Hernandezalstrup2076

The specific interaction was confirmed with control experiments, electrodes containing only PEI or SF, that no significant changes in the voltammogram responses were observed and principal component analysis confirmed these results. The films formation and response were verified using scanning electronic microscopy (SEM). The developed immunosensor seems to be a promising and effective early complementary exam to assist in the VTE diagnosis, through the combined response of two biomarkers very sensible.The sensitivity of a spectrophotometric assay is enhanced either by increasing the concentration of the target molecules within the flow cell or by extending the length of the light path of the flow cell. Determination of nutrients at nanomolar concentrations in sea water has therefore been based either on the preconcentration of the analyte on a microcolumn from a large volume of sample followed by its elution into a conventional 1-2 cm flow cell, or by the use of Liquid Core Waveguide (LCW) with a light path as long as several meters. In order to evaluate the relative improvements of these different approaches to increasing sensitivity we have developed a preconcentration technique for the determination of nitrite in seawater using the Gries reaction and compare its sensitivity and precision to that of non preconcentration techniques using both LCW and Linear Light Path (LLP) cells of different lengths. In this work the performance of the LLP is investigated and compared with the performance of the coiled LCW flow cell. Next, the determination of nitrite, automated by programmable Flow Injection (pFI), was carried out by using LCW and LLP flow cells, as well as by using a 10 cm LLP flow cell together with the preconcentration step of nitrite on a microcolumn. The assay of nitrite in sub micromolar range was most efficiently performed by a combination of pFI with the LLP flow cell without the need for a preconcentration step. The determination was performed at a rate of 40 samples/hour with a Limit of Detection (LOD) = 0.6 nM N using a 50 cm long, and a LOD = 2.5 nM N using a 10 cm long, LLP flow cell. Analysis of sea water samples confirmed that salinity does not affect the sensitivity of the determination. At a much lower cost than LCW, the LLP flow cell can also be easily assembled from components usually at hand in a laboratory.The rare earth elements (REE) composition in Fe-mineral phases is an important tool in iron formation studies to obtain information about parent rocks and environmental and paragenetic processes. However, the determination of REE presents some difficulties, such as the low concentration of these elements, matrix complexity and lack of iron matrix certified reference materials. The aim of the present work is to propose an analytical method to determine the REE plus Y (REE + Y) contents at trace levels in Fe-(hydr)oxides by the laser ablation ICP-quadrupoleMS technique, using external calibration. The calibration curves were obtained from analyses of reference materials with different matrices, and the analytical conditions were checked on the NIST 614 glass. The linearity (R2 ≥ 0.98), limit of detection (0.002-0.044 μg g-1), limit of quantification (0.008-0.146 μg g-1), recovery (88.4-112.4%), and intraday (0.1-14.1%) and interday (1.6-17.8%) precision were systematically assessed. The results obtained showed that the method is fit for the purpose and showed evidence of a nonsignificant interference of the matrix. Thus, the developed procedure was applied in the analyses of magnetite, martite, hematite, and goethite grains from Cauê Iron Formation (Brazil). The REE + Y patterns of the minerals are consistent with the previous study of bulk analyses on whole rocks and highlight the postdepositional signature of these elements in banded iron formations.This research reports on the development of a method to identify and quantify fungal biomass based on ergosterol autofluorescence using excitation-emission matrix (EEM) measurements. In the first stage of this work, several ergosterol extraction methods were evaluated by APCI-MS, where the ultrasound-assisted procedure showed the best results. Following an experimental design, various quantities of the dried mycelium of the fungus Schizophyllum commune were mixed with the starchy solid residue (BBR) from the babassu (Orbignya sp.) oil industry, and these samples were subjected to several ergosterol extraction methods. The EEM spectral data of the samples were subjected to Principal Component Analysis (PCA), which showed the possibility to qualitatively evaluate the presence of ergosterol in the samples by ergosterol autofluorescence without the addition of any reagent. In order to assess the feasibility of quantifying fungal biomass using ergosterol autofluorescence, the EEM spectral data and known amounts of in this case BBR.Novel supramolecular gelators based on quinoline-indolin-2-one structure were synthesized. These gelators formed stable organogels in a mixture of DMSO/H2O (11). The scanning electron microscopy (SEM), IR and NMR spectroscopies, and rheological measurements were used to study the properties of the gels. Among the synthesized compounds, G2 was chosen as the best gelator and utilized as a naked eye chemosensor for the selective detection of Cu2+ and Hg2+ ions alongside and CN‾ ion as toxic and hazardous materials. The gelator G2 was selectively transformed into a sol state in the presence of Cu2+ ion alongside with a vivid change of color from orange to cherry red. Hg2+ ion showed a notable change in color from orange to brick red, but the gel state remained intact. MIRA-1 datasheet The detection limit for the gelator G2 toward Cu2+and Hg2+ were 7.25 × 10-6 mol. L-1 and 4.80 × 10-6 mol. L-1 respectively. All the tested anions had no distinct effect on the gel state and/or the color of G2, while, in the presence of CN‾, although the gel state was again unchanged a drastic color change from orange to dark purple was observed. The detection limit for G2 toward CN- was 1.36 × 10-4 mol. L-1. The gelator G2 also operated simultaneously the roles of INH and OR gates in which water, Hg2+, Cu2+ ions are inputs, and the gel state and absorbance around 600 nm (color change) are outputs.