A green synthesis of polyvinylpyrrolidone stabilized platinum nanoparticles (PtNPs) has been done by microwave irradiation in the presence of glucose. The formation process of the PtNPs is pursued by UV-visible spectroscopy. The morphology of the PtNPs was characterized by transmission electron microscopy and X-ray diffraction techniques. Catalytic activity of the above PtNPs has been substantiated through photodecolorization of aqueous methyl violet solution.

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Flow diagram of the procedures for the analysis of surfactants using modified GFF paper substrate.

The removal of phenolic compounds, i.e., o-cresol, m-cresol, and p-cresol from aqueous solution have been evaluated employing activated carbon (AC) coated with polymer supported iron nanoparticles (FeNPs). The synthesized FeNPs were characterized by scanning electron microscope and X-ray diffraction analysis. High correlation coefficient values indicated that the adsorption of phenolic compounds onto AC coated with polyvinylpyrrolidon (PVP) supported FeNPs obey Freundlich and Langmuir adsorption isotherms. Higher Freundlich and Langmuir constant values for AC coated with PVP supported FeNPs indicated its greater efficiency than AC. The adsorption data are well represented by both the Freundlich and Langmuir isotherms, indicating favourable adsorption of cresols by the adsorbents. Cresols were effectively removed (90 %) by adsorption process from aqueous solution using AC coated with FeNPs. The percentage removal of above phenolic compounds was studied under varying experimental conditions such as pH, temperature, adsorbent dosage, and contact time. The adsorption of phenolic compounds is quite sensitive to pH of the suspension and optimum uptake value was found at pH 7.0. Temperature also has a favorable effect on adsorption when varied from 20 to 50°C. On the contrary, beyond 30°C, a decrease in the adsorption was noticed.

26A novel hyphenated single-drop micro-extraction (SDME) diffuse-reflectance Fourier-transform infrared 27 spectroscopy (DRS-FTIR) were employed for quantification of hexavalent molybdenum, i.e., Mo(VI) in human 28 blood serum and urine. Mo(VI) was extracted as Mo (VI):HDPBA complex in single-drop of dichloroethane 29 solution of N 1 -hydroxy-N 1 ,N 2 -diphenylbenzamidine (HDPBA). Mo(VI) formed 1:2 complex in organic phase 30 with HDPBA in acidic medium, which was further analyzed by diffuse-reflectance Fourier-transform infrared 31 spectroscopy (DRS-FTIR). The factors affecting for SDME process, such as extraction solvent, size of the 32 acceptor drop volume, pH, reagent concentration, extraction time and stirring rate were optimized for better 33 extraction efficiency. The extracted micro-drop was analyzed using DRS-FTIR, the most steady and the 34 strongest vibrational IR peak at 911±2 cm -1 (υ 1 ) corresponding to asymmetric stretching mode of MoO 4 2was 35 selected for quantification of Mo(VI). The limit of detection (LOD) and limit of quantification (LOQ) for method 36 were 8.0 ng mL -1 and 26.4 ng mL -1 , respectively. The absorbance and peak area were determined by 37 SDME/DRS-FTIR method, which showed excellent linearity with correlation coefficient value of 0.99 for the 38 concentration range of 1-100 ng mL -1 . The standard deviation (SD) and relative standard deviation (RSD) for 39 10 replicate measurements were found to be 0.13 ng mL -1 and 1.3%, respectively, at a level of 10 ng mL -1 40 Mo(VI) in aqueous phase. 41 42 43 44 Key words: Single-drop micro-extraction, HDPBA, Mo(VI) determination, quantitative IR peak, DRS-FTIR, blood 45 serum and urine 46 47 48 49