Fatima T. Esmadi

Sequential atomic absorption spectrometric determination of chloride and iodide in a flow system using an on-line preconcentration technique

A flow injection method is described for the sequential determination of chloride and iodide in a mixture of the two. The chloride–iodide mixture is precipitated from solution by silver nitrate and the precipitated silver chloride is dissolved by ammonia solution to determine chloride after which the precipitated silver iodide is dissolved by potassium cyanide solution to determine iodide. The method allows the analysis of about 15 samples h–1 and mixtures with different chloride : iodide ratios can be analysed at the µmol dm–3 level.

Indirect determination of chloride and carbonate by reversed flow-injection analysis coupled with atomic-absorption spectrometry and in-line preconcentration by precipitation.

Chloride and carbonate are determined indirectly by reversed flow-injection analysis with preconcentration by precipitation. The anions are precipitated in a Tygon tube containing glass beads and connected to an atomic-absorption spectrophotometer, and are then dissolved by suitable reagents. Chloride is precipitated as silver chloride, which is then dissolved with ammonia, sodium thiosulphate or potassium cyanide solution. Carbonate is precipitated as calcium carbonate, which is dissolved with hydrochloric acid. The response of the system has been optimized with respect to concentration, precipitation time, solution flow-rate and other AAS variables. Detection limits are 3 x 10(-7) and 5 x 10(-7)M for chloride and carbonate, respectively, with thiosulphate and hydrochloric acid as the dissolution agents.

Indirect Atomic Absorption Spectrometric Determination of Ammonia, Thiosulfate and Cyanide in an Unsegmented Flow System

Abstract A flow injection analysis method (FIA), has been developed for the determination of cyanide, thiosulfate and ammonia by atomic absorption spectrometry (AAS). Aqueous solution of the analyte was injected into an on-line column containing glass beads and packed with silver chloride and deionized water was used as the carrier. The analyte dissolves the silver chloride and the dissolved silver complex is introduced to the nebulizer of the AAS. This method has proved to be sensitive, simple and precise. Detection limits of 1.0 × 10−7 M, 5.0×10−7 M and 5.0x10−6M were obtained for thiosulfate, cyanide and ammonia, respectively. The precision of the technique was 2.0%, 2.4% and 1.4% in case of thiosulfate, cyanide and ammonia, respectively. The effects of flow rate and sample volume on the FIA/AAS signals are presented.

Organoruthenium chalcogen complexes: synthesis of tert-butyl-cyclopentadienyl dicarbonyl ruthenium thio- and seleno-carboxylate complexes and crystal structure determination of (tBuC5H4)Ru(CO)2SCO(3-NO2C6H4) and (tBuC5A4)Ru(CO)2SeCO(3,5-(NO2)2C6H3)

Abstract The substituted cyclopentadienyl organoruthenium dimers [( t BuC 5 H 4 )Ru(CO) 2 ] 2 (I) and [(1,3-Bu 2 -C 5 H 3 )Ru(CO) 2 ] 2 (II) were prepared from the reaction of Ru 3 (CO) 12 with t-butyl cyclopentadiene or 1,3-di-t-butylcyclopentadiene. The thermal reaction of dimer I with elemental sulfur or selenium afforded mixtures of organoruthenium polysulfides and polyselenides from which the binuclear pentasulfur and pentaselenium bridged complexes [( t BuC 5 H 4 )Ru(CO) 2 ] 2 (μ-S 5 )(III) and [( t BuC 5 H 4 )Ru(CO) 2 ] 2 (μ-Se 5 )(IV) were isolated and characterized. The organoruthenium sulfides and selenides readily react with acid chlorides RCOCI to give the S-bonded and the Se-bonded monothio- and monoseleno-carboxylate derivatives ( t BuC 5 H 4 )Ru(CO) 2 ECOR)(E  S, Se; R  3-NO 2 C 6 H 4 , 4-NO 2 C 6 H 4 , 3,5-(NO 2 ) 2 C 6 H 3 ). The crystal structures of [( t BuC 5 H 4 )Ru(CO) 2 SCO(3-NO 2 C 6 H 4 )] and [( t BuC 5 H 4 )Ru(CO) 2 SeCO(3,5-(NO 2 ) 2 C 6 H 3 )] were determined.

In vivo cytogenetic studies on rat’s bone-marrow cells of structurally related Schiff base complexes

The in vivo interactions of structurally-related Ni(II) and Fe(III) Schiff base complexes based on N-(8-quinolyl)salicylaldimine (HL1) and N-(8-quinolyl)napthaldimine (HL2) ligands with DNA molecules in the bone-marrow cells of rats were demonstrated using chromosomal aberrations (CAs) assay. The complexes differ by one aromatic group on the aldehyde site of the Schiff base (basicity or lipophilicity), or by the type of the central metal ions (Ni(II) or Fe(III)). Animals were injected intraperitoneally (i.p) with different concentrations of each drug, and CAs were examined in bone-marrow cells, 15 hours later. A significant increase in the frequency of CAs was induced upon treatment with 15 mg / kg weight of L1 complexes (P < 0.001), and not with L2 complexes (P > 0.05). Also, the magnitude of aberrations induced by L1-Ni(II) was higher than that induced by L1-Fe(III) (P < 0.01). The binding data, estimated using UV-Visible absorption technique, showed that the metal binding of HL1 was much greater than that of HL2 and that the affinity of HL1 towards Ni(II) is higher than that for Fe(III) ions. Thus, the trends in the presented in vivo results signify the important role of complex stability in predicting the clastogenicity of metal-ion-chelating Schiff base drugs.

Reverse flow injection analysis: Determination of trace amounts of metals using an on-line preconcentration technique

Determination of metal ion concentrations by reversed flow injection analysis using precipitation as a preconcentration technique is presented. The precipitate formed from the reaction of the cation and the anion, in a Tygon tube containing glass beads connected to the atomic absorption spectrophotometer, is dissolved by injection of a solution of a suitable dissolving reagent. The dissolving reagent dissolves the precipitate and the cation is transported to the atomic absorption spectrophotometer, yielding the signal. Three cations were tested to demonstrate the feasibility of the procedure: silver, calcium, and iron which were precipitated as silver chloride, calcium carbonate, and ferric hydroxide, respectively. Three dissolving reagents were investigated with silver chloride precipitate: ammonia, thiosulfate ion, and cyanide ion. Three other reagents were also used to dissolve ferric hydroxide precipitate: hydrochloric acid, phosphoric acid, and nitric acid. One reagent, hydrochloric acid, was used as a dissolving agent for calcium carbonate precipitate. Detection limits were 5 × 10−3, 4 × 10−2, and 8 × 10−4 ppm, respectively, for silver, iron, and calcium using thiosulfate, phosphoric acid, and hydrochloric acid as respective dissolving agents. The method could be applied easily to many routine analyses, such as water analysis due to its rapidity, precision, and small reagent consumption.

Organoruthenium sulfur complexes. Synthesis of (μ-S5) [RuCp(CO)2]2 and its reaction with acid chlorides. Preparation of RuCp(CO)2SCOR and molecular structure of RuCp(CO)2SCO(2-O2NC6H4)

Abstract The binuclear pentasulfur bridged organoruthenium complex, (μ-S 5 ) [RuCp(CO) 2 ] 2 (I), and other organoruthenium polysulfanes have been prepared by reaction of [RuCp(CO) 2 ] 2 with elemental sulfur upon refluxing or photolysis in benzene. These organoruthenium sulfanes readily react with acid chlorides, RCOCl, to give the S -bonded monothiocarboxylate derivatives, RuCp(CO) 2 SCOR (R = 1-C 10 H 7 (II), 2-FC 6 H 4 (III), 4-O 2 NC 6 H 4 (IV), 3,5-(O 2 N) 2 C 6 H 3 (V), 2-O 2 NC 6 H 4 (VI), C 6 H 4 COSFeCp(CO) 2 (VII)). The crystal structure of VI has been determined. Compound VI crystallizes in the monoclinic system, space group C 2/ c with a 1488.0(5), b 1359.4(3), c 1651.6(5) pm; β 115.68(2)°: Z = 8; R 1 = 0.027; R 2 = 0.027.

Atomic Absorption Spectrometric Determination of Silver, Bromide and Iodide Ions in a Flow System Using an on-Line Preconcentration Technique

Abstract Silver, bromide and iodide ions are determined using a flow analysis system and precipitation as a reconcentration technique. The precipitate formed by reaction of cation and anion in a Tygon tube containing glass beads and connected to the atomic absorption spectrophotometer is dissolved by passing a solution of suitable dissolving agent. The dissolving agent dissolves the precipitate and the formed soluble complex is transported to the atomic absorption spectrophotometer, yielding a signal. The signal height is proportional to silver concentration which is in turn proportional to anion concentration. Silver was precipitated as AgCl and dissolved by S2O3=, CN− and NH3 solutions, bromide was precipitated as AgBr and dissolved by S2O3=and CN− solution and iodide was precipitated as AgI and dissolved by CN− solution. This method has proved to be sensitive, simple and precise. The lowest detection limit is 4.6×10−9M for silver when it is precipitated as AgCl and dissolved by s2O3 2− solution, 1×10−6...

Genotoxicity of structurally related copper and zinc containing Schiff base complexes.

Abstract The utilization of Schiff bases in the industrial and pharmaceutical fields has led to an increase in their syntheses and evaluation of their biological activities. In this study, we described the synthesis and genotoxicity of two Schiff bases that share common platform in their construction, namely, naphthalene, and are complexed to either Cu(II) or Zn(II). The genotoxicity of these complexes was evaluated in cultured lymphocytes using sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs), and in rats using the urine 8-OH-2-deoxyguanosine (8-OH-dG) assay. The results showed that the examined complexes are genotoxic, but with different degrees. The order of genotoxicity of the complexes at 10 µg/mL was: Cu(L3)(NCS)(H2O) > Zn(L3)(NCS)(H2O) > Cu(L2)(NCS) > Zn(L2)(NCS), where L2 and L3 are the conjugate bases of N-(8-quinolyl)napthaldimine and N-(anilinyl)napthaldimine, respectively. However, at the 1-µg/mL concentration, only the Cu(L3)(NCS)(H2O) complex induced significant CAs, whereas at the 0.1-µg/mL concentration, only Cu(L3)(NCS)(H2O) and Zn(L2)(NCS) complexes induced significant SCEs, compared to controls. In the urine 8-OH-dG assay, all complexes at 10 mg/100 g body weight (b.w.) were found to cause DNA damage with the following order: Cu(L3)(NCS)(H2O) > Zn(L2)(NCS) > Zn(L3)(NCS)(H2O) > Cu(L2)(NCS), whereas no significant DNA damage was observed in animals exposed to 1 and 0.1 mg/100 g b.w. (p > 0.05). In conclusion, the two examined Schiff base complexes are found to induce DNA damage, but with different degrees.

Reaction of Some Schiff Base Complexes of Iron(III) with Nitrogen and Sulfur Donor Anions

Abstract Reactions of some Schiff bases with Fe(III) salts in the presence of nitrogen or sulfur donor anions have been investigated. The Schiff bases are derived from the reaction of salicylaldehyde, substituted salicyaldehyde or 2-hydroxy-1 -naphthaldehyde with 8-aminoquinoline, substituted aniline, ethylenediamine or o-phenylenediamine. The obtained Schiff bases act either as tridentate or tetradentate dibasic ligands. Tentative structures have been assigned on the basis of elemental analyses, conductivity, spectral and magnetic data. Most of the obtained complexes are proposed to be hexa-coordinate but some might be penta-coordinate. The added anions (thiocynate, 8-aminoquinolate, pyrrolidinedithiocarbamate or piperazinedi(dithiocarbamate) are bonded to iron, in addition to the Schiff base, producing mononuclear complexes or act as bridging groups producing dinuclear or polynuclear complexes.