Abstract
A simple and rapid photometric method for the determination of 0.0010.1% of tin in iron and steel with salicylideneamino-2-thiophenol (SATP) has been established. The tin (II)-SATP complex was formed in a lactic acid medium at the pH range from 1.8 to 2.2, and the absorbance obeyed Beer's law up to 70 μg of tin. The complex was stable for at least 5 hours. The established method was as follows.
A half gram of sample was decomposed in a mixture of hydrochloric acid and hydrogen peroxide (30%) and boiled for 23 minutes. After cooling, it was diluted with water and the interfering iron (III) was masked by 5 ml of L-ascorbic acid solution (10%).The pH of the solution was adjusted to 1.82.2 with sodium hydroxide solution (10%) by using 2, 4-dinitrophenol as an indicator. To it were added 2 ml of lactic acid (20%), 2 ml of sodium thiosulfate solution (1%) and 5 ml of SATP solution (0.1%). It was allows to stand for 5 minutes, and shaken for 1 minute with 10.0 ml of benzene. The absorbance was measured at approximately 415 mμ against benzene.
The proposed method was very sensitive and simple, and the time required for an analysis was about 28 minutes.
