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- Dock, Eva, et al.
(författare)
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Multivariate data analysis of dynamic amperometric biosensor responses from binary analyte mixtures - application of sensitivity correction algorithms
- 2005
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Ingår i: Talanta. - : Elsevier BV. - 1873-3573 .- 0039-9140. ; 65:2, s. 298-305
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, it is demonstrated that a single-receptor biosensor can be used to quantitatively determine each analyte in binary Mixtures LIS in multivariate data analysis tools based on the dynamic responses received from flow injection peaks. Mixtures with different concentrations of two phenolic compounds, catechol and 4-chlorophenol, were measured with a graphite electrode modified with tyrosinase enzyme at an applied potential of -50 mV versus Ag/AgCl. A correction algorithm based on measurements of references in-between samples was applied to compensate for biosensor ageing as well as differences caused by deviations between biosensor preparations. After correction, the relative prediction errors with partial least squares regression (PLS-R) for catechol and 4-chlorophenol were 7.4 and 5.5%, respectively, using an analysis sequence measured on one biosensor. Additional validation mixtures of the two phenols were measured with a new biosensor, prepared with the same procedure but with a different batch of tyrosinase enzyme. Using the mixture responses for the first sensor as a calibration set in PLS-R. the relative prediction errors of the validation mixtures, after applying correction procedures. were 7.0% for catechol and 16.0% for 4-chlorophenol. These preliminary results indicate that by applying correction algorithms it could be possible to use less stable biosensors in continuous on-line measurements together with multivariate data analysis without time-consuming calibration procedures. (C) 2004 Elsevier B.V. All rights reserved.
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- Tonning, E, et al.
(författare)
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Chemometric exploration of an amperometric biosensor array for fast determination of wastewater quality
- 2005
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 21:4, s. 608-617
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Tidskriftsartikel (refereegranskat)abstract
- Four wastewater samples of different treatment qualities; untreated, alarm, alert and normal, from a Swedish chen-ti-thermo-mechanical pulp mill and pure water were investigated using an amperometric bioelectronic tongue in a batch cell. The aim was to explore enzymatically modified screen-printed amperometric sensors for the discrimination of wastewater quality and to counteract the inherent drift. Seven out of eight platinum electrodes on the array were modified with four different enzymes; tyrosinase, horseradish peroxidase, acetyl cholinesterase and butyryl cholinesterase. At a constant potential the current intensity on each sensor was measured for 200s, 100s before injection and 100s after injection of the sample. The dynamic biosensor response curves from the eight sensors were used for principal component analysis (PCA). A simple baseline and sensitivity correction equivalent to multiplicative drift correction (MDC), using steady state intensities of reference sample (catechol) recordings, was employed. A clear pattern emerged in perfect agreement with prior knowledge of the samples explaining 97% of the variation in the data by two principal components (PCs). The first PC described the treatment quality of the samples and the second PC described the difference between treated and untreated samples. Horseradish peroxidase and pure platinum sensors were found to be the determinant sensors, while the rest did not contribute much to the discrimination. The wastewater samples were characterized by the chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), inhibition of nitrification, inhibition of respiration and toxicity towards Vibrio fischeri using Microtox (R), the freshwater alga Pseudokirchneriella subcapita and the freshwater crustacean Daphnia magna. (c) 2005 Elsevier B.V. All rights reserved.
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