scholarly journals Determination of Copper in Water and Plant Samples by Flame Atomic Absorption Spectrometry After Preconcentration on Octadecyl Silica Membrane Disks Modified with a Recently Synthesized Schiff's Base

2008 ◽  
Vol 91 (4) ◽  
pp. 865-870 ◽  
Author(s):  
Tayebeh Shamspur ◽  
Ali Mostafavi ◽  
Iran Sheikhshoaie

Abstract A simple, selective, reliable, and sensitive method for the determination of trace amounts of Cu2+ ions in aqueous samples is proposed. The Cu2+ ions are adsorbed quantitatively during the passage of aqueous samples through an octadecyl (C18) silica membrane disk modified by a symmetrical tetradentate Schiff base ligand, N,N'-bis(4-phenylazo salicylaldimine) 3-chloro-1,2-phenylenediamine (H2L). The retained Cu2+ ions were then stripped from the disk by elution with the minimal amount of nitric acid solution and determined by flame atomic absorption spectrometry. Various parameters, such as the effect of pH, flow rate, type and amount of eluent, and the effects of various cationic interferences on the recovery of ions were studied. The proposed method permitted large enrichment factors (about 550 and higher). The limit of detection of the method was 1.5 102 g/L. The use of the same disk modified with 6 mg H2L for at least 30 times showed no change in the recovery of Cu2+ ions. The accuracy of the method was confirmed by determination of Cu2+ ions in standard samples [National Institute of Environmental Studies (NIES) No. 2 and Nippon Keikinzoku Kogyo (NKK) No. 920]. The results demonstrated good agreement with certified values.

2018 ◽  
Vol 33 (2) ◽  
pp. 61
Author(s):  
M. Shabany ◽  
Ali Mohammad Haji Shabani ◽  
Shayessteh Dadfarnia ◽  
Alireza Gorji ◽  
S. H. Ahmadi

A procedure for separation and preconcentration of trace amounts of Zn(II) from aqueous media is proposed. The procedure is based on the adsorption of Zn2+ on octadecyl bonded silica membrane disk modified with N,N’-disalicylidene-1,2-phenylendiamine at pH 7. The retained zinc ions were then stripped from the disk with a minimal amount of 1.5 mol L-1 hydrochloric acid solution as eluent, and determined by flame atomic absorption spectrometry. Maximum capacity of the membrane disk modified with 5 mg of the ligand was found to be 226 μg Zn2+. The relative standard deviation of zinc for ten replicate extraction of 10 μg zinc from 1000 mL samples was 1.2%. The limit of detection of the proposed method was 14 ng of Zn2+ per 1000 mL. The method was successfully applied to the determination of zinc in natural water samples and accuracy was examined by recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry (GFAAS).


2006 ◽  
Vol 3 (2) ◽  
pp. 89-98 ◽  
Author(s):  
Mohammad Saber Tehrani ◽  
Majid Mohammadhosseini

An efficient procedure for pre-concentration, separation and determination of the trace amounts of lead (II) ions in water samples has been established. The analyte is adsorbed on the surface of C18 silica membrane disk modified with APDC, quantitatively, while other interfering ions pass through the disk to drain. The sorbed Pb2+ ions are then stripped by appropriate eluting agents followed by monitoring of the eluates by flame atomic absorption spectrometry (FAAS). The effects of sample pH, amount of the modifier, stripping agent types, sample flow-rates, and potential interfering ions were also investigated. The described method involves a pre-concentration factor of about 200. The detection limit of the procedure is 0.93 ng.mL-1. The method was employed for isolation and determination of lead in different water samples.


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