Preconcentration and Determination of Chromium Species Using Octadecyl Silica Membrane Disks and Flame Atomic Absorption Spectrometry

2007 ◽  
Vol 25 (12) ◽  
pp. 1859-1865 ◽  
Author(s):  
Ali MOGHIMI ◽  
Mohammad SABER-TEHRANI ◽  
Syed WAQIF-HUSAIN ◽  
Majid MOHAMMADHOSSEINI
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.


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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