【摘要】 采用紫外吸光光度法测定蔬菜鲜样中硝酸盐含量,该法适用于不同硝酸盐含量的蔬菜样品测定,与传统的酚二磺酸法相比,该法精密度和准确度高、操作简便,具有较大的推广价值。更多还原

【Abstract】 Based on its characteristic absorption at 220nm, nitrates in fresh vegetables were determined by UV-spectrophotometry. Nitrates in the sample were extracted into an ammoniacal buffer at pH 9.6～9.7. By adding some activated charcoal to the buffer solution the pigments were removed simultaneously. The protein was removed by adding potassium ferrocyanide and zinc sulfate as precipitant. The interference of nitrite was eliminated by addition of sulfamic acid before the absorption measurement. This method has the special features of high accuracy and precision, and more convenient in operation. In comparison with the conventional phenol disulfonic acid method, no significant difference was found.更多还原