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The extracts recovered from the devices were analyzed by gas chromatography (GC), resulting in the identification and quantification of DEP (0.697-13.7 ng L-1), DiBP (0.100-4.43 ng L-1), DBP (0.014-1.21 ng L-1), BBP (0.218-5.67 ng L-1), and DEHP (0.002-2.24 ng L-1). Despite being frequently identified, DEHP concentrations were well below the maximum established limits, revealing a good water quality in terms of the target PAEs. In contrast, screening the extracts using GCxGC was possible to detect other hazardous pollutants such as pesticides, drugs, and their metabolites. The described device was effective and reliable, providing accurate PAE measurements following short exposure periods. In this sense, its deployment during emergency operations, such as accidental discharges of industrial effluents into natural waters, could continuously and cost-effectively monitor water quality.Ochratoxin A (OTA) is one of the most prevalent and toxic mycotoxins. Ultrasensitive and convenient detection of OTA is urgent demanded for public health. In this work, a dual-readout immunoassay was established for the detection of OTA based on Ce4+ oxidizing 3,3',5,5'-tetramethylbenzidine (TMB) and Ce3+ inducing aggregation induced emission (AIE) of Au nanoclusters (AuNCs). Under alkaline phosphatase (ALP), the ascorbic acid 2-phosphate (AA2P) can form ascorbic acid (AA) by dephosphorylation. The AA can reduce Ce4+ to generate Ce3+, which induced the AIE of AuNCs to enhance the fluorescence intensity of AuNCs. Meanwhile, unreacted Ce4+ oxidized TMB to form blue oxTMB. Thus, a dual-readout immunoassay was developed based on AIE of AuNCs and TMB as substrate. The limits of detection (LODs) were as low as 0.62 ng/mL for fluorescent assay and 0.81 ng/mL for colorimetric assay. The recoveries of OTA from corn were 94.4%-107.7% for the fluorescent mode and 93.7%-106.9% for the colorimetric mode. The results verified that the cerium ions triggered dual-readout immunoassay was reliable to sensitive detect OTA in corn samples.In this work, a small-size inbuilt-metal ceramic heater (IMCH) was for the first time utilized as a solid sampling electrothermal vaporizer (ETV), and then a novel direct sampling mercury analyzer coupled with a miniature atomic absorption spectrometer was thereby fabricated for sensitive determination of mercury in soil. The mercury analyzer is mainly composed of an IMCH-ETV, a catalytic pyrolysis furnace (CPF) using Al2O3 particles as a new filler, an atomic absorption spectrometer (AAS) and a miniature air pump for carrier gas; herein, the mostly used gold amalgamation was canceled. The IMCH with 30 W heating fulfills the 100% vaporization of mercury from up to 80 mg soil samples using 0.1 L min-1 air carrier. Under the optimized conditions, the method detection limit (LOD) was 0.4 ng g-1 for a 50 mg sample and the RSD of 11 repeated measurements of GSS-3a soil certified reference material (CRM) was 4%. Furthermore, the measured Hg values in various soil CRMs and real soil samples were within their certified values and consistent with that using the Chinese standard method (solid sampling catalytic pyrolysis AAS with gold amalgamation); and the recoveries were 85-113%, which proved favorable analytical accuracy and precision. This fabricated instrumentation only occupies 5 kg and 200 W power consumption vs. more than 25 kg and 1000 W for the traditional Hg analyzer. Therefore, the proposed IMCH-ETV-AAS method is very suitable for portable and rapid detection of mercury in soil.Refractive index detection (RID) is attractive because it allows approaching the benefits of universal detection with liquid chromatography, by which ideally standard independent calibration and hence compound independent quantification becomes possible. Nevertheless, the implementation of RID has remained limited as it offers poor detection sensitivity while only being compatible with isocratic mobile phases. The implementation of compositional solvent gradients has remained prohibitively challenging in commercial HPLC-RID systems due to the resulting drastic alterations in refractive index and extreme baseline drift. While the refractive index is also highly dependent on temperature, more leeway appears possible to mitigate the problem, particularly when the used temperature gradients can be limited. Temperature-responsive liquid chromatography (TRLC) allows obtaining isocratic reversed phase type of separations, whereby retention is modulated via temperature changes ∼ 15 °C-20 °C above and below the polymer conversion temperature. Elution profiles, reminiscent of what can be obtained with solvent gradients in conventional RPLC, can then be obtained by enacting downwards temperature gradients on the columns. This work comprises a proof-of-principle to illustrate the possibilities of combining thermal gradient TRLC with RID. The observed baseline drift appeared thereby very minor ( less then 5 nRIU min-1), and hence easily controllable. Short chain fatty acids are used as representative compounds to assess this new approach. Overlapping calibration lines are accordingly obtained for all fatty acids between butyric and decanoic acid.Imaging the distribution of metabolites is very powerful in diagnostics but it is also employed in fundamental research. Although NMR spectroscopy is well established for determining metabolic profiles of biological samples, its application is limited to magnetic resonance imaging that can produce images of larger structures, but the number of detectable metabolites is very low. Mass spectrometry imaging on the other hand is well established with pixel sizes in the μm range. This limits the analysis of larger structures like tissue sections and detection of metabolites depends on their ionization properties. JTZ-951 cost High resolution NMR metabolomics could complement these methods. However, this is prevented due to time consuming extraction procedures. To overcome these limitations, the following protocol was established and applied to two different ham slices sampling is directly done into the NMR tube and after extraction of polar and non-polar metabolites in the NMR tube, slice selective NMR spectra are acquired. Multivariate analysis (PCA) of the NMR-spectra and subsequent visualization of the differences correlate well with structures visible in the ham slices. The proposed protocol can be used for metabolic imaging and could complement other imaging methods.This study reports a facile approach for the fabrication of chitosan (CS, biopolymer)- and l-histidine (L-His, biomolecule)-stabilized self-assembled silicon nanoparticles (SiNPs) for sensing Cu2+ ions. Approached method yielded 3.8 ± 0.04 nm size CS/L-His-SiNPs particles, with high stability against harsh pH and temperature conditions. Besides, CS/L-His-SiNPs highly selective to Copper amongst different metal ions tested (Fe3+, Mg2+, Al3+, Cr3+, Cr6+, Cu2+, Mn2+, Cd2+, Pb2+, Zn2+, Hg2+, Ca2+, Li2+, Po42-, As3+, As5+). As compared to the blank-SiNPs (LOD = 96.49 ± 0.223 μM) and CS-SiNPs (LOD = 33.35 ± 1.004 μM); L-His ligand, enhanced the sensitivity of the CS/L-His-SiNPs toward Cu2+ with remarkable LOD value of 55.02 ± 0.42 nM. Applicability of CS/L-His-SiNPs was evaluated by coating CS/L-His-SiNPs on thin layer chromatography (TLC) sheets, CS/L-His-SiNPs-TLC sheets exhibited significant sensing capacity toward Cu2+ ions, with a detection range of 4.0-900 μM, making them suitable for on-site analysis of Cu2+ ions from both environmental and clinical samples. Finally, Cu2+ sensing practicality of CS/L-His-SiNPs-TLC sheets were challenged against real human urine samples. Expressively, CS/L-His-SiNPs-TLC sheets could be regenerated using ethylenediaminetetraacetic acid (EDTA), without losing their photostability, and can be reused further.Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems have been widely applied in nucleic acid analysis for the high specificity. Coupled with pre-amplification steps, the sensitivity of CRISPR-based detection is greatly improved. However, an extra pre-amplification step not only complicates the detection procedures but may also cause aerosol contaminations in the process of transferring amplified solution into CRISPR system. In this study, we demonstrate that combination of multiple crRNAs in CRISPR/Cas12a system can enhance the detection sensitivity. Based on it, we establish a multiple crRNAs enhanced CRISPR (meCRISPR) method and apply it to meat adulteration identification. Take cytochrome b (Cyt b) gene as a target, meCRISPR method can directly detect as low as 1.13 ng/μL extracted pork DNA and 5% (w/w) pork contamination in pork and beef meat mixtures. There is no cross-reaction with extracted chicken, beef, duck and fish DNA. meCRISPR reaction is incubated at an isothermal temperature, and the detection process can be completed in a designed portable apparatus with a heat block, a light emitting diode and filters. For the simplicity, specificity and sufficient sensitivity of meCRISPR method, it will have great prospects in species identification, food adulteration, and genetically modified food detection.In the current study, we have utilized semi-enclosed, leak-proof, microfluidic paper-based analytical devices (μPAD's) modified with isatin conjugated chitosan as specific colorimetric reagent for the detection of proline. Proline is one of the globally accepted stress biomarker in plants and also one of the prominent amino acid present in wine and some processed food. Quantification of proline is regularly required in agriculture field, food and wine industries. Specific interaction of isatin with proline, uniform film forming ability of chitosan which results in uniform coloration and the presence of leak-proof layer which prevent the diffusion of colorimetric reagent deeper resulted in enhancement of color signal intensity at the reaction zone were utilized. Further, the images of the μPAD's were captured using smartphone with 3D printed imaging box which houses smartphone and μPAD's. This platform utilizes smartphone flash for uniform illumination and ensures constant positioning of μPAD's to capture images. This greatly enhances the sensitivity and accuracy of our platform. Compared to previously published highly sensitive multi-layer, paper-based platform for detection of proline, current method has enhanced detection range (∼7 fold) and has comparable limit of detection of 23.75 μM. Moreover, the developed μPAD's platform has reduced optimum reaction temperature and time compared to previous work. The developed paper based platform was utilized for evaluation of proline content in young Arabidopsis plants which are subjected to water stress for 5 days. The devised paper-based methods have the potential to be applicable for the on-site evaluation of various stresses in plants.Potassium ion channels are expressed on the cell membranes, implicated in wide variety of cell functions and intimately linked to cancer cell behaviors. This work reports the first bioplatform described to date allowing simple and rapid detection of ion channel activity and the effect of their inhibitors in cancer cells. The methodology involves interrogation of the channel of interest from cells specifically captured on magnetic immunoconjugates using specific detection antibodies that are labeled with horseradish peroxidase enzyme. The channel activity is reflected by an amperometric signal transduction of the resulting magnetic bioconjugates onto screen-printed carbon electrodes. The bioplatform feasibility was proven for the detection of the Kv channels in U87 human glioblastoma cells and their blocking by scorpion venom KAaH1 and KAaH2 peptides. The obtained results confirm the high sensitivity (detection of 5 U87 cells⋅mL-1 and 0.06 μg mL-1 of KAaH2) of the proposed bioplatform and their versatility to detect both potassium channel activity and their potential inhibitors, in a given cancer cell line, with high sensitivity in a simple and fast way.