http://nopr.niscpr.res.in/handle/123456789/20485 2026-10-12T22:03:34Z http://nopr.niscpr.res.in/handle/123456789/20508 Title: Improved selectivity to orthophosphate, pyrophosphate and triphosphate by adding metal ions to a tripodal ligand Authors: Guo, Yan-He; Ge, Qing-Chun; Lin, Hai; Lin, Hua-Kuan; Zhu, Shou-Rong; Zhou, Chang-Yue Abstract: The strong and selective binding of phosphate (PO), pyrophosphate (PP) and triphosphate (tP) by tripodal ligand N, N, N-tri((2-aminoethyl)thioethyl)-amine (L) has been studied in aqueous solution at <i>I </i>= 0.1 mol dm^-3 KNO₃ and 25°C. The interactions between L and the inorganic substrates are described and equilibrium constants for each species formed have been determined. The stability constants of 1 : 1: 1 M (M = Cu²⁺ or Zn²⁺):L:S (S = PO, PP, tP) are determined by potentiometric <i>p</i>H titrations. The interactions of Zn(II)/L/phosphate systems and Cu(II)/L/phosphate systems are investigated by ³¹P NMR and EPR spectra respectively. The results show that metal ion acts as "messenger" or bridge between the receptor and the substrate, and the existence of metal ion in the ternary systems leads to competition between the mixed ligands. The metal ion improves the selectivity and recog nition of the substrates by protonated tripodal ligand. Page(s): 116-120 2003-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/20507 Title: Analytical properties of 2-acetylthiophene-4- phenyl-3-thiosemicarbazone: Spectrophotometric determination of copper(II) in edible oils and seeds Authors: Prasad, B L; Reddy, K Hussain; Reddy, T Sreenivasulu Abstract: The analytical properties of 2-acetylthiophene-4-phenyl-3-thiosemicarbazone (ATPT) are described for the first time. The reagent gives yellowish green coloured complex with copper(II) in sodium acetate - acetic acid buffer (<i>p</i>H 3.0-6.0) medium. This colour reaction (molar absorptivity, 2.92 × 10⁴ L mol^-1 cm^-1 at 385nm) has been investigated for the spectrophotometric determination of copper in edible oils and seeds. Page(s): 112-115 2003-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/20506 Title: Direct and derivative spectrophotometric determination of zirconium(IV) with 2,4-dihydroxy benzaldehyde isonicotinoyl hydrazone Authors: Sivaramaiah, S; Reddy, P Raveendra; Reddy, V Krishna; Reddy, T Sreenivasulu Abstract: A simple and sensitive spectrophotometric method has been developed for the determination of zirconium(IV) in aqueous medium. The metal ion forms golden yellow coloured, soluble complex with 2,4-dihydroxy benzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) at <i>p</i>H<i> </i>1.5 with λ_max at 410 nm. Beer's law is obeyed in the range 0.40-4.00 μg ml^-1 of Zr(IV). The molar absorptivity and the Sandell's sensitivity of the method are 1.82×10⁴ lit mol^-l cm^-1 and 0.005 μg cm^-2, respectively. The interference of various ions has been studied. The complex has a 1:2 [Zr(IV):2,4-DHBINH] stoichiometry. A method for the determination of zirconium(IV) by first order derivative spectrophotometry has also been proposed. Page(s): 109-111 2003-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/20505 Title: Corrosion behaviour of carbon steel in DTPMP inhibited neutral medium Authors: Rai, Vandana; Pitre, Krishna S Abstract: Corrosion rate for mild steel in neutral medium (model water) has been studied using a new voltammetric procedure. The synergistic effect of Zn⁺⁺ion with DTPMP inhibitor has revealed favourable results. Corrosion rate has been determined as a function of time, using gravimetric and electrochemical methods. The corrosion inhibition efficiency of DTPMP+Zn is fund to be 80% after 24 h. Page(s): 106-108 2003-01-01T00:00:00Z