HCB

Figure 15.1 Separation of pesticides from butter by using LC-GC-ECD. Peak identification is as follows 1, HCB 2, lindane 5, aldrin 7, o,p -DDE 10, endrin 11, o,p -DDT 13, p,p -DDT peaks 3, 4, 6, 8, 9, 12, 14, 15 and 16 were not identified. Adapted from Journal of High Resolution Chromatography, 13, R. Barcarolo, Coupled EC-GC a new method for the on-line analysis of organchlorine pesticide residues in fat , pp. 465-469, 1990, with permission from Wiley-VCH.

Working with rats, Lntz et al. (1977) compared the rates of loss from blood of 4,-CB (rapidly metabolized) with that of 2,2, 4,4, 5 -HCB (slowly metabolized). Both showed biphasic elimination, with the former disappearing much more rapidly than the latter. Estimations were made of the rates of hepatic metabolism in vitro, which were then incorporated into toxicokinetic models to predict rates of loss. The predictions for HCB were very close to actual rates of loss for the entire period of... 

Looking at the foregoing results overall, the rates of loss in vivo are related to the rates of metabolism in vitro, measured or estimated. As with the OC insecticides, problems of persistence are associated with compounds that are not readily metabolized, for example, 2,2, 4,4, 5,5 -HCB in the foregoing examples. For further discussion of the dependence of elimination of lipophilic xenobiotics on metabolism, see Walker (1981). 

In forced-convective boiling the effective heat-transfer coefficient hcb can be considered to be made up of convective and nucleate boiling components h fc and h nb. 

All the major human liver CYPs are available as HCBs, allowing each human CYP enzyme to be screened in parallel to determine which one is the active enzyme for metabolism of a given drug. Once identified, the most active human CYP can be scaled up and used to produce larger quantities of the desired metabolite. 

Some examples are illustrative of the use of the use of HCBs for metabolite synthesis. Table 9.4 shows the reaction of various HCBs for the production of metabolites. Reactions are typically complete within 4 h. In the examples shown, conversions range from 70 to 100% in... 

Petrick et al. [375] extracted up to 2000 dm3 of Atlantic Ocean waters using various solid resins. Down to 5 ng/dm were determined of chlorinated biphenyls, HCB, DDE, and polyaromatic hydrocarbons in samples taken at depths down to 4000 metres. 

JT-60U Japan Dunlop DMS704 Hitachi HCB-18S Ibiden ETP-10 Showa-Dcnko CC312... 

---