Degradation acid residence time

One of the most intensively examined type of pesticides handled under PBl conditions were the chlorinated phenoxy acids and their esters which were determined in water [82-86] and soil samples [83, 86]. Even results of an interlaboratory comparison study of 10 chlorinated phenoxy acids using PBl or TSP ionisation were published by Jones et al. [37] [87]. Statistically significant differences were observed between the interfaces and under these conditions PBl was found to have a better precision than TSP [87]. Betowsld et al. [88] observed thermal degradation induced by residence time in the ion source and the influence of ion source temperature in the ionisation of the chlorinated phenoxy acid derivatives 2,4-D and MCPA. Several authors successfully examined a large number of different carbamate pesticides [67, 89, 90] and their transformation products by PBl-LC-MS [89, 90], by PBl-FIA-MS (flow injection analysis) [67] or by supercritical fluid chromatography (SEC) PBl-interfaced to MS [91],... 

During an investigation of the thermal degradation of poly(vinylchloride - vinylacetate) blends, McNeill (14) observed acetyl chloride in the degradation products. We investigated this aspect by FTIR-EGA and found that the amount of acetyl chloride in the effluent decreased with increased residence time in the hot zone. This suggested that acetyl chloride is a primary decomposition product, rather than a product of reaction between HCl and acetic acid from pyrolysis of the copolymer. McNeill s work was performed by thermal volatilisation analysis and did not provide on-the-fly identification of the pyrolysis products. 

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