Carbofuran In Samples Research Articles

OPTIMIZATION OF SOLID-LIQUID EXTRACTION WITH THE LOW TEMPERATURE PARTITION FOR THE DETERMINATION OF CARBOFURAN IN SUGAR CANE

The broad application of cabofuran pesticide in sugar-cane cultures and its high toxicity makes it essential a search for new methods of preparing the samples to analysis of this pesticide in this culture. This work tried to optimize the solid-liquid extraction technique with low temperature partitioning (SLE/LTP) to determine the carbofuran in samples of sugar cane. The SLE/LTP technique, is a simple technique that shows advantages regarding other extraction techniques. Being so, a factorial experimental design 23 was created to study the simultaneous behavior of three factors in two levels. After this stage of split, to split, identification and qualification of carbofuran was analyzed the supernatant using the high efficiency of liquid chromatography with ultraviolet detector (HPLC/UV). The method ´s efficient to the extraction of carbofuran from sugar cane with percentages of recovery over the 73,0 %. After optimizing, the technique was applied in real samples of sugar cane in the region of Itumbiara-GO, Brazil. No carbofuran residues were found in the analyzed samples or they were below the detection limit. The SLE/LTP technique optimized to sugar cane, showed to be simple and efficient, being a economic method, consuming a little amount of sample and solvent extractor.

Online microchannel preconcentrator for carbofuran detection

A simple and rapid online microchannel preconcentrator coupled with an amperometric detection for the analysis of carbofuran using polyethylene glycol coated onto magnetic particle (PEG-magnetic particles) sorbents was developed. This simple-to-prepare microchannel preconcentrator used an external magnet to retain the PEG-magnetic particle sorbents inside the microchannel. Under optimum conditions, the system provided two linear ranges, from 0.01 to 10.0 mg L−1 and from 10.0 to 130.0 mg L−1 with a limit of detection of 8.7 ± 0.1 μg L−1. The microchannel preconcentrator provided very good stability; it can be used for up to 326 consecutive injections of 5.0 mg L−1 carbofuran with a relative standard deviation of less than 3%. The developed system provided a good microchannel-to-microchannel and a good electrode-to-electrode reproducibility (n = 6, %RSD < 1). It also provided an excellent selectivity when it was tested with two other carbamate pesticides, carbaryl and methomyl, with a 43 and 256 times higher detection sensitivity for carbofuran, respectively. The developed system was successfully applied to detect carbofuran in surface water samples obtained near vegetable plantation areas. The concentrations of carbofuran in these samples were found to be in the range of non-detectable to 0.047 ± 0.001 mg L−1. The developed system is easy to operate and easy to couple with other analytical instruments and it could be easily adapted for the analysis of other polar organic contaminants.

Layer-by-Layer self-assembled acetylcholinesterase/PAMAM-Au on CNTs modified electrode for sensing pesticides

In this paper, an acetylcholinesterase (AChE)/dendrimers polyamidoamine (PAMAM)-Au/Carbon nanotubes (CNTs) multilayer modified electrode based on LbL self-assembled technique was employed in the detection of carbofuran in samples. The configuration of the nanostructure on the electrode provided a favorable environment to the immobilization of AChE. The modified films also improved the electrocatalytic characteristics and electron transfer speed between the films and the surface of electrode. The PAMAM-Au nanoparticles were characterized by SEM and UV-VIS methods. A set of experimental conditions were also optimized for the detection of the pesticides. A linear response over carbofuran concentration in the range of 4.8x10(-9)M to 0.9x10(-7)M was exhibited with a detection limit of 4.0x10(-9)M. The biosensor showed high sensitivity, good stability and reproducibility with promising application.

Adsorption/desorption and mobility of carbofuran in soil samples from Kenya.

Carbofuran (2,3-dihydro-2-2-dimethyl-7-benzofuranyl-Nmethylcarbamate) is a very effective systemic and contact insecticide and nematicide used against a wide range of agricultural pests (Aquino and Pathak, 1976; Caro et al., 1973). Though less persistent than most organochlorine pesticides, carbofuran is more toxic to animals, it is very soluble in water and tends to degrade faster under flooded soil conditions (Caro et al., 1973; Venkateswarlu et al., 1977; El-Zorgani et al., 1980). The adsorption and desorption characteristics which determine the movement of pesticides through the soil profile, their bioavailabiltiy, microbial degradability and persistence depend upon the soil properties such as organic matter content, clay content and the physical/chemical properties of the pesticide i.e. size, shape, solubility in water, pK values and polarity (Wondimagegnehu and Foy, 1986; Calderbank, 1989). In Kenya, carbofuran is used extensively against rice pests in paddy fields and because of its acute toxicity the fate of its residues in terms of their persistence and mobility is of great concern (Anonymous, 1985; Plimmer, 1980). The aim of this study was to investigate the adsorption/desorption and mobility of carbofuran in samples of soil collected from the Ahero and Chiromo areas of Kenya. MATERIALS AND METHODS The two soils used in this study were collected from two different agricultural regions of Kenya i.e. the lowland heavy, sandy soils of the Kano Plains at Ahero and the red, silt loam soils from Chiromo in Nairobi. A third soil was a standard sandy soil obtained from the Institute of Ecological Chemistry, GSF, Munich. The composition and physical characteristics of the three soils are presented in Table 1. The soil samples were air-dried in the laboratory, ground with mortar and pestle and sieved through a 2 mm mesh.