Water triazine degradation products

Chemistry and Transport of Triazine Degradation Products in Water 469... 

The analysis of highly polar molecules in water samples at the trace level is often limited by the efficiency of the extraction procedures. Due to their high solubility in water, these molecules are frequently not sufficiently retained in the stationary phases of the chromatographic or solid-phase extraction supports. Immunochemical techniques present an advantage to allow direct measurements in aqueous media. Therefore, it is necessary to develop screening methods to efficiently monitor contamination by these triazine degradation products. 

Several reported SPE procedures for triazine compounds and some of their degradation products in water are also shown in Table Although the C-18 SPE... 

Kaune, A., Bruggemann, R., and Kettrup, A. High-performance liquid chromatographic measurement of the 1-octanol-water partition coefficients of s-triazine herbicides and some of their degradation products, J. Chromatogr. A, 805 (1-2) 119-126. 1998. 

Muir, D.C.G. and Baker, B.E. Detection of triazine herbicides and their degradation products in tile-drain water from fields under corn (maize) production, J. Agric. Food Chem., 21(1) 122-125, 1976. 

Liquid chromatography -APCI-MS is applicable to many different types of pesticide structures, such as triazines, phenylurea herbicides, acetanilides, and OPPs. A study of 12 pesticides and pesticide degradation products demonstrated the sensitivity of the technique for OPP determination, with detection limits for water samples of about 0.001-0.005 /zg/L (32). 

Saez, A., D. Gomez de Barreda, J. Garcia de la Cuadra, E. Lorenzo, and C. Peris (1996). UV detection of triazine herbicides and their hydroxylated and dealkylated degradation products in well water. J. Chromatogr. A, 721 107-112. 

A Decade of Measuring, Monitoring, and Studying the Fate and Transport of Triazine Herbicides and their Degradation Products in Groundwater, Surface Water, Reservoirs, and Precipitation by the US Geological Survey... 

A number of major studies to analyze triazine herbicides and their degradation products (i.e., metabolites) in water have been carried out by the United States Geological Survey (USGS), Water Resources Division, in the Toxic Substances Hydrology Program. These studies investigated four major water resources - groundwater, surface water, reservoirs, and precipitation. 

Table 30.3 Percent detections of triazine herbicides and degradation products in surface water of the midwestern United States during 1989-1990 ...

This section discusses the occurrence of the degradation products of atrazine, cyanazine, simazine, propazine, prom-etryn, and prometon, as well as their degradation pathways from soil into surface water. More detailed discussion of triazine degradation can be found in several other chapters of this book. 

An important finding of USGS research was the occurrence of triazine herbicides in surface water. In a study by Thurman et al. (1991, 1994) measurable amounts of atrazine, the most frequently detected herbicide, occurred in 91% of the pre-planting samples, 98% of the post-planting samples, and 76% of the harvest samples. The atrazine degradation product DEA was found in many of the samples that contained atrazine. The frequency of detection or apparent order of stability of the herbicides and their degradation products is as follows atrazine, DEA, DIA, and cyanazine. This stability order is based on results of field-dissipation studies on atrazine and cyanazine (Meyer, 1994 Mills and Thurman, 1994). 

Sabik, H., Jeannot, R., and Rondeau, B., Multiresidue methods using SPE techniques for monitoring priority pesticides, including triazines and degradation products, in ground and surface waters, J. Chromatogr. A, 885, 217-236, 2000. 

Some triazines, including atrazine and simazine, were extracted from water by SEE after preconcentration on sohd-phase extraction disks.The freeze-dried residue or SPE disk was then introduced into the extraction cell and eluted with either pure CO2 or methanol or acetone-modified CO2. SEE has been applied in combination with online sohd-phase extraction for pesticides, including triazines. However, this technique is still used mainly on solid matrixes. The main limitation with aqueous matrixes remains the miscibility of water with supercritical carbon dioxide. Recoveries of nonpolar pesticides, extracted by SEE technique using octacedyl-bonded silica, are generally effective with CO2 elution alone. This is not the case for semipolar and polar compounds, such as triazines and their degradation products. For example, the addition of... 

Methanol is usually utilized to prewet the Cjg Bond-Elut columns and opens the hydrophobic chains to increase the effective surface area. Water samples are also fortified with at least 1% methanol to continuously wet the stationary phase. This can improve recovery rates for a large number of herbicides, including triazines. By contrast, degradation products, which are often more polar than parent compounds, may not be retained as effectively in the presence of a modifier. Ground and surface water must always be filtered prior to the extraction of pesticides with the SPE technique. Prefiltering will not affect the determination of herbicides and their degradation products, since these compounds exhibit a log ATqc near 2 and consequently they are largely (99.5%) distributed in water in the dissolved phase. ... 

Sorbent-analyte interactions fall into three categories nonpolar, polar, and ionic. Nonpolar sorbents are generally selected for extracting triazines from water. By contrast, degradation products containing polar functional groups such as, hydroxyl, carbonyls, amines, and sulfhydryls, need polar sorbents. 

Different types of sorbents have been employed in SPE techniques to extract triazines, phenylureas, some methylcarbamates, triazoles, chlorophenoxy acid compounds, and their degradation products from water. The most widely used are Cg and Cjg chemically-bonded to silica, carbon black, and polymeric resins (such as PLRP-S). The most polar compounds, like DIA, DEA, HA, and metribuzin, have low breakthrough volumes with these sorbents, except... 

M., Interlaboratory vahdation of solid-phase microextraction for the determination of triazine herbicides and their degradation products at ng/1 level in water samples, J. Chromatogr. A, 795, 371-376, 1998. 

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