Sensitive fluorescence detection of mercury(ii) in aqueous solution by the fluorescence quenching effect of MoS2 with DNA functionalized carbon dots.

A rapid and sensitive fluorescent sensor based on the MoS2 nanosheet/DNA/carbon dot nanoassembly has been developed towards the detection of mercury(ii) present in environmental samples. Bio-carbon dots (CDs) having strong fluorescence maxima at 451 nm were synthesized via one-step treatment with honey under low temperature carbonization. These CDs were nearly spherical with good size distribution and excellent monodispersity, and the average sizes of CD were around 2-4 nm as evidenced from transmission electron microscopy. The conjugation of DNA strands on the surface of the carbon dots provided an efficient fluorescent probe. The fluorescence of the MoS2 nanosheet/DNA/carbon dot nanoassembly enhanced gradually with the increase in the concentration of Hg2+ ions and the detection limit was found to be 1.02 nM. Furthermore, the fluorescence intensity was found to be linear with the concentration of Hg2+ ions in the range from 0 to 10 nM and their respective coefficient of determination was found to be 0.93676 and 0.98178. The present MoS2 nanosheet/DNA/carbon dot nanoassembly is highly selective toward Hg2+ ions over a wide range of metal ions tested.

Synthesis and characterization of 4-Halobenzylidene malanonitriles for optical detection of Nickel (II) ions in aqueous solution.

In this work, we have developed fluorescent detection techniques for the determination of Ni2+ ions in aqueous medium with sensitivity using metal coordinating fluorescent molecules namely 4-Halobenzylidene malanonitrile. The halogen substituted benzylidene malanonitile were synthesised Knoevenagel condensation reaction of various halogen substituted aromatic aldehydes with malanonitrile and products were characterised by IR and NMR spectroscopy. The obtained benzylidene malanonitiles and are exhibited a fluorescent emission with a peak of 430 nm, 440 nm and 448 nm for chloro, bromo and fluoro substituted compounds, respectively. The intensity of optical emission of the studied molecules is increased proportional to the addition of Ni2+ ions. The effect of different halogen substitution on the fluorescence behaviour of benylidene malononitrile has also been investigated. The synthesised title compounds showed a lowest detection limit of 10-20 M for the Nickel (II) ions in aqueous solution under UV-Vis absorption spectra. The molecule 4- Bromobenzylidene malanonitrile exhibited a lowest detection limit of 10-19 M for the Nickel (II) ions in, aqueous solution, photoluminescence analysis.

PbS/graphene hybrid nanostructures coated glassy carbon electrode for the electrochemical sensing of copper ions in aqueous solution.

In this research, we have studied the electrochemical sensing of Cu(II) ions in aqueous solution using PbS/Graphene composite nanostructure coated glassy carbon electrode (GCE). The SEM-EDAX analysis revealed that the lead sulphide nanocrystals are homogeneously embedded on the graphene nanosheets with an uniform particle size of 100 nm, and the elements presents 92.32% and Lead content of 5.45% and Sulfur content of 0.91%. Raman spectra exhibits G with respect to the E2g sp2 hybridized C-C and D band with respect to the A1g mode in the disordered edge region of the GNS. The composite nanostructure coated GCE (PbS/Graphene/GCE) was prepared and its performance in the existence of metal ions such us Cd(II),Pb(II), Mg(II), Cu(II) and Ni(II) was studied using the current voltage curves in double distilled water within the scan rates of 25 to 300mVs-1. The PbS/Graphene coated carbon electrode exhibited the higher anodic and cathodic peak current for copper solution than the other metal ions studied, which various linearly proportional to concentration. The electrochemical sensing characteristics PbS/GNS/GCE was found to be significant towards detecting Cu2+ ion within the concentration range of 1 × 10-4 to 1 × 10-8 M, with a lowest sensing detection limit of 1 × 10-8 M.

Erythrocyte morphology under phase contrast microscopy in haematuria.

Fresh urine samples from twenty patients with macroscopic haematuria were examined by phase contrast microscopy to study the erythrocyte morphology. Other appropriate investigation like - renal biopsy in suspected glomerulonephritis and appropriate urological investigations in other cases to prove the site of origin of erythrocyte were done in all cases. Changes in erythrocyte morphology were observed in all the 12 patients with histological evidence of proliferative glomerulonephritis. These changes included extrusion of cell cytoplasm (39.5%), 'Doughnut' cell (26.5%) budding cell (15%) and cell membrane rupture with loss of cytoplasm (15%). Overall 83.3% of the erythrocytes showed some morphologic change or the other. In 8 patients where bleeding was into the pelvicalyceal system, ureter or bladder, 95% of RBCs showed no discernible morphologic change. It is concluded that the morphological changes in the erythrocyte identified under the phase contrast microscope can help to differentiate between glomerular and non glomerular causes of bleeding.