TY - JOUR A1 - Czolkos, Ilja A1 - Dock, Eva A1 - Tonning, Erik A1 - Christensen, Jakob A1 - Winther-Nielsen, Margrethe A1 - Carlsson, Charlotte A1 - Mojzikova, Renata A1 - Skladal, Petr A1 - Wollenberger, Ursula A1 - Norgaard, Lars A1 - Ruzgas, Tautgirdas A1 - Emneus, Jenny T1 - Prediction of wastewater quality using amperometric bioelectronic tongues JF - Marine policy N2 - Wastewater samples from a Swedish chemi-thermo-mechanical pulp (CTMP) mill collected at different purification stages in a wastewater treatment plant (WWTP) were analyzed with an amperometric enzyme-based biosensor array in a flow-injection system. In order to resolve the complex composition of the wastewater, the array consists of several sensing elements which yield a multidimensional response. We used principal component analysis (PCA) to decompose the array's responses, and found that wastewater with different degrees of pollution can be differentiated. With the help of partial least squares regression (PLS-R), we could link the sensor responses to the toxicity parameter, as well as to global organic pollution parameters (COD, BOD, and TOC). From investigating the influences of individual sensors in the array, it was found that the best models were in most cases obtained when all sensors in the array were included in the PLS-R model. We find that fast simultaneous determination of several global environmental parameters characterizing wastewaters is possible with this kind of biosensor array, in particular because of the link between the sensor responses and the biological effect onto the ecosystem into which the wastewater would be released. In conjunction with multivariate data analysis tools, there is strong potential to reduce the total time until a result is yielded from days to a few minutes. KW - Biosensor array KW - Electronic tongue KW - Amperometric sensor KW - Screen-printed electrode KW - Multivariate data analysis KW - Chemometrics KW - Wastewater KW - Toxicity KW - Phenolic compounds Y1 - 2016 U6 - https://doi.org/10.1016/j.bios.2015.08.055 SN - 0956-5663 SN - 1873-4235 VL - 75 SP - 375 EP - 382 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Rühlmann, Madlen A1 - Büchele, Dominique A1 - Ostermann, Markus A1 - Bald, Ilko A1 - Schmid, Thomas T1 - Challenges in the quantification of nutrients in soils using laser-induced breakdown spectroscopy BT - a case study with calcium JF - Spectrochimica Acta Part B: Atomic Spectroscopy N2 - The quantification of the elemental content in soils with laser-induced breakdown spectroscopy (LIBS) is challenging because of matrix effects strongly influencing the plasma formation and LIBS signal. Furthermore, soil heterogeneity at the micrometre scale can affect the accuracy of analytical results. In this paper, the impact of univariate and multivariate data evaluation approaches on the quantification of nutrients in soil is discussed. Exemplarily, results for calcium are shown, which reflect trends also observed for other elements like magnesium, silicon and iron. For the calibration models, 16 certified reference soils were used. With univariate and multivariate approaches, the calcium mass fractions in 60 soils from different testing grounds in Germany were calculated. The latter approach consisted of a principal component analysis (PCA) of adequately pre-treated data for classification and identification of outliers, followed by partial least squares regression (PLSR) for quantification. For validation, the soils were also characterised with inductively coupled plasma optical emission spectroscopy (ICP OES) and X-ray fluorescence (XRF) analysis. Deviations between the LIBS quantification results and the reference analytical results are discussed. KW - Laser-induced breakdown spectroscopy (LIBS) KW - Soil KW - Multivariate data analysis KW - Principal component analysis (PCA) KW - Partial least squares regression (PLSR) Y1 - 2018 U6 - https://doi.org/10.1016/j.sab.2018.05.003 SN - 0584-8547 VL - 146 SP - 115 EP - 121 PB - Elsevier CY - Oxford ER -