1,720,974 research outputs found
High-performance liquid chromatographic determination of Mn(II), Co(II), Zn(II), Ni(II), Cu(II) as coproporphyrin-I complexes
No full textThe mobilities of 3,8,13,18-tetrametyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) and five metal-CPI complexes were measured by reversed-phase high performance liquid chromatography (RP-HPLC) on a octadecyl-bonded silica gel (C18 silica) with developing solvent (69:31 v/v) methanol-buffer at pH 7 (buffer ionic strength 0.270 mol L−1. 0.018 mol L−1 boric, phosphoric and acetic acid, and 0.036 mol L−1 sodium hydroxide), and 0.050 mol L−1 of NaCl, with UV detection at 374 and 458 nm
Kinetic and equilibrium studies on mercury(II)-coproporphyrin-I. Metal ion exchange reaction with cobalt(II) and application to determination of trace mercury(II)
No full textThe reaction of 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) with mercury(II) was studied spectrophotometrically, and kinetic and equilibrium constants were determined; the influence of temperature on the reaction rate was also studied. It was verified that mercury(II) accelerates the incorporation reaction of cobalt(II) into CPI; the kinetics and mechanism of this reaction at high alkaline pH were studied. Sensitive kinetic methods for the determination of mercury(II) at ppb levels have been established; the apparent molar absorbivity and Sandell's sensitivity for the recommended procedure, at 368 nm, and 400 s after the start of the reaction, were: 4.23×105 (l mol−1cm−1) and 0.474 (ng cm−2) (for A=0.001)
Determination of stability constants of Cu(II), Co(II), Zn(II), Ni(II) and Mn(II) chelates with 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid by reversed-phase high performance liquid chromatography
No full textThe stability constants (KML) of Cu(II), Co(II), Zn(II), Ni(II), and Mn(II) chelates with 3, 8, 13, 18 -tetrametyl-21H, 23H-porphine -2,7,12,17- tetrapropionic acid, or coproporphyrin-I (CPI) have been determined by reversed-phase high performance liquid chromatography (RP-HPLC) on a octadecyl-bonded silica gel (C18 silica) with developing solvent (69:31 v/v) methanol-buffer at pH 7 (buffer ionic strength 0.270 mol L−1: 0.018 mol L−1 boric, phosphoric and acetic acid, and 0.036 mol L−1 sodium hydroxide), and 0.050 mol L−1 of NaCl, with UV detection.
The values of log KML were 6.02±0.26 for the Cu(II), 5.37±0.18 for the Co(II), 4.51± 0.21 for the Zn(II), 4.52± 0.21 for the Ni(II) and 6.38± 0.04 for the Mn(II)
Reactions of metal-ions with 3,8,13,18-tetramethyl-21H, 23H-porphine-2,7,12,17-tetrapropionic acid: mechanisms, kinetics and analytical applications
No full textReactions of metal-ions with 3,8,13,18-tetramethyl-21H, 23H-porphine-2,7,12,17-tetrapropionic acid: mechanisms, kinetics and analytical application
Kinetics of the metallation of coproporphyrin-I in water with cadmium(II) and manganese(II)
No full textThe reaction of 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or
coproporphyrin-I (CPI) with cadmium(II) was studied spectrophotometrically and its kinetic and equilibrium
constants were determined. The influence of temperature on the reaction rate was also studied. At different
ratios of [CPI][Cd(II)] two types of complex were formed: CdII(CPI) and (CdII)2(CPI); an investigation of the
solution properties and the mechanism of aggregation of (CdII)2(CPI) at different pH were performed. It is
verified that cadmium(II) accelerates the reaction of the incorporation of manganese(II) into CPI by the
substitution of cadmium(II) with manganese(II) in the CdII(CPI) complex; the kinetics and mechanism of this
substitution reaction at alkaline pH were studied. A sensitive kinetic method for the determination of
cadmium(II) at ppb levels has been established; the molar absorptivity and the Sandell’s sensitivity (for
A = 0.001) of the recommended procedure at 458 nm and 300 s after the start of the reaction are
(6.175 0.026) 105 1 mol-1 cm-1 and (1.820 0.008) 10-4 mg cm-2 respectively
Complessi del rame(II) e del cobalto(II) con coproporfirina-1 e loro caratterizzazione spettrofotometrica
No full textDeterminazione di Mn(II), Co(II), Ni(II), Cu(II) e Zn(II) mediante complessamento con Coproporfirina-1 e separazione con RP HPLC.
No full textStudy of solvent extraction of mercury(II) with dibenzo-18-crown-6 from hydrochloric acid solution into benzene
No full textThe effect of Li+, K+, NH+4, Ca2+ or Sr2+ in the extraction of mercury(II) as chloro-complexes from solutions in hydrochloric acid with dibenzo-18-crown-6 (DB18C6) into benzene and the stoichiometries of the reactions have been studied. The crystalline extracted species were characterized by morphological and microanalysis measurements by scanning electron microscopy and energy dispersive X-ray spectrometry respectively
Kinetic evidence for the mechanism of the metal-substitution reaction of lead(II)-porphyrin with cobalt(II)
No full textThe catalytic effect of lead(II) in the reaction of 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid with cobalt(II) has been studied and the kinetic evidence is reported
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