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Guenther Proll

Publications and source records attributed to Guenther Proll.

7 recordsLinked to original sources
PubMed2005

Improved strategy for biosensor-based monitoring of water bodies with diverse organic carbon levels.

To protect water resources and to control the water quality it is necessary to develop fast, sensitive, cost-effective, and easy-to-use analytical systems, which are able to measure a variety of contaminants in water. Monitoring water bodies with various matrices can be very difficult. The diverse organic carbon level in water samples (e.g. river water or seawater) causes problems at common analysis and in particular at immunological methods. Here, we demonstrate a new method to overcome the partly occurring matrix problems at quasi-continuous real-world biosensor monitoring. Therefore, we developed an easy matrix referencing method for our fully automated immunoassays that could be adapted to other applications depending on a similar test-format. The method was developed using a synthetic organic carbon standard, and validated using a diluted turf extract. Results for the ultra-sensitive immunoassay for estrone quantification are shown as example. The developed method was verified using immunoassays for testosterone, progesterone, ethinylestradiol, estradiol, and estriol.

Algorithms↗
PubMed2005

Automated water analyser computer supported system (AWACSS) Part I: Project objectives, basic technology, immunoassay development, software design and networking.

A novel analytical system AWACSS (automated water analyser computer-supported system) based on immunochemical technology has been developed that can measure several organic pollutants at low nanogram per litre level in a single few-minutes analysis without any prior sample pre-concentration nor pre-treatment steps. Having in mind actual needs of water-sector managers related to the implementation of the Drinking Water Directive (DWD) (98/83/EC, 1998) and Water Framework Directive WFD (2000/60/EC, 2000), drinking, ground, surface, and waste waters were major media used for the evaluation of the system performance. The instrument was equipped with remote control and surveillance facilities. The system's software allows for the internet-based networking between the measurement and control stations, global management, trend analysis, and early-warning applications. The experience of water laboratories has been utilised at the design of the instrument's hardware and software in order to make the system rugged and user-friendly. Several market surveys were conducted during the project to assess the applicability of the final system. A web-based AWACSS database was created for automated evaluation and storage of the obtained data in a format compatible with major databases of environmental organic pollutants in Europe. This first part article gives the reader an overview of the aims and scope of the AWACSS project as well as details about basic technology, immunoassays, software, and networking developed and utilised within the research project. The second part article reports on the system performance, first real sample measurements, and an international collaborative trial (inter-laboratory tests) to compare the biosensor with conventional anayltical methods.

Algorithms↗
PubMed2005

Automated Water Analyser Computer Supported System (AWACSS) Part II: Intelligent, remote-controlled, cost-effective, on-line, water-monitoring measurement system.

A novel analytical system AWACSS (Automated Water Analyser Computer Supported System) based on immunochemical technology has been evaluated that can measure several organic pollutants at low nanogram per litre level in a single few-minutes analysis without any prior sample pre-concentration or pre-treatment steps. Having in mind actual needs of water-sector managers related to the implementation of the Drinking Water Directive (DWD) [98/83/EC, 1998. Council Directive (98/83/EC) of 3 November 1998 relating to the quality of water intended for human consumption. Off. J. Eur. Commun. L330, 32-54] and Water Framework Directive (WFD) [2000/60/EC, 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Off. J. Eur. Commun. L327, 1-72], drinking, ground, surface, and waste waters were major media used for the evaluation of the system performance. The first part article gave the reader an overview of the aims and scope of the AWACSS project as well as details about basic technology, immunoassays, software, and networking developed and utilised within the research project. The second part reports on the system performance, first real sample measurements, and an international collaborative trial (inter-laboratory tests) to compare the biosensor with conventional anayltical methods. The systems' capability for analysing a wide range of environmental organic micro-pollutants, such as modern pesticides, endocrine disrupting compounds and pharmaceuticals in surface, ground, drinking and waste water is shown. In addition, a protocol using reconstitution of extracts of solid samples, developed and applied for analysis of river sediments and food samples, is presented. Finally, the overall performance of the AWACSS system in comparison to the conventional analytical techniques, which included liquid and gas chromatographic systems with diode-array UV and mass spectrometric detectors, was successfully tested in an inter-laboratory collaborative trial among six project partners.

Algorithms↗
PubMed2004

Verification of performance with the automated direct optical TIRF immunosensor (River Analyser) in single and multi-analyte assays with real water samples.

In order to verify the reproducibility, precision, and robustness of the optical immunosensor River Analyser (RIANA), we investigated two common statistical methods to evaluate the limit of detection (LOD) and the limit of quantification (LOQ). Therefore, we performed a simultaneous multi-analyte calibration with atrazine, bisphenol A, and estrone in Milli-Q water. Using an automated biosensor, it was possible for the first time to achieve a LOD below 0.020 microg L(-1) using a common statistically based method without sample pre-treatment and pre-concentration for each of the analytes in a simultaneous multi-analyte calibration. This biosensor setup shows values comparable to those obtained by more classical analytical methods. Based on this calibration, we measured spiked and un-spiked real water samples with complex matrices (samples from different water bodies, from ground water sources, and tap water samples). The comparison between our River Analyser and common analytical methods (like GC-MS and HPLC-DAD) shows overall comparable values for all three analytes. Furthermore, a calibration of isoproturon (IPU) (in single analyte mode) resulted in a LOD of 0.016 microg L(-1), and a LOQ of 0.091 microg L(-1). In compliance with guidelines of the Association of Analytical Communities International (AOAC), six out of nine recovery rates (recovery rate: measured concentration divided by real concentration in percent) for three surface water samples with different matrices (spiked and un-spiked) could be obtained between 70 and 120% (recovery rates between 70 and 120%, as demanded by the guidelines of the AOAC International). The reproducibility was checked by measuring replica of each sample within independent repetitions. Robustness could be demonstrated by long-term stability tests of the biosensor surface. These studies show that the biosensor used offers the necessary reproducibility, precision, and robustness required for an analytical method.

Atrazine↗
PubMed2004

Ultra-sensitive fully automated immunoassay for detection of propanil in aqueous samples: steps of progress toward sub-nanogram per liter detection.

The widely-used pesticide propanil is a selective post-emergent general-use acetanilide herbicide registered for control of broadleaf and grass weeds in rice, small grain, and turf. Because broad application and quite heavy use of this herbicide lead to contaminated sites and, consequently, contaminated water, immunoanalytical methods with very low limits of detection (LOD) and low limits of quantification (LOQ) are becoming increasingly important for environmental analysis and, especially, for monitoring drinking-water quality. Environmental monitoring of pesticides, hormones, endocrine-disrupting chemicals, and antibiotics in aqueous samples (e.g. surface, ground, waste, or drinking water) with quite difficult matrices places large demands on chemical analysis. Biosensors have suitable characteristics such as efficiency in enabling very fast, sensitive, and cost-effective detection. Here we describe the steps of progress toward sub-nanogram per liter detection of propanil with a fully automated immunoassay. In contrast with common analytical methods such as GC-MS or HPLC-MS the biosensor used requires no sample pre-treatment and pre-concentration. The basis of our sensitive assay is an antibody with a high affinity constant toward propanil. During the optimization process, we compared different surface modifications (four different immobilized derivatives) and reduced the amount of antibody per sample. In fact, optimization of the assay resulted in an LOD of 0.6 ng L(-1) and an LOQ of 4.5 ng L(-1) without any sample pre-treatment and without pre-concentration. These results for propanil with the RIANA instrument, and its improved sensitivity for detection of a single pesticide at the low nanogram per liter range, show that biosensors can compete with common analytical methods in the field of water analysis.

Autoanalysis↗
PubMed2003

Immunosensor for estrone with an equal limit of detection as common analytical methods.

Immunoanalytical methods at a very low limit of detection (LOD) and a low limit of quantification (LOQ) are becoming more and more important for environmental analysis and especially for monitoring drinking water quality. Biosensors have suitable characteristics such as efficiency in allowing very fast, sensitive, and cost-effective detection. Here we describe a fully automated immunoassay for estrone with a LOD below 0.20 ng L(-1) and a LOQ below 1.40 ng L(-1). In contrast to common analytical methods such as GC-MS or HPLC-MS, the biosensor used requires no sample pre-treatment and pre-concentration. The basis of our sensitive assay is the antibody with a high affinity constant towards estrone. The very low amount of antibody per sample results in low validation parameters (LOD, LOQ, and IC50), but this assay for estrone represents the current device-related limitation of the River Analyser (RIANA).

Automation↗