Stable solution of stannous and a colour strip method for stannous estimation

At present no method for routine estimation of stannous is available and one has to depend entirely on the initial quantity of stannous compound taken which usually has significant fraction of the oxidised form-stannic. In the present study we have firstly achieved a nearly stable solution of stannous chloride and then developed a dip strip method for quick estimation of Sn++ concentration by noticing the color developed. The basis of color formation is the reaction between stannous and phosphomolybdate to give blue color. Two types of strips have been used; one the phosphomolybdate strips for Sn++ concentration up to 0.5 mg/ml and the other yellow strip for higher concentration of 50-100 ug/ml of Sn++, and color sensitivity is 100 ug. For accurate measurements, a spectrophotometric method of optical density measurement of the color in liquid media at 700 nm has been standardised. The color strip method is very simple and practical method and shall be useful in routine radiopharmacy work