Satori Utsumi

Atomic Absorption Spectrophotometric Determination of Ultramicro Amount of Cadmium by Extraction of Cadmium lodide-Zephiramine lon-pair

A new determination method of cadmium by atomic absorption speetrophotometry was proposed.The methQd was based Qn the extraction Qf th ion-pair, fQr, 4 bet we anion of cadmium iodide eomplex and zephiramine cation, with ethyl acetate. The cadmium concentration in the ethyl acetate was determined by atomic abserption spectrophotometry by the use of airacetylene flame.To 50 ml of an aqueous sample solution in a saparatpry funnel weiie added l ml of 2 molll potassium iodide solution, l ml of the acetate buffer solutien (pH 4.6) and 10 ml of ethyl acetate. The mixture was shaken for 2 rninutes in order to extract the cadmium-iodidezephiramine ion pair into ethyl acetate.After separating organic phase the absorbsnce was measured with air-acetylene flatme at 2288 A cadmium-line.By this method, the cencentration range frem 2 to 40 ppb of cadmium in the aqueous sample solution could be determined accurately. The standard deviation was O.0025 and the variation coeMcient was O.98%e at the cadmium level of 30 ppb, Copper interfered seriously with the determination of cadmium, but the considerabiy large amounts of many ether popular eations and anions did not interfere. The interference due to copper could be removed by masking it with thiourea, This method was applied to the determinatien of cadmium in fresh water.