Faculty of Applied Sciences
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Item Analysis of lubricating grease by ICP-OES : a case study on preparation methodology(Asian Publication Corporation, 2016-01-30) Marume, Cathrine; Kumar, Bhajanthri Natesh; Redhi, Gan G.The aim of this study was to develop simple, cost effective and reliable sample preparation methods for the analysis of lubricating grease samples. Direct dilution, microwave digestion and emulsification methods were designed and compared for the analysis of Ca, B, Al, Na, Mo, Zn and Ba with inductively coupled plasma optical emission spectroscopy (ICP-OES). The direct dilution method gave most inconsistent results in terms of percentage recovery. The optimized microwave digestion and emulsification methods compared well and showed good reliability in terms of sensitivity and selectivity. The calibration curves resulting from oil emulsion has no significant difference with that of aqueous emulsions, but the stability of the emulsified samples was very low. The limit of detection and limit of quantification values obtained from the microwave digestion method were very low and therefore it is superior amongst the three methods for the analysis of various lubricating grease samples.Item Spectrophotometric determination of Cadmium(II) in water and soil samples using Schiff's bases(Asian Publication Corporation, 2016) Kumar, Bhajanthri Natesh; Kumar, S. Himagirish; Redhi, Gan G.A simple and rapid method was developed with the two novel Schiff ’s base ligands, (E)-N'-(2-hydroxy-5-nitrobenzylidene)isonicotinoylhydrazone and 2-(4-fluoro benzlideneamino)benzenothiol for monitoring the cadmium(II) in different water and soil samples. The two ligands react with cadmium(II) at pH 4.9/5.7 to form pale yellow/pale brown complexes with stoichiometric ratios of 1:1 (M:L). The complexes obeyed Beer’s law in the range of 2.0 and 2.5 mg L-1 with an excellent linearity in terms of the correlation coefficient of 0.99. The molar absorptivity and Sandell’s sensitivity of the complex systems were found to be 3.68 × 104, 4.32 × 104 L mol-1 cm-1 and 0.00298, 0.0034 μg cm-2, respectively. The limit of detection for cadmium(II) was noted as 0.042 and 0.063 μg L-1, respectively for these ligands. Furthermore, in vitro antimicrobial activities of both ligands and their complexes were successfully examined and reported.Item Ionic liquid based high performance electrochemical sensor for ascorbic acid in various foods and pharmaceuticals(Elsevier, 2016-07-18) Kumar, Bhajanthri Natesh; Arumugam, Vasanthakumar; Chokkareddy, R.; Redhi, Gan G.In the present study, 1-butyl-3-methyl imidazolium tetra fluoroborate ionic liquid (IL), boron nitride (BN) and magnetite nanoparticles (Fe3O4NPs) based nanocomposite (IL-BN-Fe3O4NPs) was successfully synthesised and used to fabricate glassy carbon electrode (GCE) for the determination of ascorbic acid (AA). The nanocomposite was characterized by Fourier transformation infrared spectroscopy (FTIR), x-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS) and transmission electron micros-copy (TEM) techniques to observe the surface morphology. Cyclic voltammetry (CV) was performed to assess the electrochemical performance of IL-BN-Fe3O4NPs/GCE towards ascorbic acid (AA) in 0.1 M phosphate buffer solu-tion (PBS) at pH 7. The CV results obtained reveal that the significant enhancement of anodic peak current with increased sensitivity and conductivity. The differential pulse voltammetric results obtained indicates the linear increment of electrochemical signals with an increase in the concentration of AA in the range of 1–12 μM. Based on the calibration plot, limit of detection and limit of quantification were calculated and found to be 0.042 and 0.139 μM respectively. The electrochemical sensor showed outstanding sensitivity, selectivity, repeat-ability and stability. In addition to this IL-BN-Fe3O4NPs/GCE sensor was practically applied for the routine analysis of AA in various food and pharmaceutical samples.