (DNPH) were examined for mixtures containing 15 carbonyl compounds (aliphatic, aromatic and unsaturated aldehydes and ketones). A screening analys…
A direct Capillary Liquid Chromatography with electrochemical detection method for determination of phenols in water samples
2010
A fast and direct method based on the use of Capillary Liquid Chromatography (LC) with electrochemical (EC) detection has been described for phenols pollutants in water samples. Concretely, phenol, o-cresol, 2-chlorophenol and bisphenol A have been selected as target analytes. The combination of Capillary LC with EC detection avoided the necessity of preconcentration steps typically used in environmental analysis. The sample injected volume was 2 μL. The achieved detection limits were between 1 and 2 μg/L and the linear dynamic range was up to 50 μg/L for all studied phenols. The precision and uncertainty were satisfactory. The analysis time per sample was 10 min. The proposed procedure has…
Advantages of monolithic over particulate columns for multiresidue analysis of organic pollutants by in-tube solid-phase microextraction coupled to c…
2011
Abstract The performance of a monolithic C 18 column (150 mm × 0.2 mm i.d.) for multiresidue organic pollutants analysis by in-tube solid-phase microextraction (IT-SPME)-capillary liquid chromatography has been studied, and the results have been compared with those obtained using a particulate C 18 column (150 mm × 0.5 mm i.d., 5 μm). Chromatographic separation has been carried out under isocratic elution conditions, and for detection and identification of the analytes a UV-diode array detector has been employed. Several compounds of different chemical structure and hydrophobicity have been used as model compounds: simazine, atrazine and terbutylazine (triazines), chlorfenvinphos and chlorp…
Exploring hand-portable nano-liquid chromatography for in place water analysis: Determination of trimethylxanthines as a use case.
2020
Abstract Analytical performance and optimization of figures of merit of a portable nano liquid chromatograph (NanoLC) with UV detection at 255 nm have been established for in place analysis. Methylxanthines: caffeine, theophylline and theobromine were selected as target analytes. A fast lab method based on IT-SPME coupled on line with capillary liquid chromatograph (CapLC) with diode array detection (DAD) was employed for comparative studies. IT-SPME and solid phase extraction were coupled off-line to NanoLC for improving instrumental parameters, mainly detection capacity and selectivity. IT-SPME or SPE/portable NanoLC based methods were superior in terms of chromatographic resolution and o…
Method and apparatus using selected superparamagnetic labels for rapid quantification of immunochromatographic tests
2009
Mika PA Laitinen1, Jari Salmela2, Leona Gilbert1, Risto Kaivola1, Topi Tikkala2, Christian Oker-Blom1, Jukka Pekola3, Matti Vuento11Department of Biological and Environmental Science; 2Department of Physics, University of Jyväskylä, Jyväskylä, Finland; 3Low Temperature Laboratory, Helsinki University of Technology, Helsinki, FinlandAbstract: A rapid method and instrumentation for quantification of immunochromatographic tests (ICT) are described. The principle and performance of the method was demonstrated by measuring the levels of human chorionic gonadotropin (hCG) present in urine. The test format was a sandwich assay using two distinct monoclonal antib…
Immunochromatographic Assay for Quantitation of Milk Progesterone.
1996
We describe a rapid immunochromatographic method for the quantitation of progesterone in bovine milk. The method is based on a 'competitive' assay format using the monoclonal antibody to progesterone and a progesterone-protein conjugate labelled with colloidal gold particles. The monoclonal antibody to progesterone is immobilized as a narrow detection zone on a porous membrane. The sample is mixed with colloidal gold particles coated with progesterone-protein conjugate, and the mixture is allowed to migrate past the detection zone. Migration is facilitated by capillary forces. The amount of labelled progesterone-protein conjugate bound to the detection zone, as detected by photometric scann…
Capillary electrophoresis for the determination of pesticide residues
2003
Capillary electrophoresis (CE) is becoming an advantageous tool for determining pesticide residues in environmental matrices because of its simplicity and high separation efficiency. However, inadequate limits of detection (LODs) and a lack of selective detectors limit the technique. The present review gives an overview of current developments in off-column and on-column approaches to trace enrichment in analysing real samples, and summarises the determination of pesticides residues by conventional CE as well as by the emerging techniques, such as CE-mass spectrometry (MS). The usefulness of these approaches in environmental applications is documented.
Separation of plutonium and neptunium species by capillary electrophoresis-inductively coupled plasma-mass spectrometry and application to natural gr…
2003
Capillary electrophoresis (CE) was coupled to ICPMS in order to combine the good performance of this separation technique with the high sensitivity of the ICPMS for the analysis of plutonium and neptunium oxidation states. The combination of a fused-silica capillary with a MicroMist AR 30-I-FM02 nebulizer and a Cinnabar small-volume cyclonic spray chamber yielded the best separation results. With this setup, it was possible to separate a model element mixture containing neptunium (NpO2(+)), uranium (UO2(2+)), lanthanum (La3+), and thorium (Th4+) in 1 M acetic acid. The same conditions were also suitable for the separation of various oxidation states of plutonium and neptunium in different a…
Determination of thyreostatics in animal feed by micellar electrokinetic chromatography
1999
The determination of the thyreostatics 2-thiouracil, its derivatives (4-methyl-2-thiouracil, 4-propyl-2-thiouracil and 4-phenyl-2-thiouracil) and methimazole in manufactured dried animal feed by micellar electrokinetic chromatography (MEKC) is described. A 99 +/- 5% extraction yield at the 20 micrograms g-1 level (n = 8) was achieved by shaking the milled fodder with methanol-1 M NaOH (80 + 20). Aliquots of the supernatant were injected in a 75 microns x 33.5 cm uncoated silica capillary using pressure; separation was performed at 23 degrees C with 15 kV (positive polarity) in a background electrolyte (BGE) containing 40 mM sodium dihydrogenphosphate, 50 mM sodium dodecyl sulfate and 15 mM …
On-line removal of mass interferences in palladium determination by ICP-MS using modified capillaries coupled to micro-flow nebulizers
2001
This paper describes a novel approach developed for on-line removal of interferences within modified capillaries coupled to micro-flow nebulizers, for palladium determination by inductively coupled plasma mass spectrometry (ICP-MS). A strong cation exchanger [2-(4-chlorosulfophenyl)ethyltrichlorosilane)] was covalently bound to the silica capillary that was coupled to a microconcentric nebulizer (MCN) or to a direct injection nebulizer (DIN). The modified surface of the capillary was able to selectively retain copper and yttrium from aqueous samples at pH 7.5 during the sample introduction step, while Pd was not retained and 105Pd could be determined in the absence of interferent elements. …