Chlorophenoxy acid silvex

Chlorophenoxy acid 2,4-D, silvex Sample acidified with H3P04, analytes... 

These herbicides are highly selective for hroadleaved weeds. 2,4-D was the first chlorophenoxy acid herbicide developed. There are several compounds that belong to this group in addition to 2,4-D and they include 2,4-DB, Di-chlorprop, MPCA, MPCB, MCPP, 2,4,5-T, and 2,4,5-TP (Silvex). 

Analysis of Chloronhenoxv Herbicides. Many important target environmental pollutants can only be detected via conventional GC methods by first converting them to derivatives that are less polar and more volatile, e.g., the chlorophenoxy herbicides. A standard EPA method (SW-846 8150) specifies soil extraction and alkaline hydrolysis of any esters present followed by (re) esterification via diazomethane and detection and confirmation by GC/MS. The methylation step is required because the free carboxylic acids will not pass through conventional GC analytical columns. Reversed phase chromatography functions equally well to resolve free carboxylic acids or the corresponding esters and thus can eliminate the diazomethylation step. An interlaboratory check sample provided by the EPA of soil spiked with the chlorophenoxy acid herbicides Silvex and 2,4-D was obtained by our laboratory to demonstrate that LC/MS can offer a simpler and effective method for these compounds. 

Chlorophenoxy acid herbicides, such as, 2,4-D, silvex, or 2,4,5-T — In these compounds, the alkyl group of a lower carboxylic acid usually acetic or propionic acid is attached to a chlorophenoxy moiety as follows ... 

Chlorophenoxy acids and their derivatives constitute a major class of herbicides used for controlling weeds in cereal croplands, lawns, turfs, pastures, forests and in non-croplands near water. Some common herbicides of this class include 2,4-D, Silvex, 2,4,5-T,... 

This substance is moderately toxic by oral route. The oral LD50 values published in the literature vary. The LD50 (oral) in rat is with in the range of 700 mg/kg, comparable to that of Silvex. The toxic symptoms are similar to those of other chlorophenoxy acids. Contact with skin or eye can cause irritation. The vapor is irritant to mucous membranes and upper respiratory tract. 

The second case taken from the author s own work uses LLE to initially clean up an aqueous sample taken from the environment that might contain, in addition to the analyte of interest, other organic compounds that may interfere in the determinative step (9). The analytes of interest are the class of chlorophenoxy herbicides (CPFIs) and includes 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4,5-trichlorophenoxypropionic acid (Silvex). CPFIs are... 

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