| 1. |
- Kroger, S, et al.
(författare)
-
Imprinted polymer based sensor system for herbicides using differential-pulse voltammetry on screen printed electrodes
- 1999
-
Ingår i: Analytical Chemistry. - : ACS American Chemical Society. - 0003-2700 .- 1520-6882. ; 71:17, s. 3698-3702
-
Tidskriftsartikel (refereegranskat)abstract
- A sensor system for the herbicide 2,4-dichlorophenoxyacetic acid has been developed based on specific recognition of the analyte by a molecularly imprinted polymer and electrochemical detection using disposable screen-printed electrodes. The method involves a competitive binding step with a nonrelated electrochemically active probe. For batch binding assays, imprinted polymer particles are incubated in suspension with the analyte and the probe, followed by centrifugation and quantification of the unbound probe in die supernatant. Two different compounds, namely 2,4-dichlorophenol and homogentisic acid, were tested as potential electroactive probes. Both compounds could be conveniently detected by differential-pulse voltammetry on screen-printed, solvent-resistant three-electrode systems having carbon working electrodes. Whereas 2,4-dichlorophenol showed very high nonspecific binding to the polymer, homogentisic acid bound specifically to the imprinted sites and thus allowed calibration curves for the analyte in the micromolar range to be recorded. An integrated sensor was developed by coating the imprinted polymer particles directly onto the working electrode. Following incubation of the modified electrode in a solution containing the analyte and the probe, the bound fraction of the probe is quantified. This system provides a cheap, disposable sensor for rapid determination of environmentally relevant and other analytes.
|
|
| 2. |
- Nilsson, S, et al.
(författare)
-
Real-time Fluorescence Imaging of Capillary Electrophoresis
- 1995
-
Ingår i: Journal of Capillary Electrophoresis. - 1079-5383. ; 2:1, s. 46-52
-
Tidskriftsartikel (refereegranskat)abstract
- An arrangement for real-time fluorescence imaging of capillary electrophoretic separations is described. A decoated capillary was excited along a substantial part of its length by a dye laser pumped with an XeCl excimer laser tuned to match the fluorophors in the sample. Light emitted from the migrating, fluorescent molecules was detected by an image-intensified, thermoelectrically cooled charge-coupled device camera. The camera signals were processed by a computer and displayed as moving peaks on a screen in real-time, thus allowing the progress of the separation to be monitored continuously. Basic characteristics of the imaging arrangement such as sensitivity (signal-to-noise ratio) and resolution were checked with fluorescein samples. The imaging principle was also illustrated with a separation of a mixture of DNA fragments on a commercially available capillary designated for DNA separations. The benefits of real-time imaging for separation processes, in particular for capillary electrophoresis, are discussed.
|
|
| 3. |
|
|
| 4. |
- Andersson, L I, et al.
(författare)
-
Immunoassays using molecularly imprinted polymers
- 1995
-
Ingår i: Immunoanalysis of agrochemicals. - : American Chemical Society (ACS). - 0841231494 ; , s. 89-97
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Carlsson, Jonas, et al.
(författare)
-
Affinity precipitation and site-specific immobilization of proteins carrying polyhistidine tails
- 1996
-
Ingår i: Biotechnology and Bioengineering. - 0006-3592. ; 51:2, s. 8-221
-
Tidskriftsartikel (refereegranskat)abstract
- Proteins carrying genetically attached polyhistidine tails have been purified using affinity precipitation with metal chelates. DNA fragments encoding four or five histidine residues have been genetically fused to the oligomeric enzymes lactate dehydrogenase (Bacillus stearothermophilus), beta-glucoronidase (Escherichia coli), and galactose dehydrogenase (Pseudomonas fluorescens) as well as to the monomeric protein A (Staphylococcus aureus). The chimeric genes were subsequently expressed in E. coli. The engineered enzymes were successfully purified from crude protein solutions using ethylene glycolbis (beta-aminoethyl) tetraacetic acid (EGTA) charged with Zn(2+) as precipitant, whereas protein A, carrying only one attached histidine tail, did not precipitate. However, all of the engineered proteins could be purified on immobilized metal affinity chromatography (IMAC) columns loaded with Zn(2+). The potential of using the same histidine tails for site-specific immobilization of proteins was also investigated. The enzymes were all catalytically active when immobilized on IMAC gels. For instance, immobilized lactate dehydrogenase, carrying tails composed of four histidine residues, displaced 83% of the soluble enzyme activity.
|
|
| 9. |
|
|
| 10. |
|
|
