1978 Volume 27 Issue 11 Pages 680-683
4-Capryl-3-methyl-1-phenyl-5-pyrazolone (CMPP) forms extractable chelates with many metals and is very stable in acid or ammoniacal solution compared with other similar reagents. A method is described for the determination of a micro amount of lead, using atomic absorption spectrophotometry in conjunction with solvent extraction technique. The effect of pH, amount of CMPP, diverse ions in the aqueous phase and shaking time on the extraction of lead were examined. Less than 250 μg of lead was quantitatively extracted into 5 ml of 0.3% (w/v) CMPP-MIBK solution from an aqueous solution at pH 10, by shaking for 5 min, and then the absorbance was measured with an atomic absorption spectrophotometer. More than 10 μg of Fe3+ caused a negative error, but 10 mg of Cd2+, Ni2+, 0.3 g of Zn2+, 1 g of Cu2+ did not interfere. The present method was applied to the determination of a micro amount of lead in high-purity zinc and copper. Copper {(1020)g} and zinc {(46)g} samples were dissolved in HNO3 and HCl by heating. When extracting lead, the sample solution was adjusted to pH 10 with ammonium hydroxide, because these matrices could be masked as copper or zinc ammine complex. The analytical results by the proposed method almost agreed with the values obtained by emission spectrophotometric method or spectrophotometric method.
