COMPLEXATION BEHAVIOR OF TIN(II) ION WITH DERIVATIVE OF P-AMINOHIPPURIC ACID

Complex formation between tin(II) ion and -(biscarboxymethyl)-aminomet hyl-carbamino-hippuric acid (PAHIDA) in 0.5 M NaClO4 ionic medium at 2 98 K, was studied by means of u.v. spectrophotometry and glass electro de potentiometric titrations. In the concentration range 0.09 less tha n or equal to [Sn] less than or equal to 0.150, 0.5 less than or equal to [PAHIDA] less than or equal to 3.0 (mmol dm(-3)) and 1.30 less tha n or equal to pH less than or equal to 6.5, mathematical analysis of p otentiometric data, with the aid of general least-squares programme Su perquad, indicates the formation of the following complexes and their respective stability constants (log (beta +/- sigma)): [Sn(H(2)PAHIDA) ] (12.98 +/- 0.15), [Sn(HPAHIDA)] (9.38 +/- 0.05), [Sn(PAHIDA)] (5.74 +/- 0.01) and [Sn(OH)PAHIDA] (1.55 +/- 0.09) as well as several pure h ydrolytic complexes of tin(II). The effect of tin(II)-PAHIDA complexat ion on labelling yield of PAHIDA with (TcO4-)-Tc-99m was investigated. The optimum yield (90%) was achieved at PAHIDA to tin(II) concentrati on ratio 30:1 and pH = 5.5.