TY - CONF A1 - Bolz, Axel A1 - Rurack, Knut A1 - Buurman, Merwe T1 - Microfluidic Paper-Based Analytical Devices with Surface Enhanced Raman Scattering Detection N2 - Microfluidic paper-based analytical devices (μPADs) in combination with surface enhanced Raman scattering (SERS) provide a way for analyses of complex mixtures. The μPADs can be used for the chromatographic separation of different compounds of mixtures in combination with the separate detection of the analytes in different zones on the paper by SERS. SERS allows to observe analytes directly without labelling in low concentrations in aqueous solutions and to identify them by their spectral fingerprint. SERS substrates on the μPADs were created by drying standard silver nanoparticle (AgNP) solution on the paper. The microfluidic structure of the μPADs was prepared by wax printing. As a model system, an aqueous solution of the non-fluorescent analyte adenine and two fluorescent dyes tris(2,2’-bipyridyl)dichlororuthenium(II) and sulforhodamine B was tested. The dependency of the SERS signal intensity on the analyte concentration can be fitted using a Langmuir isotherm curve progression. With this approach, a semi-quantitative analysis of the components is possible. The reproducibility and stability of the measurement procedure was tested with several measurements over time, different NP batches, and with different analytes in different concentrations and resulted in an average relative standard deviation of 16 %. The SERS spectra of the mixture of the model system are dominated by one compound depending on the concentration ratio. For the detection and identification of all components of the mixture, the compounds were therefore separated on the μPADs and measured at different positions. The position of adenine on the μPADs is dependent on the AgNP coverage of the paper. Due to this effect, it possible to detect adenine on a defined point on the μPADs and to get an information on the concentration in a mixture of three components. T2 - 30. Tag der Chemie Humboldt-Universität zu Berlin CY - Berlin, Germany DA - 05.07.2017 KW - SERS KW - µPAD PY - 2017 AN - OPUS4-42265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bolz, Axel A1 - Panne, Ulrich A1 - Rurack, Knut A1 - Buurman, Merwe T1 - Microfluidic paper strips for SERS analysis N2 - Surface enhanced Raman scattering (SERS) is a fast and sensitive spectroscopic method for the identification of analytes. With available portable Raman spectrometers, on-site analysis is possible. However, for on-site analysis, SERS substrates, which are cheap, easy to prepare, and simple in sample handling are necessary. Relevant analytes in the addressable concentration region for SERS are e.g. antibiotics and pesticides. Here, we present paper-based test strips for SERS analysis which are coated with silver nanoparticles. The coating was realized with different deposition methods of nanoparticle solutions. The papers were also functionalised with hydrophobic barriers to create μPADs. The strips were tested with selected analytes (e.g., adenine, rhodamine-6G) over a broad concentration range. The focus of our study lay on reproducibility and optimum SERS signal intensity. For the quantification of analytes, highly reproducible signal intensities are necessary. We have realized this reproducibility in acceptable quality. Moreover, employing intensity vs concentration calibration for the analytes, data analysis revealed a behaviour that was best described by a Langmuir isotherm, stressing the strong distance dependence of the SERS effect. For a fast and reproducible analysis of the data, a Labview program was finally compiled, which was fed with the calibration data and derived the concentration of analyte unknowns accordingly. T2 - 5. Berliner Chemie Symposium & 1. Chemie in Praxis CY - Berlin, Germany DA - 12.04.2016 KW - SERS KW - Raman KW - Paper PY - 2016 AN - OPUS4-36031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bolz, Axel A1 - Buurman, Merwe A1 - Panne, Ulrich T1 - Paper Test Strips with SERS detection for chemical analysis T2 - 4. Berliner Chemie Symposium T2 - 4. Berliner Chemie Symposium CY - Berlin, Germany DA - 2015-04-09 PY - 2015 AN - OPUS4-33747 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bolz, Axel A1 - Panne, Ulrich A1 - Buurman, Merwe T1 - SERS Detection on Pater Test Stripes T2 - Anakon 2015 T2 - Anakon 2015 CY - Graz, Österreich DA - 2015-03-23 PY - 2015 AN - OPUS4-33746 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bolz, Axel A1 - Buurman, Merwe A1 - Panne, Ulrich T1 - Test strips for SERS measurements T2 - 3. Doktorandenseminar des DAAS - Spektroskopie und Spurenanalytik T2 - 3. Doktorandenseminar des DAAS - Spektroskopie und Spurenanalytik CY - Münster DA - 2014-09-22 PY - 2014 AN - OPUS4-32299 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bolz, Axel A1 - Panne, Ulrich A1 - Rurack, Knut A1 - Buurman, Merwe T1 - SERS microfluidic paper-based analytical devices N2 - The fast identification and quantification of analytes in the field of food safety or environmental analysis is difficult. Surface enhanced Raman scattering (SERS) is an analytical method which can be used simultaneously for the rapid identification and concentration determination of trace analytes,[1,2] usually covering a large dynamic range from nanomolar up to molar concentrations. The identification of the molecules is accomplished through the specific fingerprint of a molecule’s Raman spectrum. For facile and straightforward SERS measurements, we present here a combination of paper-based SERS test strips with microfluidic systems on paper as a microfluidic paper-based analytical device (μPAD). The SERS μPAD is thus principally suited for cheap, fast, non-destructive, label-free and portable detection of analytes. In this system basically, the use of the microfluidic structured paper increases the sensitivity and suppresses background signals of the SERS assay. Deposition of the SERS substrate on the test strips is simple and relies on an inkjet printer. For the optimization of the reproducibility and intensity of the SERS signal, we tested different nanoparticles, different numbers of print cycles and different paper types. The nanoparticle solutions used in the μPAD preparation were gold and silver nanoparticle solutions. The paper types were cellulose and glass fiber. SERS arrays were prepared by printing and compared to arrays prepared by spraying. The optimized μPAD was used for the identification and quantification of pure analyte solutions (e.g., adenine) and mixtures of compounds, the concentration series following Langmuir isotherms. Relevant analytes in the field of food safety are antibiotics and pesticides. We apply the SERS microfluidic paper-based analytical devices for the detection of antibiotics (enoxacin, enrofloxacin) and pesticides. T2 - Europtrode XIII CY - Graz, Austria DA - 20.03.2016 KW - SERS KW - Paper PY - 2016 AN - OPUS4-35702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bolz, Axel A1 - Panne, Ulrich A1 - Rurack, Knut A1 - Buurman, Merwe T1 - Paper-based SERS test strips N2 - For the non-destructive chemical analysis of organic compounds, several different methods such as NMR, UV-vis absorption, IR, Raman, or fluorescence spectroscopy are available. However, all available methods have some restrictions such as the necessity of a large sample amount, interferences in the presence of water, or overlapping signals from the analytes or matrix. Surface enhanced Raman scattering (SERS) allows to observe analytes directly without labelling in low concentrations in aqueous solutions and to identify them by their spectral fingerprint. Therefore, in this work we use SERS as a detection method for different analytes in low concentrations in combination with paper-based test strips as SERS substrates and for sample preparation. We present a spray method for the preparation of SERS test stripes.[1] With this spray method, nanoparticle solution was deposited on cellulose and glass fibre paper as SERS substrate. The prepared paper-based test strips were tested with classical SERS reporter molecules, e.g. rhodamine 6G, 4-aminothiophenol, and adenine. For the quantification of analytes, highly reproducible signal intensities are necessary, which can be realized with the test strips in acceptable quality. Moreover, employing intensity vs concentration calibration for the analytes, data analysis revealed a behaviour that was best described by a Langmuir isotherm, stressing the strong distance dependence of the SERS effect. For an easier identification of analytes in a mixture of compounds, the paper-based test strips were functionalised with hydrophobic barriers by wax printing. With these microfluidic paper-based analytical devices (µPAD) the sample mixture can be separated by the chromatographic effects of the paper and the different analytes can be separately detected and identified by SERS. [1] A. Bolz, U. Panne, K. Rurack, M. Buurman, Glass fibre paper-based test strips for sensitive SERS sensing, Anal. Methods, 2016, 8, 1313-1318. T2 - International RamanFest 2016 CY - Berlin, Germany DA - 19.05.2016 KW - SERS KW - Raman KW - Paper PY - 2016 AN - OPUS4-36726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bolz, Axel A1 - Panne, Ulrich A1 - Rurack, Knut A1 - Buurman, Merwe T1 - Glass fibre paper-based test strips for sensitive SERS sensing JF - Analytical Methods N2 - We present paper-based test strips for chemical sensing with surface enhanced Raman scattering as detection method. The test strips are prepared on glass fibre paper with silver nanoparticles and a spray method with an airbrush spray setup as a low cost fabrication approach. The properties of the test strips are investigated with three classical Raman analytes rhodamine 6G, 4-aminothiophenol and adenine and optimized for a good reproducibility of the intensity measurements. All test analytes can be identified at low concentrations. For adenine, a concentration series from 10⁻⁴ M to 10⁻⁸ M is measured and the calibration data can be fitted and evaluated with a Langmuir isotherm model. The optimized test strips are applied for the identification of two antibiotics enoxacin and enrofloxacin. KW - surface enhanced Raman scattering KW - glass fibre paper KW - sensing KW - spray KW - Langmuir isotherm PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354878 DO - https://doi.org/10.1039/C5AY03096J SN - 1759-9660 VL - 8 IS - 6 SP - 1313 EP - 1318 PB - The Royal Society of Chemistry AN - OPUS4-35487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -