Group speciation of metal dithiocarbamates by sorption on C60 fullerene

Abstract

A simple flow injection system for the on-line preconcentration of metal dithiocarbamates (fungicides) by sorption on a C 60 fullerene column was developed. Neither the acid hydrolysis needed by the conventional method to release CS 2 nor derivatization is required as the fungicides are directly retained on the sorbent column and subsequently eluted from it with dilute HNO 3 . The eluted fraction is directly fed into a flame atomic absorption spectrometer. Group speciation can be done according to the metals present in the dithiocarbamate (viz., dithiocarbamates of Zn 2+ , Mn 2+ , or Fe 3+ ) but no within-group discrimination is possible (ziram, zineb and propineb provide a global response). The analytical figures of merit of the proposed method are as follows: limits of detection (3s) from 1 to 5 ng ml 21 ; precision (RSD) ca. 2.5%; and preconcentration factor 45 (using 10 ml of sample). No interference from metals such as Zn, Mn or Fe, as inorganic salts, was observed. The method was applied to the resolution of synthetic mixtures as well as to the speciation/determination of ziram, maneb and ferbam in spiked grain samples, all with acceptable recoveries. Experimental ApparatusA Perkin-Elmer 380 atomic absorption spectrometer equipped with a bead impact system in the burner chamber and with an

Fabrication and characterization of carbon nanotubes immobilized in porous polymeric membranes

“…[2][3][4] They demonstrate excellent gas and liquid phase retention of a variety of organic molecules and have been self assembled as high resolution gas chromatography stationary phases. [5][6][7][8] The main advantage of CNTs is that their high aspect ratios lead to large specific surface areas.…”

Development of a derivative spectrophotometric method for the determination of fungicide zinc ethylenebisdithiocarbamate using sodium molybdate

“…Many methods like spectrophotometry, 1,[3][4][5][6][7][8] flame atomic absorption spectrometry 9,10 FT-IR, 11 gas chromatography, 12,13 HPLC, [14][15][16] polarography, 17,18 biosensors, 19 and enzyme linked immuno sorbent assay 20 are available for Zineb determination and other dithiocarbamates. Most of the applied methods use different techniques like spectrophotometry and gas chromatography 3 based on analysis of CS 2 , H 2 S or amines which are evolved by the decomposition of EBDCs.…”

Flow Injection/Atomic Absorption Spectrometric Determination of Zineb in Commercial Formulations of Pesticide Based on Slurry Sampling

“…Ulakhovich et al 14 determined zineb in fruits, vegetables and aqueous samples by voltammetry after its solvent extraction with CH2Cl2, while Marty and Noguer 15 explored the inhibition effect of zineb on the aldehyde dehydrogenase enzyme for its determination by amperometry. More recently, Baena et al 16 used a C60 fullerene column for zineb preconcentration (among other dithiocarbamate pesticides) in a flow system. After elution with a 0.2 mol l -1 HNO3 solution, the pesticide was injected in a flame AAS and the zinc was detected for quantification purposes.…”

“…[9][10][11] During the last ten years, direct determinations of zineb (without hot acid decomposition) have also been carried out by spectrophotometry, 12,13 voltammetry, 14 amperometry 15 or flame atomic absorption. 16 Malik et al 12 and Kapoor and Rao 13 carried out spectrophotometric determinations of zineb, converting the pesticide into zinc-phenylfluorone and zinc-PAR (4-(2-pyridilazo)resorcinol) complexes, respectively. Ulakhovich et al 14 determined zineb in fruits, vegetables and aqueous samples by voltammetry after its solvent extraction with CH2Cl2, while Marty and Noguer 15 explored the inhibition effect of zineb on the aldehyde dehydrogenase enzyme for its determination by amperometry.…”

“…Afterwards, other researchers applied the same approach, just detecting the CS2 formed by several other instrumental techniques, such as head space gas chromatography, 6 differential pulse polarography, 7 Fourier-transform infrared spectrometry 8 or UV-visible spectrophotometry. [9][10][11] During the last ten years, direct determinations of zineb (without hot acid decomposition) have also been carried out by spectrophotometry, 12,13 16 used a C60 fullerene column for zineb preconcentration (among other dithiocarbamate pesticides) in a flow system. After elution with a 0.2 mol l -1 HNO3 solution, the pesticide was injected in a flame AAS and the zinc was detected for quantification purposes.…”