Zero, first and second order derivative spectrophotometric methods were developed for the determination of insulin. The standard solutions and pharmaceutical sample were prepared in 0.01 M HCl. Absorbences of insulin were measured at 276 nm for the zero order by measuring height of peak from zero, at 264, 277 and 284 nm for the first order and at 277, 280, 283 and 289 nm for second order deriva...