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[Display omitted] • The methodology is demonstated with the help of two simple benzothiazole based organic probe molecules (R and P). • The sensing of aqueous fluoride ion is acheived with both the probe molecules in presence of Ni(II) and Cu(II) salt. • The mechanism behind the claimed observation is duly studied with the help of 1H NMR, UV–Vis spectroscopy, EPR spectroscopy, cyclic Voltammetry and theoretical caculation. • The sensing of fluoride ion in aqueous medium is finally demonstrated with the help of UV–Vis spectroscopy and Differential Pulse Voltammetry (DPV) technique. • The methodlogy is finally validated by measuring the fluoride ion concentration in the water sample collected from the fluoride affected areas of Assam, India. Excess consumption of fluoride through drinking water causes detrimental effects to human health which has been a serious global concern. This situation demands routine monitoring of fluoride in drinking water in fluoride affected regions around the world. A plethora of organic molecules has been demonstrated as chemosensors based on the fluoride induced deprotonation reaction of the probe molecules. However, most of the probe molecules fail to react with fluoride in aqueous medium which limits their application. Herein, we have demonstrated a metal ion, Ni(II) mediated strategy to retain the reactivity and the sensitivity of the probe molecule towards fluoride ion in aqueous medium with the help of two benzothiazole based probe molecules (R and P). Both the probe molecules showed retention of the affinity towards fluoride ion in aqueous medium in presence of Cu2+ ion but the colorimetric response is not upto the mark. On the other hand, the probe molecule P showed excellent affinity and colorimetric response towards aqueous fluoride ion in presence of Ni2+ ion. The methodology is validated with UV–Vis spectroscopy and Differential pulse voltammetry (DPV) technique. Probe molecule P in presence of Ni2+ ion showed limit of detection values 0.60 ppm and 0.57 ppm w.r.t. UV–Visible spectroscopy and DPV technique respectively. Furthermore, the efficiency of the methodology w.r.t. P was tested with real samples collected from the fluoride affected areas of Assam, India and found that the data corroborates well with the results of ion selective electrode. This methodology can provide a new dimension in the development of a low cost method for routine sensing of fluoride ion with organic probe molecules in drinking water for low resource world. [ABSTRACT FROM AUTHOR]

Gardenia latifolia Ait. (Rubiaceae) is also known as Indian Boxwood is a small deciduous tree often growing in southern states of India. In the present study, phytochemical profiling of methanolic extract of G. latifolia fruits were carried out using FTIR and LC-MS/MS analysis. Besides, its antioxidant and antimicrobial potential have been analysed using DPPH activity, differential pulse voltammetry and resazurin microtiter assay, respectively. Phytochemical profiling revealed the presence of 22 major diversified compounds and main were 3-caffeoyl quinic acid (chlorogenic acid), 3,4-Di-O-caffeoyl quinic acid, 6-O-trans-feruloylgenipin gentiobioside, 10-(6-O-trans sinapoyl glucopyranosyl) gardendiol, isoquercitrin, scortechinones, secaubryenol, iridoids and quercetin 3-rutinoside (rutin). The extract showed antioxidant activity (IC50 = 65.82) and powerful antibacterial activity with lowest minimum inhibitory concentration against Gram-positive Staphylococcus aureus (15.62 µg/µL), Bacillus subtilis (31.25 µg/µL) than gram negative Escherichia coli (62.5 µg/µL), Klebsiella pneumoniae (62.5 µg/µL), Pseudomonas aeruginosa (31.25 µg/µL). This study shows that the fruits of G. latifolia have tremendous potential to be used in food industries, phyto-therapeutics and cosmetic industries. [ABSTRACT FROM AUTHOR]

Herein, for the first time, any phytochemical-based silver nanoparticle is reported as a dual sensor to detect toxic dithiocarbamate fungicide (Thiram) spectrophotometrically and electrochemically. Green approach was employed for the silver nanoparticle synthesis utilizing the stem extract of Coscinium fenestratum via a microwave-assisted route. The characterization of silver nanoparticles was carried out by methods such as UV–visible, Fourier transform-infrared, and X-ray diffraction spectroscopy, as well as transmission electron microscopy techniques. The diffraction and microscopic studies proved that the nanoparticles were essentially crystalline and almost spherically shaped with average size of 20.72 ± 4.25 nm. The nanoparticles were found very stable for more than 6 months and hence are appropriate for remediation of several issues regarding environment such as detection of fungicide as well as organic dye degradation. Thus, the nanoparticles were explored for selective recognition of Thiram and obtained a low limit of detection of 0.18 ppm, much lower than 7 ppm, the maximal residue limit as per the environmental protection agency of the USA. Moreover, the nanoparticles successfully detected Thiram from real samples from tap, canal, and river water in the state of Kerala, India. Furthermore, the nanoparticles were utilized for their excellent catalytic efficiency toward the swift degradation of three water contaminant organic dyes, namely methylene blue, methyl orange, and naphthol green B within a couple of minutes. [ABSTRACT FROM AUTHOR]

• Ce-CNFs are synthesized using CVD technique. • The average diameter of synthesized Ce-CNFs ranges from 20 nm to 40 nm. • The linear range and LOD of Cu (II) ions are 0.6–1.8 ppb and 0.3 ppb respectively. • The linear range and LOD of Pb (II) ions are 0.9–2.1 ppb and 0.6 ppb respectively. Chemical vapor deposition (CVD) grown cerium oxide catalyzed 1-D carbon nanofibers (Ce-CNFs) were synthesized first time via tip growth mechanism for the sensitive, selective and simultaneous determination of heavy metals/ions, i.e., Pb (II) and Cu (II). Acetylene and cerium oxide was used for growing the Ce-CNFs via CVD process as carbon source and catalyst for decomposing the acetylene respectively. Inexpensive polymethyl vinyl ether-alt-maleic anhydride (PMMVEA) was used as a binder rather than expensive Nafion solution. Ce-CNFs modified glassy carbon electrode was used as working electrode in three electrode assembly for simultaneous selective detection of Pb (II) and Cu (II) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The fabricated Ce-CNF electrode exhibited a linear behavior with Pb (II) and Cu (II), and the limit of detection was found to be 0.6 ppb and 0.3 ppb respectively. The electrode material was efficaciously tested against real water sample (Gomti river, Lucknow, India), for checking its practical applications. The prepared Ce-CNFs modified electrode is relatively nontoxic and low-cost. Consequently, it could be directly employed as a real-time electrochemical sensor for simultaneous determination of Pb (II) and Cu (II) ions. [ABSTRACT FROM AUTHOR]

The importance of study of heavy metal distribution in river sediments is a component in understanding the exogenic cycling as well as in assessing the effect of anthropogenic influences of the elements. In India, the river Subernarekha flows over Precambrian terrain of Singhbhum craton in the eastern India. The geological succession in this part of India is through (1) iron ore series, (2) ultrabasic igneous rocks, (3) diorite, (4) granite, (5) newer dolerites, (6) newer tertiary and (7) alluvium. The first four groups belong to the Archaean era, and the representative is the iron ore series consisting of iron ore, manganese and chromite which are abundantly present. The primary rock types are schist and quartzite layers. One main tributary, the Kharkhai flow through granite and schist and quartzite layers. Two important creeks are Gurma and Garra, respectively. The former after originating in basic igneous area travels through schist quartzite, while the later one originates in granite area where some functional but old gold mines are located. Freshly deposited sediments of river were collected upstream and downstream the industrial zone (East Singhbhum district). Samples were collected from four locations and analysed in <63 μm sediment fraction for heavy metals like Ni, Co and Cr by adsorption stripping voltammetry on hanging mercury drop electrode and Hg by anodic stripping voltammetry using polished rotating gold disk electrode. Enrichment of these metals over and above the local natural concentration level (NCL) has been calculated and applied to determine metal-pollution index (MPI) proposed by Goncalves et al. and also geo-accumulation index ( I geo) by Muller. Based on Muller’s classification, Ni, Cr and Hg have been classified from unpolluted to moderately polluted range in pre-monsoon period but for metals Ni and Cr, during the post-monsoon period the values have reached moderately polluted level while Hg has been classified under unpolluted to moderately polluted level except at the monitoring station situated upstream to Gurma Creek where it was found at unpolluted level. Presence of natural resources of the minerals is primarily the reason for their detection in river sediments (lithogenic) but some anthropogenic sources are also contributing for their presence at some sampling stations. Hg is considered to be chalcophilic in nature and is detected wherever known sulphidic ores of copper or nickel are present. [ABSTRACT FROM AUTHOR]

The trace element contents of five varieties of instant coffee powder available in the Indian market have been analysed. Ca, Cr, Fe, K, Mg, Mn, Ni, Sr, Zn and Pb, Cd, Cu have been determined using atomic absorption spectrophotometry and differential pulse anodic stripping voltammetry, respectively. The metal levels in the coffee powders observed in this study are comparable with those reported for green coffee beans (Arabica and Robusta variety) reported worldwide with the exception of Sr and Zn, which were on the lower side of the reported values. Concentrations of these metals have been converted into intake figures based on coffee consumption. The daily intakes of the above metals through ingestion of coffee are 1.4mg, 1.58 mu g, 124 mu g, 41.5mg, 4.9mg, 17.9 mu g, 2.9 mu g, 3.8 mu g, 12.5 mu g, 0.2 mu g, 0.03 mu g and 15.5 mu g, respectively. The values, which were compared with the total dietary intake of metals through ingestion by the Mumbai population, indicate that the contribution from coffee is less than or around 1% for most of the elements except for Cr and Ni which are around 3% . [ABSTRACT FROM AUTHOR]