Cobalt-ammonium pyrrolidine copper determination

Cabezon et al. [662] simultaneously separated copper, cadmium, and cobalt from seawater by coflotation with octadecylamine and ferric hydroxide as collectors prior to analysis of these elements by flame atomic absorption spectrometry. The substrates were dissolved in an acidified mixture of ethanol, water, and methyl isobutyl ketone to increase the sensitivity of the determination of these elements by flame atomic absorption spectrophotometry. The results were compared with those of the usual ammonium pyrrolidine dithiocarbamate/methyl isobutyl ketone extraction method. While the mean recoveries were lower, they were nevertheless considered satisfactory. 

Jin [666] used ammonium pyrrolidine dithiocarbamate and electrothermal atomic absorption spectrometry to determine lead, cadmium, copper, cobalt, tin, and molybdenum in seawater. 

APHA. 1985f. Determination of low concentrations of cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, silver, and zinc by chelation with ammonium pyrrolidine dithiocarbamate (APDC) and extraction into methyl isobutyl ketone (MIBK)-method 303B. In Standard methods for the examination of water and wastewater. 16th ed. Washington, DC American Public Health Association, 160-162. 

Several methods have been reported for concentrating lead, cobalt, and nickel in blood, urine, brines, and water prior to final determination by atomic absorption. Sprague and Slavin (6) described a procedure for determining these elements plus copper, cadmium, iron, and manganese in concentrated potassium chloride solutions. The metals were chelated with ammonium pyrrolidine dithiocarbamate (APDC) and extracted with methyl isobutyl ketone (MIBK). It was reported that the optimum pH for the extraction was approximately 2.8. Berman (J) described a similar chelation-extraction procedure for determining lead in urine and blood. Burrell (2) developed a procedure for determining cobalt and nickel in natural waters by atomic absorption in which both metals are first coprecipitated with ferric chloride from ten liters of water. The separated precipitate is subsequently dissolved and made up to 100 ml. volume with hydrochloric acid and water so that the final pH of the solution is 2.5. The nickel and cobalt are then chelated with APDC and extracted with three 10 ml. volumes of MIBK. Three extractions are necessary to achieve complete recovery of the chelated cations. A detection limit of 0.3 fig. of nickel per liter and 0.15 fig. of cobalt per liter was found. 

Berndt et al. [740] have shown that traces of bismuth, cadmium, copper, cobalt, indium, nickel, lead, thallium, and zinc could be separated from samples of seawater, mineral water, and drinking water by complexation with the ammonium salt of pyrrolidine- 1-dithiocarboxylic acid, followed by filtration through a filter covered with a layer of active carbon. Sample volumes could range from 100 ml to 10 litres. The elements were dissolved in nitric acid and then determined by atomic absorption or inductively coupled plasma optical emission spectrometry. 

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