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Krantz-Rülcher, Christina
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Publikasjoner (10 av 28) Visa alla publikasjoner
Bjorklund, R., Louthander, D., Martensson, P., Andersson, S., Kvist, E., Ohrn, M. & Krantz-Rülcker, T. (2010). Online monitoring of inorganic cooking chemicals in white liquor by pulse voltammetry. TAPPI JOURNAL, 9(8), 49-53
Åpne denne publikasjonen i ny fane eller vindu >>Online monitoring of inorganic cooking chemicals in white liquor by pulse voltammetry
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2010 (engelsk)Inngår i: TAPPI JOURNAL, ISSN 0734-1415, Vol. 9, nr 8, s. 49-53Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

White liquor parameters in the recovery area of a kraft pulp mill were monitored for a 1-year period using rhodium as an electrode material in a sensor system based on pulse voltammetry. Shift personnel performed offline titration analysis of the liquor every 4 hours. The results for effective alkali, sulfidity, and total titratable alkali were used to train and validate the sensor for online monitoring. Partial least square regression models developed from 150 reference titration results for each parameter from the first month of the study predicted concentrations for the following 11 months. Validation of the models using titration results indicated that overall relative root mean squared errors for prediction of the parameters were 3.7% for effective alkali, 3.4% for sulfidity, and 5.1% for total titratable alkali. Process stops that exposed the sensor to temperature excursions or acid washings resulted in temporary periods of poor prediction.

sted, utgiver, år, opplag, sider
Tappi Press, 2010
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-64233 (URN)000285249400006 ()
Tilgjengelig fra: 2011-01-17 Laget: 2011-01-17 Sist oppdatert: 2011-01-17
Bjorklund, R., Magnusson, C., Martensson, P., Winquist, F. & Krantz-Rülcher , C. (2009). Continuous monitoring of yoghurt fermentation using a noble metal electrode array. International Journal of Food Science and Technology, 44(3), 635-640
Åpne denne publikasjonen i ny fane eller vindu >>Continuous monitoring of yoghurt fermentation using a noble metal electrode array
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2009 (engelsk)Inngår i: International Journal of Food Science and Technology, ISSN 0950-5423, Vol. 44, nr 3, s. 635-640Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

An electrochemical probe containing gold, platinum and rhodium working electrodes was used to monitor yoghurt production in a pilot facility. Three commercial starting cultures at 40, 42 and 44 C transformed milk having 1.5% fat content to mild yoghurt products. The electrochemical changes in the broth during fermentation were recorded as current responses from pulse voltammetry over the electrodes. Principal component analysis of the responses generated two-dimensional score plots describing the qualitative fermentation progressions. Two distinct fermentation pathways were observed leading to similar final products. The pH was recorded during the fermentations and the data was used as reference values for creating a partial least squares model for prediction of pH as an example of a quantitative application for the sensor. The relative mean squared error for validation of the model using four probes interchangeably was about 2%. The probe was constructed of materials approved for use in the food industry and did not require a standard glass reference electrode.

Emneord
Multivariate analysis; pH; Process monitoring; Voltammetry; Yoghurt
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-18833 (URN)10.1111/j.1365-2621.2008.01886.x (DOI)
Tilgjengelig fra: 2009-06-05 Laget: 2009-06-05 Sist oppdatert: 2009-06-05
Winquist, F., Krantz-Rülcher, C., Olsson, T. & Jonsson , A. (2009). Measurements of cadmium in soil extracts using multi-variate data analysis and electrochemical sensors. PRECISION AGRICULTURE, 10(3), 231-246
Åpne denne publikasjonen i ny fane eller vindu >>Measurements of cadmium in soil extracts using multi-variate data analysis and electrochemical sensors
2009 (engelsk)Inngår i: PRECISION AGRICULTURE, ISSN 1385-2256 , Vol. 10, nr 3, s. 231-246Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

There is a growing awareness of potential health risks due to exposure to heavy metals. One source of uptake is via agriculture, when heavy metals in the soil are taken up by the crop. The metal cadmium holds a special position, since it is considered to be a health risk, even at the low concentrations observed in our food supply, furthermore, it is ranked as eight on the top 20 hazardous substances list. Two measurement systems are described based on stripping voltammetry for analysis of cadmium. One is based on a three metal direct probe system (TMDPS) with three working electrodes (platinum, gold and rhodium), combined with a polishing unit, the other is an automatic flow through system, using one working electrode of gold, also equipped with a polishing unit. A number of different soils were extracted with an ammonium-lactate solution and analyzed with the systems, and the data obtained were subjected to multi-variate data analysis (MVDA). Using modeling based on partial least square (PLS), concentrations of cadmium in the soil extracts could be predicted for the TMDPS in the concentration area 0.5-10 mu g/l with a root mean square error of prediction (RMSEP) of 0.8 mu g/l and a relative predicted deviation (RPV) of 2.0. One sample could be analyzed in 4 min. It was also shown that by using different PLS models, the concentration of the elements copper, aluminum, lead and iron could be predicted. The possibilities of using the technique for field use were also evaluated by studies of mixtures of different soils in 0.1 M HNO3 solution, the time for an analysis was, however, rather large, around 20 min.

Emneord
Cadmium, Stripping voltammetry, Multi-variate data analysis, Soil, Soil extracts
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-17699 (URN)10.1007/s11119-008-9094-9 (DOI)
Tilgjengelig fra: 2009-04-16 Laget: 2009-04-14 Sist oppdatert: 2009-04-16
Winquist, F., Krantz-Rülcher, C. & Lundström, I. (2008). A miniaturized voltammetric electronic tongue. Analytical Letters, 41(5), 917-924
Åpne denne publikasjonen i ny fane eller vindu >>A miniaturized voltammetric electronic tongue
2008 (engelsk)Inngår i: Analytical Letters, ISSN 0003-2719, E-ISSN 1532-236X, Vol. 41, nr 5, s. 917-924Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

A miniaturized electronic tongue based on pulsed voltammetry has been developed. It was made by inserting three types of wires acting as working electrodes (gold, platinum, and rhodium, diameter 0.25 mm) into a platinum tube acting as a counter electrode (diameter 2 mm, length 4 mm). The arrangement was connected to a potentiostat controlled by a computer. Due to the small size of the miniaturized electronic tongue, and since no reference electrode is used, the setup is very simple and convenient. In order to characterize the analytical possibilities of the miniaturized electronic tongue, some initial experiments were performed. These include the determination of trace amounts of cadmium and lead (in the µM range) in 5 µL samples. Furthermore, the setup was placed under the real tongue of a volunteer to follow saliva composition during exercise. Copyright © Taylor & Francis Group, LLC.

Emneord
Electronic tongue, Miniaturized, Multivariate data analysis, Voltammetry
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-47211 (URN)10.1080/00032710801934809 (DOI)
Tilgjengelig fra: 2009-10-11 Laget: 2009-10-11 Sist oppdatert: 2017-12-13
Francioso, L., Bjorklund, R., Krantz-Rülcker, T. & Siciliano, P. (2007). Classification of multiple defect concentrations in white wine by platinum microelectrode voltammetry. Sensors and actuators. B, Chemical, 125(2), 462-467
Åpne denne publikasjonen i ny fane eller vindu >>Classification of multiple defect concentrations in white wine by platinum microelectrode voltammetry
2007 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 125, nr 2, s. 462-467Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Concentrations of defect pairs added to a white wine were classified by voltammetric measurements on interdigitated platinum microelectrodes using principal component analysis of the current responses. Combinations of 0, 1, 2 and 3 mM concentrations were investigated. The defect pair ascorbic acid/acetaldehyde exhibited little interaction with each other and the pair-wise concentrations were symmetrically positioned in a score plot around a center axis of equimolar concentrations. The ascorbic acid/sulfur dioxide pair exhibited a center axis for the equimolar concentrations shifted toward the 3 mM sulfur dioxide sample. The defect pair having the strongest interaction through complex formation, acetaldehyde/sulfur dioxide, had the equimolar concentrations in score plots located near the white wine control sample. © 2007 Elsevier B.V. All rights reserved.

HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-39611 (URN)10.1016/j.snb.2007.02.040 (DOI)50226 (Lokal ID)50226 (Arkivnummer)50226 (OAI)
Tilgjengelig fra: 2009-10-10 Laget: 2009-10-10 Sist oppdatert: 2017-12-13
Ulrich, C., Petersson, H., Sundgren, H., Björefors, F. & Krantz-Rülcker, C. (2007). Simultaneous estimation of soot and diesel contamination in engine oil using electrochemical impedance spectroscopy. Sensors and actuators. B, Chemical, 127(2), 613-618
Åpne denne publikasjonen i ny fane eller vindu >>Simultaneous estimation of soot and diesel contamination in engine oil using electrochemical impedance spectroscopy
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2007 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 127, nr 2, s. 613-618Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In this paper, we explore the combination of electrochemical impedance spectroscopy and multivariate data analysis to simultaneously predict the concentrations of soot and diesel in engine oil. For this purpose, we use a well defined measurement set-up to minimize interference from ambient noise, and to obtain a large amount of data in a short period of time. An imperative requirement is that soot and diesel affect the impedance in different ways over the employed frequency range. It was, for example, found that diesel had a larger influence at lower frequencies. Using partial least squares modelling we show that it is possible to simultaneously predict the concentrations of both soot and diesel in engine oil. Since the temperature in an engine varies, the influence of the oil temperature is investigated in a preliminary experiment. This study is a part of the development of an electrochemical on-board sensor for real-time monitoring of engine oil.

Emneord
Electrochemical impedance spectroscopy, Multivariate data analysis, Engine oil; Diesel, Soot
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-14886 (URN)10.1016/j.snb.2007.05.014 (DOI)
Tilgjengelig fra: 2008-09-29 Laget: 2008-09-29 Sist oppdatert: 2017-12-13
Lundström, I., Sundgren, H., Winquist, F., Eriksson, M., Krantz-Rülcker, T. & Lloyd-Spets, A. (2007). Twenty-five years of field effect gas sensor research in Linköping. Sensors and actuators. B, Chemical, 121(1), 247-262
Åpne denne publikasjonen i ny fane eller vindu >>Twenty-five years of field effect gas sensor research in Linköping
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2007 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 121, nr 1, s. 247-262Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The present contribution contains an overview of the development of gas sensitive field-effect devices in Linköping during the last 25 years. It is completely centred to the work at the Laboratory of Applied Physics at Linköping University, and is therefore not a proper review of a research field where many important contributions have been made by several other research groups. © 2006 Elsevier B.V. All rights reserved.

HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-37502 (URN)10.1016/j.snb.2006.09.046 (DOI)36430 (Lokal ID)36430 (Arkivnummer)36430 (OAI)
Tilgjengelig fra: 2009-10-10 Laget: 2009-10-10 Sist oppdatert: 2017-12-13
Gutes, A., Cespedes, F., del, V. M., Louthander, D., Krantz-Rülcher, C. & Winquist, F. (2006). A flow injection voltammetric electronic tongue applied to paper mill industrial waters. Sensors and actuators. B, Chemical, 115(1), 390-395
Åpne denne publikasjonen i ny fane eller vindu >>A flow injection voltammetric electronic tongue applied to paper mill industrial waters
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2006 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 115, nr 1, s. 390-395Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

A voltammetric electronic tongue with automated operation based on the flow injection (FIA) technique was applied to the characterization of wastewaters coming from the paper mill industry. A metallic multielectrode array - formed by platinum, gold and rhodium electrodes - was employed as the detection system, while the measurements were based on large amplitude pulse voltammetry (LAPV). LAPV consisted in scans of pulses from to 0 to 1.8 V at 0.2 V steps. Five current values were recorded for each pulse, so a set of 300 current values (three electrodes × 20 pulses × five values) was recorded for each sample. Samples were first discriminated using Principal Component Analysis (PCA), while Artificial Neural Networks were used for the characterization and prediction of chemical oxygen demand, conductivity and pH. The system may be used for the quick identification and monitoring of the quality of used waters in these industrial facilities. © 2005 Elsevier B.V. All rights reserved.

Emneord
Chemical oxygen demand, Electronic tongue, Flow injection analysis, Paper mill industry, Voltammetry
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-50077 (URN)10.1016/j.snb.2005.09.024 (DOI)
Tilgjengelig fra: 2009-10-11 Laget: 2009-10-11 Sist oppdatert: 2017-12-12
Ivarsson, P., Krantz-Rülcher, C., Winquist, F. & Lundström, I. (2005). A voltammetric electronic tongue. Chemical Senses, 30, I258-i259
Åpne denne publikasjonen i ny fane eller vindu >>A voltammetric electronic tongue
2005 (engelsk)Inngår i: Chemical Senses, ISSN 0379-864X, E-ISSN 1464-3553, Vol. 30, s. I258-i259Artikkel i tidsskrift (Fagfellevurdert) Published
Emneord
artificial sense, electronic tongue, multivariate data analysis, process supervision
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-46134 (URN)10.1093/chemse/bjh213 (DOI)
Tilgjengelig fra: 2009-10-11 Laget: 2009-10-11 Sist oppdatert: 2017-12-13
Winquist, F., Bjorklund, R., Krantz-Rülcher, C., Lundström, I., Ostergren, K. & Skoglund, T. (2005). An electronic tongue in the dairy industry. Sensors and actuators. B, Chemical, 111, 299-304
Åpne denne publikasjonen i ny fane eller vindu >>An electronic tongue in the dairy industry
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2005 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 111, s. 299-304Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The concept of electronic tongues or taste sensors has developed rapidly during recent years due to their large potential. They are based on electrochemical sensors combined with multivariate data analysis. Voltammetric electronic tongues have proven valuable in many applications. Due to their ruggedness and simplicity, they have been found especially suitable for on-line monitoring of industrial processes. A voltammetric electronic tongue, specially designed for use in the dairy industry is described. It consisted of four working electrodes (gold, platinum, rhodium and stainless steel), embedded in PEEK (TM). It was mounted in a housing of stainless steel, which was inserted in the process line for direct on-line measurements. The voltammetric electronic tongue was used to follow different sources of milk coming into the process and to monitor the cleaning process. (c) 2005 Elsevier B.V. All rights reserved.

Emneord
electronic tongue, taste sensor, dairy industry, voltammetry
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-46067 (URN)10.1016/j.snb.2005.05.003 (DOI)
Tilgjengelig fra: 2009-10-11 Laget: 2009-10-11 Sist oppdatert: 2017-12-13
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