Extraction spectrophotometric determination of maneb with 1-(2'-pyridylazo)-2-naphthol (PAN).
A rapid, sensitive, simple and selective spectrophotometric method has been developed for the determination of micro-quantities of maneb (manganese ethylenebisdithiocarbamate) after extraction of the manganese-PAN complex in isobutyl methyl ketone (MIBK). The complex absorbs strongly at 550 nm. Beer's law is obeyed over the concentration range 0.37-3.75 microg/ml. The molar absorptivity was found to be 4.1 x 10(4) l. mole(-1) . cm(-1). The developed method has been applied to the determination of maneb in commercial formulations, synthetic mixtures, grain and in the presence of various other dithiocarbamates.
Determination of manganese in high-purity niobium, tantalum, molybdenum and tungsten metals with pan.
A spectrophotometric method for the determination of 0.0005-0.10% of manganese in high-purity niobium, tantalum, molybdenum and tungsten metals is described. The matrix materials are separated from the manganese by extraction as cupferrates, after sample dissolution, then the red complex formed between manganese(II) and 1-(2-pyridylazo)-2-naphthol, PAN, is extracted into chloroform from an ammoniacal tartrate-cyanide medium. The absorbance of the extract is determined at 562 mmicro. With the exception of zinc and lead, other impurities present in the four high-purity metals described do not interfere with the proposed method.
Determination of copper in high-purity niobium, tantalum, molybdenum and tungsten metals with bathocuproïne
Abstract A spectrophotometric method for determining 0.0005–0.125% of copper in high-purity niobium, tantalum, molybdenum and tungsten metals is described. After sample dissolution and reduction of copper to the univalent state with ascorbic acid, the yellow complex formed by copper I and bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) is extracted into n-amyl alcohol and the absorbance of the resulting extract is determined at 476 mμ. Other impurities present in the four high-purity metals described do not interfere in the proposed method.