Degradation products assessing

Routledge, E.J. and Sumpter, J.P. (1996). Estrogenic activity of surfactants and some of their degradation products assessed using a recombinant yeast screen. Environmental Toxicology and Chemistry 15, 241-248. 

The ECPI approach has been adopted by the European Commission in their "Technical Guidance Document on the Risk Assessment of Notified New Substances" as the model for assessment of environmental exposure from additives in plastics. It is important to note, however, that due to the effect of ultraviolet degradation and microbial attack, a significant proportion of the emissions from flexible PVC consists of plasticizer degradation products. In these instances, therefore, the level of plasticizers appearing in the environment will be significantly less than indicated by the plasticizer loss data. 

In addition, dehydrogenated structures were found to cause a hypsochromic shift. Since, with the exception of neobetanin, these betacyanin degradation products were found not to be native to betalain crops, it is suggested that these peculiar structures may be used as heat indicators to assess the thermal loads of the respective products have undergone during production. 

The Green Screen includes a chemical s breakdown products, that is, metabolites and degradation products in a hazard assessment because they may be more hazardous than the parent compound. The final benchmark for a parent chemical is the lowest benchmark achieved by either it or its breakdown products. For example, if a parent chemical achieved Benchmark 2, but its breakdown product achieved Benchmark 1, the final benchmark for the parent chemical is Benchmark 1. Thus the degradation product or metabolite of a chemical is considered equivalent to the parent compound with respect to its benchmark unless it can be demonstrated that the breakdown product is insignificant (i.e., transient, not actually formed, etc.). 

To select and define the target analytes for the residue analysis of crops in a field trial, applicants should consider metabolites/degradation products of the test materials by conducting plant and animal metabolism studies and by assessing toxicity of the metabolites/degradation products. 

Petrovic, M., Gehringer, P., Eschweiler, H., Barcelo, D. (2004). LC-MS-MS determination of oxidative degradation products of nonylphenol ethoxylates, carboxylates and nonylphenols in water. Water Sci. Technol. 50 (5), (Assessment and Control of Hazardous Substances in Water), 227-234. 

In the common vernacular, the terms specificity and selectivity are often interchangeably used. More properly, a method is said to be specific if it provides a response for only a single analyte, while the term selective means that the method provides responses for a number of chemical entities that may be distinguished from each other. Selectivity also implies the ability to separate the analyte from degradation products, metabolites, and coadministrated drugs [12]. USP 28 [1] defines specificity as the ability to assess the analyte unequivocally in the presence of other components such as impurities, degradation products, and the matrix. IUPAC and AOAC have preferred the use of the term selectivity than specificity for methods that are completely selective, while USP, ICH, and FDA used the term specificity . Due to the very number of limited methods that respond to only one analyte, the term selectivity is usually more suitable, and this usage will be used in this work. 

A major area for research includes further establishing key biomarkers of exposure. Because each agent may have multiple metabolites, degradation products, protein or DNA adducts, there are many potential biomarkers. Establishing which are most suitable depends on multiple factors including cost, the analytical standards required, and laboratory expertise. The methodology for assessing each biomarker would then have to be validated and a QC system put in place. 

Improved risk assessment methodologies regarding surfactants and their degradation products. 

Surfactants and their biotransformation products enter surface waters primarily through discharges from wastewater treatment plants (WWTPs). Depending on their physicochemical properties, surface-active substances may partition between the dissolved phase and the solid phase through adsorption onto suspended particles and sediments [1,2]. Several environmental studies have been dedicated to the assessment of the contribution of surfactant residues in effluents to the total load of surfactants in receiving waters. This contribution reviews the relevant literature describing the presence of linear alkylbenzene sulfonates (LASs) and in particular of their degradation products in surface waters and sediments (Table 6.3.1). 

However, although degradation is known to occur under both aerobic and anaerobic conditions, data are not available on the identity of degradation products. Because the limited studies on the mechanisms of injury from di-ra-octylphthalate suggest that mono-n-octylphthalate is the proximate toxicant, it is important to know whether the reduction of di- -octylphthalate is coupled with the accumulation of mono- -octylphthalate. The environmental fate of di-n-octylphthalate and its metabolites is not sufficiently understood to allow assessments of its exposure potential to be made. Additional data are needed on the... 

Agut et al. (2011) assessed the different technology transfer options and reported that within Sanofi-Aventis that option 1 (comparative testing) is the approach of choice for critical methodologies, i.e. assay, degradation products, and in some cases water content and dissolution. Option 2 (co-validation) is reserved for less-critical methodologies, i.e. residual solvents by gas chromatography (GC), water content, dissolution and particle size methods whereas, option 4 (transfer waiver) is restricted to pharmacopoeial compendial methods, i.e. appearance, pH, particulate matter, etc. 

Methods for Determining Parent Compound and Degradation Products in Environmental Media. While analytical methods appear to be available for the analysis of 1,2-diphenylhydrazine, no methods were found for the preservation of 1,2-diphenylhydrazine in ambient air, water, or soil samples. Such methods would allow the development and analysis of a monitoring program designed to better assess the concentrations of 1,2-diphenylhydrazine in and around hazardous waste sites. 

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