Demeter

Employing demetalization technology to remove metals from the equilibrium catalyst... 

Both demetalization and passivation technology are addressed in Chapter 3. 

Using demetalizing technology to remove the metals from the catalyst... 

The MagnaCat separation process (demetalizing technology), which allows discarding the older catalyst particles containing higher metal levels... 

A third access to isocorroles was found7 when a tetrapyrrole 11 having an acrylaldehyde side chain was cyclized in presence of copper(II) or cobalt(II) salts. In this case isocorrole-9-carb-aldehydes 12 are formed with copper and cobalt in the oxidation state + III. The copper compound can easily be demetaled by hydrochloric acid to yield the metal-free isocorrole. In contrast, the cyclization of the tetrapyrrole in the presence of palladium(II) gives the isopor-phycene (see Section 1.7.1.). 

Exposure Levels in Humans. Endosulfan and endosulfan sulfate can be measured in human blood, urine, and tissues following exposure to high levels in worlq)lace environments or following accidental or intentional ingestion of insechcides containing endosulfan (Coutselinis et al. 1978 Demeter and Heyndrickx 1978 Demeter et al. 1977). However, no monitoring studies are available in which human... 

The method of choice for the determination of a- and P-endosulfan in blood, urine, liver, kidney, brain, and adipose tissue is gas chromatography equipped with an electron capture detector (GC/ECD) (Coutselinis et al. 1976 Demeter and Heyndrickx 1979 Demeter et al. 1977 Le Bel and Williams 1986). This is because GC/ECD is relatively inexpensive, simple to operate, and offers a high sensitivity for halogens (Griffith and Blanke 1974). After fractionation of adipose tissue extracts using gel permeation chromatography, detection limits of low-ppb (1.2 ng/g) were achieved for endosulfan and other chlorinated pesticides using GC/ECD (Le Bel and Williams 1986). 

GC/MS has been employed by Demeter et al. (1978) to quantitatively detect low-ppb levels of a- and P-endosulfan in human serum, urine, and liver. This technique could not separate a- and P-isomers, and limited sensitivity confined its use to toxicological analysis following exposures to high levels of endosulfan. More recently, Le Bel and Williams (1986) and Williams et al. (1988) employed GC/MS to confirm qualitatively the presence of a-endosulfan in adipose tissue previously analyzed quantitatively by GC/ECD. These studies indicate that GC/MS is not as sensitive as GC/ECD. Mariani et al. (1995) have used GC in conjunction with negative ion chemical ionization mass spectrometry to determine alpha- and beta-endosulfan in plasma and brain samples with limits of detection reported to be 5 ppb in each matrix. Details of commonly used analytical methods for several types of biological media are presented in Table 6-1. 

Liver Addition of water to sample followed by homogenization extraction with benzene, clean-up on silica column and HPLC GC/ECD No data No data Demeter and Heyndrickx 1979... 

Liver Addition of water to sample followed by homogenization an dextraction with benzene cleanup extract on HPLC GC/MS Low jug/L (ppb) levels No data Demeter etal. 1978... 

Methods for Determining Biomarkers of Exposure and Effect. GC/ECD, GC/MS, and GC/MC are analytical techniques used for measuring endosulfan in blood, urine, hand rinses, and various biological tissues and excreta at low- and sub-ppb levels (Coutselinis et al. 1976 Demeter and Heyndrickx 1978 Demeter et al. 1977 Griffith and Blanke 1974 Guardino et al. 1996 Kazen et al. 

Demeter J, Heyndrickx A. 1978. Two lethal endosulfan poisonings in man. J Anal Toxicol 2 68-74. 

Demeter J, Heyndrickx A. 1979. Selection of a high-performance liquid chromatographic cleanup procedure for the determination of organochlorine pesticides in fatty biological extracts. Vet Hum Toxicol 21 151-155. 

Demeter J, Heyndrickx A, Timperman J, et al. 1977. Toxicological analysis in a case of endosulfan suicide. Bull Environ Contam Toxicol 18 110-114. 

Elvin, F. J., and Pavel, S. K., Commercial Operations of a Demet Unit, in NPRA Annual Meeting. 1993. San Antonio, TX, March 21-23. AM-93-54. 

Love RR, Newcomb PA, Wiebe DA, Surawicz TS, Jordan VC, Carbone PP, DeMets DL (1990) Effects of tamoxifen therapy on lipid and lipoprotein levels in postmenopausal patients with node-negative breast cancer. J Natl Cancer Inst 82 1327-1332... 

DEMET (2) A process for removing metal contaminants from spent FCC catalysts by a series of pyrometallurgical and hydrometallurgical procedures. These typicaly include calcination, chlorination, and sulfiding. The demetallized catalyst can be re-used. Developed by ChemCat Corporation, LA, in 1988 first operated commercially in New Jersey in 1989. Now operated by Coastal Catalyst Technology. 

Druzhinin SI, Kovalenko SA, Senyushkina TA, Demeter A, Januskevicius R, Mayer P, Stalke D, Machinek R, Zachariasse KA (2009) Intramolecular charge transfer with 4-fluorofluorazene and the flexible 4-fluoro-N-phenylpyrrole. J Phys Chem A 113 9304-20... 

DeMets DL, Furgerg CD, Friedman LM, eds. Data Monitoring in Clinical Trials A Case Studies Approach, Springer, New York, 2006. 

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