Question

To prepare standard streptomycin solution in estimation streptomycin by sodium
nitroprusside method, streptomycin solution containing 1000 ug/ml should be diluted
by
(A) adding 50 ml streptomycin solution in 50 ml distilled water.
(B) adding 10 ml streptomycin solution in 90 ml distilled water.
(C) adding 20 ml streptomycin solution in 80 ml distilled water.
(D) adding 10 ml streptomycin solution in 100 ml distilled water.
(E) adding 20 ml streptomycin solution in 100 ml distilled water.​

Answer 1

Explanation:

rapid and simple spectrophotometric method for the determination of streptomycin has been developed and validated. The method was based on the reaction of streptomycin with sodium nitroprusside in the alkaline medium forming a red product measured at the maximum absorption of 495 nm. The stoichiometric ratio of the product is 1:1. Beer's law is obeyed in a range of 1.87 µg mL−1 ∼ 279.8 µg mL−1 of streptomycin and ∊495 is 6.0 × 103 L·mol−1 cm−1.Under the optimum condition, the equation of linear regression is A = 0.00742 + 0.05683 C (× 105 mol·L−1), with a linear correlation coefficient of 0.9990. The detection limit (3σ/k) is 0.96 µg mL−1, the relative standard deviation (RSD) is 2.40%, and the average recovery rate is 98.3%–102.7%. Every parameter has been optimized, and the reaction mechanism has been studied. The proposed method has been successfully applied to the determination of streptomycin for injections and tablets of pharmaceutical preparation. Analytical results obtained by this new method were very gratifying.