Sequential electrochemical treatment

Yu J, Kupferle MJ (2008) Two-stage sequential electrochemical treatment of nitrate brine wastes. Water Air Soil Pollut Focus 8 379-385... 

In the second instance, the electrochem-ically generated bromoquinone monoketal (90) was converted to the organolithium reagent (91) (Scheme 21) [46, 47]. Its reaction with ketal (92), a synthon for the 1,4-dipole (93) [49, 50], proceeded smoothly to afford, after sequential treatment with aqueous acid and boron tribromide, a 60% yield of a-dtromydnone (94). 

Precolumn derivatization methods include 1,2-diphenylethylenediamine treatment, dansylation of E, NE and DA, derivatization of NE and DA by o-phthalaldehyde and mercaptoethanol and derivatization of catecholamines with 9-fluorenylmethyloxycarbonyl chloride (FMOC-Cl). Derivatization with o-phthalaldehyde increases the sensitivity of NE and DA, but E is not measured because only primary amines are derivatized. Co-analysis of catecholamines, metanephrines and other related compounds by combined electrochemical oxidation and fluorescence derivatization had also been reported. ° This approach involves sequential chromatographic separation, coulometric oxidation and final chemical derivatization with 1,2-diphenylethylenediamine to fluorescent products. 

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