Indian Journal of Chemistry

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical


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VOLUME 45A

NUMBER 5

May 2006

CONTENTS

Papers

 

1099

 

Is electrophilicity a kinetic or a thermodynamic concept?

 

 

 

 

 

 

 

P K Chattaraj*, U Sarkar, D R Roy, M Elango,
R Parthasarathi & V Subramanian*

 

 

 

Friedel-Crafts benzylation, acetylation and benzoylation reactions, electrophilic addition to various substituted ethylenes and electrophilic aromatic substitution reactions in toluene and chlorobenzene have been studied to analyse whether the electrophilicity index is a reliable descriptor of the kinetic behaviour or not. It has been observed that if a few systems are neglected the electrophilicity correlates very well with the experimental rates and hence is essentially a kinetic concept, which has also inherited an adequate amount of thermodynamic information due to inter-correlations.

 

 

1113

 

Inclusion complex of 1,2,3-trihydroxybenzene with a- and b-cyclodextrin

 

 

 

 

 

 

 

T Stalin, P Vasantha Rani, B Shanthi, A Sekar &
N Rajendiran*

 

 

 

Effect of a-cyclodextrin (a-CD) and b-cyclodextrin (b-CD) on the absorption and fluorescence spectra of pyrogallol is discussed. The thermodynamic parameters values indicate that the inclusion processes are exothermic and spontaneous. b-CD studies reveal that pyrogallol forms 1:1 inclusion complex with
b-CD. The small formation constant of THB shows that this molecule is not tightly embedded in the b-CD cavity. Of the two CDs, b-CD can more readily include pyrogallol than a-CD.

 

 

1121

 

Manganese(II) complexes having pseudohalide coordination: Synthesis, IR spectroscopy and X-ray crystal structures of [Mn(L1)(NCS)2] and [Mn(L2)(NCS)2] compounds involving Schiff bases

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tapan K Karmakar, Barindra K Ghosh &
Swapan K Chandra*

 

 

 

The synthesis and crystallographic characterization of two new mononuclear manganese(II) complexes with thiocyanate coordination [Mn(L1)(NCS)2] and [Mn(L2)(NCS)2] (L1 and L2 = tetradentate ligand, derived from bis condensation between pyridine-2-carboxaldehyde and 1,3-diaminopropane, and
2-benzoyl pyridine and 1,3-diaminopropane respectively) are described.

 

 

1126

 

Synthesis, characterization, spectroscopic and electrochemical studies of new thioether ligated octahedral low-spin cobalt(II) complex: Oxidative cleavage of C-S bond

 

 

 

 

 

 

 

 

 

 

Chandrama Basu, Santanu Chowdhury &
Soma Mukherjee
*

 

 

 

A rare thioether ligated octahedral low-spin bivalent cobalt complex [CoII(PhL)], (d7, t2g6e1, S = 1/2, meff = 1.88 mB), has been obtained by reaction of cobalt(II) acetate tetrahydrate with dithiaalkyl substituted  aryl azo-oxime ligand HON=C(Ph)N=NC6H4S(CH2)2 SC6H4N=NC(Ph)=NOH, H2PhL. Interestingly, the dithiaalkyl motif in [CoII(PhL)] undergoes an oxidative cleavage of C-S bond.

 

 

 

1131

 

Alkylation of phenol with tert-butyl alcohol catalysed by some sulphated titania systems

 

 

 

 

 

 

 

 

 

 

 

K R Sunajadevi & S Sugunan*

 

 

 


 

 

1139

 

Synthesis, characterization and thermal behaviour of ZnS4P2 chromophore as prototype

 

 

 

 

 

 

 

Shahab A A Nami, K S Siddiqi* & Yonas Chebude

 

 

 

Complexes of the type M(PPh3)2(dtc)2 where M = Co(II), Ni(II), Zn(II) and Hg(II), PPh3 = triphenylphosphine and dtc = sodium diethyldithiocarbamate, have been synthesized and characterized by elemental analysis, IR, UV-vis spectroscopy, TGA/DSC, magnetic moment and conductivity measurements.

 

 

1144

 

Electrochemical oxidation of ethanol on thin coating of platinum based material on nickel support

 

 

 

 

 

 

 

 

 

 

 

Pradip Paul, Joyeeta Bagchi &
Swapan Kumar Bhattacharya*

 

 

 

Electrochemical oxidation of ethanol has been studied on thin deposits of platinum and co-deposits of platinum and ruthenium on Ni- support from different baths. Polarization and chronopotentiometric studies indicate the intrinsic superiority of Ni/Pt-Ru electrodes over Ni/Pt and Ni electrodes. The overall electrocatalytic activity of the coated electrodes follows the order: Ni/Pt(PVA) > Ni/Pt > Ni/Pt-Ru(PVA) > Ni/Pt-Ru > Ni, (where PVA is polyvinyl alcohol). Steady state polarization, cyclic voltammetry, chronopotentiometry and SEM images have been used to correlate the catalytic activity of such electrodes with the characteristics of the deposits and surface morphology.

 

Notes

 

1153

 

Synthesis and spectral characterization of palladium(II) and silver(I) complexes of antipyrine-azo-imidazoles

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S Senapati, Sk. Jasimuddin & C Sinha*

 

 

 

 

Two groups of Pd(II) and Ag(I) complexes of antipyrine-azo-imidazoles, viz., Pd(2)Cl2 and [Ag(2)2](ClO4), have been synthesized and characterized.

 

 

 

 

 

1158

 

Kinetics and mechanism of the oxidation of organic sulphides by quinolinium bromochromate

 

 

 

 

 

 

 

 

 

Varsha Dhariwal, Deeksha Yajurvedi &
Pradeep K Sharma*

 

 

 

The oxidation of sulphides by quinolinium bromochromate (QBC) results in the formation of the corresponding sulphoxides. The reaction is first order with respect to both QBC and the sulphide and is catalysed by hydrogen ions. The rates of the ortho-compounds show excellent correlation with the LDRS equation. The oxidation of alkyl phenyl sulphides is subject to both polar and steric effects of the alkyl groups. The polar reaction constants are negative indicating an electron-deficient sulphur centre in the slow step. A mechanism involving formation of a sulfurane intermediate in the slow step has also been proposed.

 

 

1165

 

Effect of DMF on the solvation behaviour of BiCl3 in CH3OH and CH3CN: A conductometric study

 

 

 

 

 

 

 

J Ishwara Bhat* & T N Sreelatha

 

 

 

The effect of addition of dimethyl formamide on the conductivity and solvation behaviour of BiCl3 in CH3OH and CH3CN at four different temperatures is reported. In both the solvents, the conductivity is found to decrease and the solvation is found to increase on addition of DMF at all temperatures.

 

 

1170

 

Effect of side arm chain length of redox ionophores on uptake of some metal ions

 

 

 

 

 

Anubhuti Awasthy, Mamta Bhatnagar,
Nidhi Joshi & Uma Sharma*

 

 

 

The redox switched ionophores 1-[1-anthraquinonyloxy] 3, 6 dioxaoctane-8-methane (A1) and 1-[1- anthraquinonyloxy] 3 oxapentane-5-methane (A2) have been synthesized and used as carriers in liquid membrane transport and extraction studies of alkali and alkaline earth metal ions. The sequence of metal ions extracted and transported by ionophore A1 is: Ca2+>K+>Li+>Mg2+and Li+>K+>Ca2+>Mg2+ respectively; and by the ionophore A2 is Li+>K+>Ca2+ and Ca2+>K+>Li+ respectively. Ionophore A1 is selective for Ca2+ while ionophore A2 is selective for Li+ ions. This selectivity may be used in ion selective electrodes and redox switchable devices.

 

 

1173

 

Voltammetric determination of dna based on its interaction with neutral red

 

 

 

 

 

 

Wei Sun*, Jiayu You, Qingxiang Wang & Kui Jiao

 

 

 

A new linear sweep voltammetric assay of fsDNA based on its interaction with neutral red is presented. At pH 8.0, the dye can bind with DNA to form a supramolecular complex, which results in the decrease of the linear sweep voltammetric reductive peak current at
–0.60 V (vs. SCE) on the mercury electrode. Under optimal conditions, there is little interference from most metal ions and amino acids. The calibration graph for fsDNA is linear in the range of 1.0~30.0 mg/L with the detection limit as 0.67 mg/L.

 

 

1178

 

Spectrophotometric determination of arsenic via nanogold formation in micellar medium

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Anjali Pal* & Sanjoy Kumar Maji

 

 

 

Arsine gas can reduce HAuCl4 in aqueous SDS micellar medium to produce colloidal gold nanoparticles (lmax : 530 nm). The spectrophotometric evaluation of the gold sol at 530 nm gives a direct measure of arsenic concentration.

 

 

 

 

Authors for correspondence are indicated by (*)

 

 


Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1099-1112

 

Is electrophilicity a kinetic or a thermodynamic concept?

P K Chattaraj*, U Sarkar, D R Roy, M Elango, R Parthasarathi & V Subramanian

Received 21 November 2005; accepted 20 March 2006

An understanding of the precise nature of a chemical reactivity descriptor is of utmost interest to quantum chemists. An attempt has been made here to analyze whether the electrophilicity index is a reliable descriptor of the kinetic behaviour or not. Relative experimental rates of Friedel-Crafts benzylation, acetylation and benzoylation reactions correlate well with the corresponding calculated electrophilicity values. Chlorination of various substituted ethylenes and nitration of toluene and chlorobenzene have been studied as representative examples of electrophilic addition and substitution reactions, respectively. The correlation is not very good although it improves drastically by removing a few data points to show that the electrophilicity is a kinetic quantity with inherent thermodynamic information. The correlation between the experimental and the calculated activation energies is studied for some Markovnikov and anti-Markovnikov addition reactions and it turns out to be reasonably well. Reaction electrophilicity, local electrophilicity and activation hardness are used together to provide a transparent picture of reaction rates as well as the orientation of aromatic electrophilic substitution reactions. Ambiguity in the definition of the electrophilicity is highlighted.

 

Indian Journal of Chemistry

Vol. 45, May 2006, pp. 1113-1120

 

Inclusion complex of 1,2,3-trihydroxybenzene with a- and b-cyclodextrins

T Stalin, P Vasantha Rani, B Shanthi, A Sekar & N Rajendiran*

Received 8 July 2005; revised 15 February 2006

Effect of a-cyclodextrin (a-CD) and b-cyclodextrin (b-CD) on the absorption and fluorescence spectra of pyrogallol (THB) has been discussed. The solid inclusion complex of THB with CD has been investigated by UV-visible, fluorimetry, FT-IR, scanning electron microscopy and semiempirical methods. The thermodynamic parameters (DG, DH and DS) values indicate that the inclusion processes are exothermic and spontaneous. b-CD studies reveal that THB forms 1:1 inclusion complex with b-CD. The small formation constant of THB shows that this molecule is not tightly embedded in the b-CD cavity. In b-CD medium, neutral, monoanion and dianion maxima are blue shifted as compared to in aqueous medium. Also, the pKa (pKa*) values in b-CD medium are greater than in aqueous medium. Of the two CDs, b-CD can more readily include THB than a-CD. Dual luminescence observed in a-CD shows that intramolecular hydrogen bonding interactions of THB in a-CD is greater than in b-CD. The study also shows that THB is more tightly embedded in a-CD than in b-CD.

 

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1121-1125

 

Manganese(II) complexes having pseudohalide coordination: Synthesis,IR spectroscopy and X-ray crystal structures of [Mn(L1)(NCS)2] and [Mn(L2)(NCS)2] compounds involving Schiff bases

Tapan K Karmakar, Barindra K Ghosh & Swapan K Chandra*

Received 3 October 2005; accepted 2 March 2006

The synthesis, characterisation and properties of two manganese(II) complexes with thiocyanate coordination [Mn(L1)(NCS)2] (1) and [Mn(L2)(NCS)2] (2) (L1 and L2 = tetradentate ligand, derived from bis condensation of pyridine-2-carboxaldehyde and 1,3-diaminopropane, and 2-benzoyl pyridine and 1,3-diaminopropane, respectively) is described. The magnetic moments of 1 and 2 are respectively 5.95 and 5.86 BM at 298 K, indicating high-spin (idealised t2g3eg2, S = 5/2) electronic configuration. The X-band EPR in 1:1 DMF-toluene glass (77 K) shows the 55Mn hyperfine structure at g = 2 with peak-to-peak separation of about 85 G. The structures 1 and 2 have been determined by single crystal X-ray diffraction studies, showing thereby that the manganese atom is hexacoordinated with an unusual distortion in the coordination sphere of this type of linear tetradentate ligand and thiocyanato anion acting as a terminal donor.

IPC Code: Int. Cl.8 C07C251/02; C07F13/00

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1126-1130

 

Synthesis, characterization, spectroscopic and electrochemical studies
of new thioether ligated octahedral low-spin cobalt(II) complex:
Oxidative cleavage of C-S bond

 

Chandrama Basu, Santanu Chowdhury & Soma Mukherjee*

Received 24 October 2005; revised 6 February 2006

The reaction of cobalt(II) acetate tetrahydrate with dithiaalkyl substituted aryl azo-oxime ligand HON=C(Ph)N=NC6H4S(CH2)2SC6H4N=NC(Ph)=NOH (H2PhL), 1, affords a thioether ligated octahedral low-spin [CoII(PhL)], 2, (d7, t2g6 e1, S =1/2) with CoN4S2 coordination. The room temperature magnetic moment of solid [CoII(PhL)] is 1.88 mB. The low-spin configuration is further authenticated by its eight line EPR spectra (g = 2.02, A = 31 G) in frozen acetonitrile (77 K). The complex displays a quasi-reversible (DEp = 90 mV) one-electron cyclic response in acetonitrile at 0.08 V versus saturated calomel electrode. The response is assigned to the [CoII(PhL)]/[CoIII(PhL)]+ oxidation. Moreover, the bivalent [CoII(PhL)], 2, undergoes an oxidative cleavage of the C-S bond to afford parent [CoIII(PhL)ClO4], 3, and transformed [CoIII(PhL¢)(PhL¢¢)], complexes in their trivalent state. In CDCl3, the splitting of the vinylic protons of [CoIII(PhL¢)(PhL¢¢)], 4, appears at d5.85 (dd), 5.66 (dd) and 5.58 (dd), respectively (dd = doublet of doublet). All complexes have been characterized with the help of C, H, N analysis, FAB mass, cyclic voltammetry, spectroscopic techniques (UV-vis, 1H NMR and EPR) and magnetic studies.

IPC Code: Int. Cl.8 C07F15/06

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1131-1138

 

Alkylation of phenol with tert-butyl alcohol catalysed by some
sulphated titania systems

K R Sunajadevi & S Sugunan*

Received 9 February 2005; revised 21 March 2006

Titania sulphated titania and transition metal loaded (9%) sulphated titania have been prepared by sol gel method and characterized by XRD, FTIR, BET surface area, EDX and UV-vis DRS. Surface acidity of these catalysts is determined by temperature programmed desorption of ammonia. Alkylation of phenol with tert-butanol in the vapour phase over the prepared systems has been studied at 1 atm and 160-220°C. The reaction provides high selectivity of alkylation at the para position. The product selectivity has been correlated with the surface acidity of the systems.

IPC Code: Int. Cl.8 B01J21/00; B01J37/00; C07B37/00

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1139-1143

Synthesis, characterization and thermal behaviour of ZnS4P2
chromophore as prototype

 

Shahab A A Nami, K S Siddiqi* & Yonas Chebude

Received 29 September 2005; accepted 12 March 2006

Complexes of the type M(PPh3)2(dtc)2 where M = Co(II), Ni(II), Zn(II) and Hg(II), PPh3 = triphenylphosphine and dtc = sodium diethyldithiocarbamate, have been synthesized and characterized by elemental analysis, IR, UV-vis spectroscopy, TGA/DSC, magnetic moment and conductivity measurements. On the basis of these studies, an octahedral geometry has been proposed for all the complexes. The Zn-complex exhibits two-step thermogram leading to the formation of ZnS4 as the end product at 900°C. Symmetrical bidentate coordination of the dithiocarbamato group has been observed in all the cases. Conductivity measurements of 1 mM solution of the complexes in DMSO show them to be non-electrolytes.

IPC Code: Int. Cl.8 C07F3/06

Indian Journal of Chemistry

Vol. 45, May 2006, pp. 1144-1152

Electrochemical oxidation of ethanol on thin coating of platinum
based material on nickel support

Pradip Paul, Joyeeta Bagchi & Swapan Kumar Bhattacharya*

Received 17 November 2005; revised 16 February 2006

For the development of cost effective direct alcohol fuel cells, the key point for anodic oxidation of ethanol is the search for a cheaper electrocatalyst which can effectively increase the current density and decrease the anodic overvoltage. In this respect, thin deposits of platinum and co-deposits of platinum and ruthenium on Ni- support from different baths, have been studied taking 1M ethanol in 1M NaOH solution. Polarization and chronopotentiometric studies indicate the intrinsic superiority of Ni/Pt-Ru electrodes over Ni/Pt and Ni electrodes, but the overall electrocatalytic activity of the coated electrodes follows the order: Ni/Pt(PVA) > Ni/Pt > Ni/Pt-Ru(PVA) > Ni/Pt-Ru > Ni, (where PVA is polyvinyl alcohol).              An increase in the roughness factor due to smaller size (150nm) of deposit of Pt than co-deposit of Pt and Ru under the experimental deposition condition may be the cause of the above mentioned order. Steady state polarization, cyclic voltammetry, chronopotentiometry and SEM images have been used to correlate the catalytic activity of such electrodes with the characteristics of the deposits and surface morphology.

IPC Code: Int. Cl.8 C07B33/00; C25D; H01M8/00

 

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1153-1157

 

Synthesis and spectral characterization of palladium(II) and silver(I) complexes of antipyrine-azo-imidazoles

S Senapati, Sk. Jasimuddin & C Sinha *

Received 28 October 2005; accepted 22 March 2006

Antipyrine-azo-imidazole (1) and its N(1)-alkyl derivatives (2) are synthesized and characterized spectroscopically. The ligands are N,N¢ chelator. Two groups of coordination complexes, Pd(2)Cl2 (3) and [Ag(2)2](ClO4) (4) have been synthesized and characterized by spectral (IR, UV-vis, 1H NMR) data.

IPC Code: Int. Cl.8 C07F1/10; C07F15/00; C09B45/00

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1158-1164

Kinetics and mechanism of the oxidation of organic sulphides by quinolinium bromochromate

Varsha Dhariwal, Deeksha Yajurvedi &
Pradeep K Sharma*

Received 20 October 2005; accepted 20 February 2006

The oxidation of thirty‑four sulphides by quinolinium bromochromate (QBC) has been found to result in the formation of the corresponding sulphoxides. The reaction is first order with respect to both QBC and the sulphide. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation has been studied in 19 different organic solvents. An analysis of the solvent effect by Swain's equation shows that both the cation- and anion-solvating powers of the solvents play an important role in the oxidation. The rates of oxidation meta- and para-substituted phenyl methyl sulphides have been correlated with Charton's LDR equation. The rates of the ortho-compounds show excellent correlation with the LDRS equation. The oxidation of alkyl phenyl sulphides is subject to both polar and steric effects of the alkyl groups. The polar reaction constants are negative indicating an electron-deficient sulphur centre in the slow step. A mechanism involving formation of a sulfurane intermediate in the slow step has also been proposed.

IPC Code: Int. Cl.8 C07B33/00

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1165-1169

 

Effect of DMF on the solvation behaviour of BiCl3 in CH3OH and CH3CN:
A conductometric study

J Ishwara Bhat* & T N Sreelatha

Received 21 March 2005; revised 17 March 2006

The effect of addition of dimethyl formamide on the conductivity and solvation behaviour of BiCl3 in CH3OH and CH3CN at four different temperatures has been reported. In both the solvents, the conductivity is found to decrease and the solvation is found to increase on addition of DMF at all temperatures. Kraus-Bray and Shedlovsky conductivity models have been used to evaluate the limiting molar conductance, dissociation and association constants. Ion pair formation constant and triple ion constant have also been computed. Walden product and thermodynamic parameters are also reported. Solvation number of the species of BiCl3 has been calculated in pure solvents by the mobility method.

IPC Code: Int. Cl.8  G01N

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1170-1172

Effect of side arm chain length of redox ionophores on uptake of some metal ions

Anubhuti Awasthy, Mamta Bhatnagar,
Nidhi Joshi & Uma Sharma*

Received 30 November 2005; revised 16 March 2006

Synthesis of redox switched ionophores 1-[1-anthraquino­nyloxy] 3, 6 dioxaoctane-8-methane (A1) and 1-[1-anthraquino­nyloxy] 3 oxapentane-5-methane (A2) has been reported. These ionophores have been used as carriers in liquid membrane transport and extraction studies of alkali and alkaline earth metal ions. The sequence of metal ions extracted and transported in oxidised and reduced state by ionophore A1 is: Ca2+>K+>Li+>Mg2+ and Li+>K+>Ca2+>Mg2+ respectively. The order of extraction and transport of metal ions with respect to ionophore A2 is Li+>K+>Ca2+ and Ca2+>K+>Li+ respectively. Ionophore A1 is selective for Ca2+ while ionophore A2 is selective for Li+ ions. This selectivity may be used in ion selective electrode and redox switchable devices.

IPC Code: Int. Cl.8  C07C59/00; G01N

Indian Journal of Chemistry

Vol. 45A, May 2006, pp. 1173-1177

Voltammetric determination of dna based on its interaction with neutral red

Wei Sun*, Jiayu You, Qingxiang Wang & Kui Jiao

Received 16 August 2005; revised 9 March 2006

A new linear sweep voltammetric (LSV) assay of fsDNA based on its interaction with neutral red (NR) is presented. At pH 8.0 Britton-Robinson (B-R) buffer solution, the dye can bind with DNA to form a supramolecular complex, which results in the decrease of the linear sweep voltammetric reductive peak current at -0.60 V (vs. SCE) on the mercury electrode. The binding reaction is completed within 20 min at room temperature and remains stable for at least 2 hours. The optimal conditions for the binding reaction and the electrochemical detection have been determined. Under the optimal conditions there is little interference from most metal ions and amino acids. The calibration graph for fsDNA is linear in the range of 1.0~30.0 mg/L with the linear regression equation as ΔIp"(nA)=28.20C (mg/L)+10.84 (n=9, γ=0.992) and the detection limit as 0.67 mg/L. The interaction mechanism is characterized by the aggregation of DNA-NR supramolecular complex by UV-vis absorption spectrophotometry and cyclic voltammetry. The stoichiometry of this supramolecular complex has been calculated with the binding number as 1.5 and the binding constant as 1.73×107.

IPC Code: Int. Cl.8 G01N27/00; C12Q/68

 

Indian Journal of Chemistry A

Vol. 45A, May. 2006, pp. 1178-1182

Spectrophotometric determination of arsenic via nanogold formation in micellar medium

Anjali Pal* & Sanjoy Kumar Maji

Received 15 March 2005; revised 9 March 2006

Colloidal gold nanoparticles are formed in aqueous anionic micellar medium by the quantitative reduction of chloroauric acid (HAuCl4) by arsine (AsH3) gas produced from arsenic bearing sample water. The absorbance of the pink gold sol (lmax at 530 nm) is a measure of arsenic concentration present in the sample. Both, As(III) and As(V) either present individually or in mixture could be determined. The molar absorptivity is 6.1´103 lit mol-1 cm-1 and the Sandell sensitivity is 1.28´10-2 mg cm-2. The gold particles, as observed from the transmission electron microscopy analysis, are spherical in nature, the average size being 14±5 nm. The linear dynamic range (LDR) for the arsenic determination is 0-0.5 ppm (0-6.67´10-6 M). The limit of detection (LOD) is 0.005 ppm. The 95% confidence limit for 0.2 ppm of arsenic is 0.207± 0.007 ppm (for 10 replicates). The relative standard deviation (RSD) is <±5%. The method is free from the common interferences, Fe2+/Fe3+, Ca2+/Mg2+, PO4-3, SiO3-2, NO3-, Cl-, SO4-2, humic acid, common herbicides/pesticides like 2,4-D, endosulfan, atrazine, etc. and can be applied for the determination of total arsenic concentration in real water samples. The results are in good agreement with the SDDC method. The toxic and volatile organic solvents used for silver diethyldithiocarbamate method could be avoided in this method and hence it is safer, much easier and more reproducible.

IPC Code: Int. Cl.8 G01N21/00