I've prepared standard solution according to: 28 mg standard/100 ml. From this take out 1,0 ml and diluted to 100 ml
Test solution: 0,1 g test material/50 ml. Take out from this 10,00 ml and diluted to 50 ml.
To 10 ml standard and test material add 5,00–5,00 ml 8,5 m/V% NaOH. After this add 10,00-10,00 ml Sulfanilic acid and 10,00-10,00 ml 2 M HCl. and 10,00-10,00 ml naphtyl etilen diammin solution.
This was UV measuring method
Standard specific absorbance calc= absorbance*500/ weight in mg
Test specific absorbance calc= absorbance*12500 / weight in mg
Is this calculation OK?