A simple, rapid method for the determination of the benzodiazepines, diazepam and chlordiazepoxide, and their metabolites by high performance liquid chromatography (HPLC) has been developed. The procedure is applicable to the assay of other similar drugs in biological fluids. The method utilizes BondElut extraction columns to facilitate the extraction. BondElut columns selectively adsorb the benzodiazepines and metabolites from serum at a pH of 9.0. The compounds are eluted with 300 microliters of methanol which makes sample concentration rapid, if even necessary. Analysis is performed using isocratic reversed-phase chromatography, and quantitation is carried out by ultraviolet (UV) detection. Using this procedure, it is possible to determine drug and metabolite levels to as low as 25 ng/ml in 0.5 ml of serum.
The methods described for the wet oxidation of beer, wort, malt, barley, barley flakes, malt combings, hops, pressed and dried yeast, isinglass, and coal have proved satisfactory and time‐saving over a number of years. They involve digestion with nitric and sulphuric adds under conditions which preclude loss of the metal sought (Zn, Pb, Cu, Fe, Mn, Ni, As), and are at the same time simple and safe in execution and economical of reagents.
Nickel is determined in the sulphuric acid residue remaining after the wet oxidation of a beer or brewing material. α‐furildioxime is added, and the resulting complex is extracted with chloroform. Any copper present is removed by shaking the extract with dilute sulphuric acid, and the yellow colour of the complex is measured photometrically.
Copper is determined in the residue obtained after wet oxidation of beer or brewing materials as described in a previous paper (this Journal, 1951, 363). When the residue is treated with sodium diethyldithiocarbamate, a compound is formed which is soluble in carbon tetrachloride giving a yellow solution. The yellow colour of this solution may be matched by glass slides in a Lovibond tintometer or evaluated in a photoelectric colorimeter. The copper is determined by reference to standard curves.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.