Spectrophotometric determination of dissociation constants of selected acidic herbicides

Cessna, Allan J.; Grover, R.

doi:10.1021/jf60215a024

Cited by 59 publications

(25 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence above zero point charge (pH zpc ), the particle surface is positively charged and vice versa. The reported pKa value of dinoseb is 4.62 [31]. As shown in Figure 5, the degradation of dinoseb was studied between pH 2 to 11, and efficient degradation was found at acidic pH of 5.1; the results are in good agreement with previously reported results on the degradation of 2,4-dinitrophenol in presence of ZnO [32].…”

Section: Resultssupporting

confidence: 88%

Photoassisted Degradation of a Herbicide Derivative, Dinoseb, in Aqueous Suspension of Titania

Mir

Haque

Khan

et al. 2012

The Scientific World Journal

View full text Add to dashboard Cite

The titanium dioxide (TiO2) photoassisted degradation of herbicide dinoseb has been examined in aqueous suspensions under UV light irradiation. The degradation kinetics were studied under various conditions such as substrate concentration, type of catalyst, catalyst dosage, pH, and light intensity as well as in presence of electron acceptors such as hydrogen peroxide, potassium bromate, and potassium persulphate under continuous air purging, and the degradation rates were found to be strongly influenced by these parameters. The Degussa P25 was found to be more efficient photocatalyst as compared to other photocatalysts tested. Dinoseb was found to degrade efficiently in acidic pH and all the electron acceptors studied enhanced the degradation rate. The results manifested that the photocatalysis of dinoseb followed pseudo-first-order kinetics. A qualitative study of the degradation products generated during the process was performed by GC-MS, and a degradation mechanism was proposed.

show abstract

Section: Resultssupporting

confidence: 88%

Photoassisted Degradation of a Herbicide Derivative, Dinoseb, in Aqueous Suspension of Titania

Mir

Haque

Khan

et al. 2012

The Scientific World Journal

View full text Add to dashboard Cite

show abstract

“…In initial experimental work, three sets of acidic compounds were used in the CE separation using α‐CD: (i) positional isomers of C and M, (ii) positional isomers of DC and DM, and (iii) four phenoxy acids (MCPB, 2,4‐DB, MCPA, and 2,4‐D). With p K a < 4.9 for all test analytes , each analyte in the pH 9.2 buffer used here is negatively charged. Figure shows an example of the obtained electropherograms for simultaneous separation of each set of the analytes, C/M, DC/DM, and phenoxy acids, with and without the addition of α‐CD.…”

Section: Resultsmentioning

confidence: 99%

Separation selectivity patterns of fully charged achiral compounds in capillary electrophoresis with a neutral cyclodextrin

Soonthorntantikul

Srisa-Art

Leepipatpiboon

et al. 2012

J of Separation Science

View full text Add to dashboard Cite

Based on the separation selectivity equation, related to the dimensionless parameters for fully charged achiral analytes using a neutral CD, the separation selectivity can be classified into seven patterns. With respect to CZE without CD, the presence of CD in the buffer may improve, or reduce, the separation selectivity with this effect being accompanied by the same or reversed electrophoretic mobility order for charged analytes. This can depend on the separation selectivity of the two analytes in free solution, the binding selectivity, the separation selectivity of analyte-CD complexes and the ratio of electrophoretic mobility of the analytes in free, and complexed forms. Using positional isomers of benzoic acids and phenoxy acids as test analytes and α-CD as a selector, the observed separation selectivity shapes were found to be in excellent agreement with the predicted separation selectivities.

show abstract

“…Previous studies (unpublished data) using radiolabeled 2,4-D had indicated that the phenoxy herbicide was sorbed to this precipitate at a pH of 1 and was not completely removed during the diethyl ether extraction. Thus, to minimize such losses in the present study, the pH of the alkaline extract was initially lowered to pH 5 so that mecoprop remained in solution while the precipitate formed (pK, = 3.1 for mecoprop; Cessna and Grover, 1978). The precipitate was then removed by centrifugation.…”

Section: Resultsmentioning

confidence: 99%

Comparison of extraction/hydrolysis procedures for the determination of acidic herbicides in plants: residues of mecoprop in barley following postemergence application

Cessna¹

1992

J. Agric. Food Chem.

Self Cite

View full text Add to dashboard Cite

Two extraction/hydrolysis procedures for the determination of acidic herbicides in plant tissue were compared for the analysis of mecoprop residues in barley tissue. It was found that organic solvent extraction followed by alkaline hydrolysis was less tedious and time-consuming and provided better recoveries than an extended alkaline extraction/hydrolysis. Following a postemergence application of mecoprop at 1.1 kg ha-l to barley at the 5-leaf stage, initial residues were on the order of 100 mg kg-l. Six weeks after application, whole plant (above ground) residues had decreased to 0.1-0.2 mg kg-l. At maturity, residues in the straw were <0.1 mg kg-l, and residues, at the limit of quantification of 0.05 mg kg-l, were not detected in the seed.

show abstract

Spectrophotometric determination of dissociation constants of selected acidic herbicides

Cited by 59 publications

References 19 publications

Photoassisted Degradation of a Herbicide Derivative, Dinoseb, in Aqueous Suspension of Titania

Photoassisted Degradation of a Herbicide Derivative, Dinoseb, in Aqueous Suspension of Titania

Separation selectivity patterns of fully charged achiral compounds in capillary electrophoresis with a neutral cyclodextrin

Comparison of extraction/hydrolysis procedures for the determination of acidic herbicides in plants: residues of mecoprop in barley following postemergence application

Contact Info

Product

Resources

About