Degradants screening

Table 7.1.2 MS settings for pyrimidine degradation screening in the positive ESI mode ... 

Design procedures included laboratory tests on polymer rheology, relative permeability, shear degradation, screen factor, stability, and salinity effects. Computer simulations were performed to predict recoveries and to examine optimum polymer concentration. Field injectivity tests were conducted to examine injectivity behavior with time and to gain experience in surface handling of the polymer. Pressure-falloff tests were conducted in conjunction wiA the injectivity tests. Finally, the prqiamtion involved design of the polymer-injection plant and analysis of costs. 

In plant maintenance, the availability of quantitative and non-invasive screening NDT methods will reduce the time needed for shutdowns and increase the intervals between them. Modem NDT methods will become just as important a tool for Risk Based Inspection approaches and maintenance planning as operational parameters and degradation mechanisms already are. 

In general, stabilizers function by reaction with proplnt decompn products. A number of methods have been described and a preliminary evaluation of these methods was conducted by several labs under a cooperative program. Based on results from these screening tests, the PicArsn spec tropho tome trie methods for available stabilizer and primary degradation products were selected for further study. The initial phase of this program was an attempt to standardize the necessary spectrophotometric factors. Significant differences with regard to the factors obtained... 

In the modified OECD Screening Test (OECD 301E), which indicates complete degradation or elimination according to the German Chemical Substances Control Act, alkanesulfonates are biodegradable to 95% (decrease in DOC, the dissolved organic carbon). 

Figure 3.30 TIC trace obtained from the LC-MS analysis of atrazine and its degradation products. Reprinted from J. Chromatogr., A, 915, Steen, R. 1. C. A., Bobeldijk, I. and Brinkman, U. A. Th., Screening for transformation products of pesticides using tandem mass spectrometric scan modes , 129-137, Copyright (2001), with permission from Elsevier Science.

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. 

Rott B, Viswanathan R, Freitage D, et al. 1982. Comparison of the applicability of various tests for screening the degradability of environmental chemicals. Chemosphere 11 1-10. 

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