S. K. Saxena

Effect of Different Factors on the Movement of Some Amino Acids in Soils Using Thin-Layer Chromatography

Abstract The influence of organic matter, CaCo3, saline and alkaline salts, flyash, exchangeable cations and pH on the mobility of monocarboxylic, dicarboxylic, basic and aromatic amino acids has been studied using soil thin-layer chromatographic technique in two different type of soils. The mobility was expressed in terms of Rf, RB, and RM values. The variation in Rf, RB and RM values of anino acids under different treatments have been reported and discussed on the basis of adsorption and leachability.

Effect of Different Saline, Alkaline Salts, Fertilizers and Surfactants on the Movement of Some Carbamoyl Group Containing Pesticides in Soils

Abstract The influence of organic matter, calcium carbonate, flyash, saline and alkaline salts, inorganic fertilizers, surfactants and exchangeable ions on the mobility of five carbamoyl group containing pesticides has been studied using soil thin-layer chromatography. The variations in the Rf, RB and RM values of aldicarb, bavistin, carbofuran, dimecron and oxamyl under different treatments are reported and explained on the basis of adsorption and leachability.

Adsorption thermodynamics of carbofuran on acid and base saturated soils

The adsorption of carbofuran on hydrogen, sodium, and calcium saturated soils has been studied at 25 and 50 degrees C. The adsorption data for all types of soils is in close agreement with Freundlich isotherms and yielded S-class isotherms. The maximum adsorption was observed in acid saturated soil. Therefore, it has been in accordance with the partial molal free energy changes (F) and Kd values. The adsorption has been lower at higher temperatures. The thermodynamic constant (KO), standard free energies (delta G degree), enthalpies (delta H degree), and entropy changes (delta S degree) have been calculated for predicting the nature of adsorption.

Separation and Detection of Some Phenoxyacid Herbicides and Plant Growth Regulators by Ion-Pair Reversed-Phase Thin-Layer Chromatography

Abstract Separation and detection of phenoxyacid herbicides such as 4-chlorophenoxyacetic, 2,4-dichlorophenoxyacetic, phenoxyacetic, 2,4,5-trichlorophenoxyacetic, trichloroacetic acids and plant growth regulators such as benzoic, cinnamic, gallic, indole-3-acetic, indole-3-propionic, α-naphthaleneacetic, β-naphthalenaecetic, β-naphthoxyacetic acids have been made by ion-pair reversed-phase thin-layer chromatography on calcium sulphate coating impregnated with an ion-pair reagent cetrimide and different oils such as coconut oil, olive oil, paraffin oil and silicon oil using distilled water as a solvent and bromophenol blue as a detector.

Movement of carbofuran (nematicide) in soil columns.

Adsorption and movement of carbofuran (a systemic nematicide) were studied using two Indian soils (clay loam and silt loam) of alluvial origin. Equilibrium adsorption coefficient (K) values measured using a batch-slurry technique follows the order clay loam greater than silt loam soil. The distribution coefficients (Kd) for both the soils in batch adsorption as well as in columns were also calculated. Carbofuran movement in soil columns during water infiltration in both air-dried and water-saturated columns was estimated. The order was as anticipated from K and Kd values. A larger amount of water was needed for leaching the carbofuran to 152 cm in clay loam soil than in silt loam soil. Carbofuran appears to increase in drier soils and in finer textured soils.

Sequential thin-layer chromatography of 2,4-D and related compounds

Abstract Separations and identification of carboxylic herbicidal substances such as 2,4-dichlorophenoxyacetic acid, trichloroacetic acid, 2,4,5-trichlorophenoxyacetic acid and plant growth regulators such as benzoic acid, cinnamic acid, indole-3-acetic acid, β-naphthaleneacetic acid, β-naphthoxyacetic acid, phenoxyacetic acid have been made by sequential thin-layer chromatography on calcium sulphate layer with acetone, benzene, carbon tetrachloride, chloroform, ethyl acetate, dioxan, propanol as solvents and bromophenol blue as detector.

Movement of Phosphamidon in Soil Columns

Abstract Adsorption and movement of phosphamidon, a systemic non-ionic insecticide, was studied using two different types of Indian soil, clay loam and silt loam, of alluvial origin. Equilibrium adsorption coefficient, K, values determined by batch slurry technique were in the order: clay loam>silt loam. The distribution coefficient, Kd , for both soils in batch adsorption as well as in columns was also calculated. The phosphamidon movement measured in soil columns during water infiltration was in the order: silt loam > clay loam. This order was anticipated from the K and Kd values. A larger amount of water was needed for leaching the phosphamidon to 60 inches in clay loam than in silt loam soil.

A new indicator and test paper for the semi-quantitative determination of carbaryl in traces in water.

Abstract A chromatographic paper impregnated with sodium hydroxide (test paper), when spotted with a carbaryl solution and dipped in 2,6-dichloroquinone-4-chloroimine (Gibbs reagent) in benzene, turns blue with a violet tinge. The colour formation is based upon the hydrolysis of carbaryl to give 1-naphthol which reacts with 2,6-dichloroquinone-4-chloroimine to produce indophenol that turns blue with a violet tinge in alkaline medium. The test paper can be successfully used for the detection and semi-quantitative determination of carbaryl at ppm levels in water.

Effect of Different Salt Leachates on the movement of some Carbamoyl Groups Containing Pesticides in Soils using Thin-Layer Chromatography

Abstract The influence of pH, leachates of alkaline and saline salts, inorganic fertilizers and surfactants on the mobility of five carbamoyl group containing pesticides, viz. aldicarb, bavistin, carbofuran, dimecron and oxamyl has been studied using soil thin layer chromatographic technique. The variation in the movement of pesticides under different solvent amendments expressed in terms of Rf, RB and RM values and explained on the basis of adsorption and leachability.

Studies of thermodynamics of phosphomidon on fly ash

Adsorption thermodynamic studies of phosphomidon on fly ash at 25° and 50°C have been analysed as adsorption isotherms, Freundlich equations, Kd values and various other thermodynamic parameters. These data were in close agreement with Freundlich isotherms and yield ‘S’ type isotherms at both the temperatures. Thermodynamic constants (Ko) and standard free energy (ΔG°), enthalpy (ΔH°) and entropy changes (ΔS°) have been calculated for predicting the nature of adsorption.