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Heavy metal poisoning is the most prevalent health hazard at hazardous waste sites, affecting a large population on daily basis, with arsenite poisoning ranking third in terms of prevalence and severity. Therefore, the main objective of this study is to develop a novel, highly efficient sensor for detecting trace amounts of arsenite (AsIII) in human serum by utilising reduced graphene oxide/gold nanoparticles (rGO/AuNPs) based nanocomposite structure. In this work, a screen-printed carbon electrode (SPE) was modified using rGO/AuNPs nanocomposite to detect AsIII in human serum. The detection data were recorded and analysed using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV), whereas transmission electron microscope (TEM), scanning electron microscope (SEM) as well as Fourier transform infrared (FTIR) spectroscopy were used to determine the surface morphological features and the presence of significant elements/groups in the prepared nanocomposite structure. Under the optimised conditions, the linear regression coefficient (R2) for the DPV response of the fabricated electrode (rGO/AuNPs@SPE) was observed to be 0.98. The rGO/AuNPs@SPE demonstrated remarkable sensor response for AsIII with detection limits of 10 ppb via DPV in standard samples, due to the synergistic effect of rGO and AuNPs based nanocomposite. The sensitivity of the sensor was found to be 0.0142 Appb−1cm−2 for 100–1000 ppb concentration range of AsIII. The rGO/AuNPs@SPE sensor also displayed good stability and reproducibility when used in AsIII spiked human serum samples in which the limit of detection was observed at 100ppb. The porous structure of rGO on the sensing interface efficiently improves the electrode's adsorption and conductivity, while citrate capped AuNPs offer the functional groups required for maximum adsorption of AsIII. Hence, the developed electrochemical sensor (rGO/AuNPs@SPE) can be used very precisely and reliably in various applications for trace level detection of AsIII in human serum. [ABSTRACT FROM AUTHOR]

The reported work presents an ultrafast and ultrasensitive sensing platform for the precise and reliable trace-level detection of Methyl nicotinate (MN) leading to early stage diagnosis of Tuberculosis (TB). The design and fabrication of the sensor was done using silicon nanowires (SiNWs) and titanium dioxide (TiO2) nanoparticles-based nanocomposite. The structural morphology and elemental analysis of the fabricated sensor were done using various characterization tools such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), Energy Dispersive X-Ray Analyzer (EDA) and X-ray diffraction (XRD). With a very precise limit of detection (LOD) (10 ppb), the sensor response was observed to be 1.02. The fabricated TiO2/SiNWs sensor demonstrates good accuracy and reproducibility along with very fast response and recovery time, i.e., ~20sec and ~30sec, respectively. Hence, the results reported in the present work and the developed sensing platform using TiO2/SiNWs nanocomposite could be utilized for reliable and precise identification of TB at an early stage. [ABSTRACT FROM AUTHOR]

Gas chromatography-mass spectrometry (GC-MS) method for detection of metformin in biological matrices is developed. Distinct derivatization techniques were employed for sample preparation for GC-MS analysis. N-methyl bis (trifluoroacetamide) [MBTFA] was found to be the best derivatization reagent for the GC-MS analysis of metformin. Total ion current (TIC) mode was selected for the monitoring of ions of trifluoroacetyl(TFA) derivative of metformin with m/z ratio of 303. Distinct parameters like specificity, carryover, stability, precision and accuracy were evaluated for validating the identification method. A novel Thin Layer Chromatography (TLC) method is also developed for the detection of metformin as a screening method. The GC-MS method is found to be linear and illustrated within the range 500ng/ml to 2500ng/ml with the value of R2 (coefficient of determination) at 0.9986. Retention time of derivatized metformin was found to be 4 minutes 2 seconds. Precision (%) for the interday and intraday analysis found to be in the respectable spectrum. Accuracy at each concentration level was within the ±15% of the nominal concentration. Henceforth, the proposed method can be employed for determination of metformin in biologicalmatrices. [ABSTRACT FROM AUTHOR]

The need of rapid, biocompatible and reusable nanotechnology for water purification is a leading global priority. In this article, we have synthesized polyaniline-impregnated nanocellulose (PANI-NC) composites. It is used not only for the removal of hexavalent chromium in aqueous media but also for cleaning of industrial waste water. The synthesized PANI-NC composites were characterized by blend of characterization tools such as DLS, SEM and FTIR, while adsorption studies were recorded by flame AAS. The PANI-NC nanocomposite was used in different forms like powder and pebbles either in free form or packed in a tea bag or a continues column to make ready to use, user-friendly system. Our PANI-NC-based system provides the 92.59 mg/g (96.5%) removal of hexavalent chromium from chromium-spiked waste water along with 99.6% removal efficiency of toxic dyes from textile industrial waste water within only 60 min of incubation time at pH 6. The PANI-NC nanocomposite showed high chromium removal capacity along with complete cleaning of industrial waste water and provides a potential to fabricate in a reusable, cost-effective system for waste water cleaning. [ABSTRACT FROM AUTHOR]