分光光度法测定饲料中铵盐的含量

Determination of ammonium salt in feed by spectrophotometry

目的建立一种用纳氏试剂分光光度法测定饲料中铵盐含量的检测方法。方法在碱性溶液中,加热蒸馏使样品中的氨游离出来,用盐酸溶液吸收,碘离子和汞离子在此条件下,会与氨反应生成红棕色络合物,此物质在波长400 nm左右会有强烈的吸收。而吸光度在一定浓度范围内与样品溶液中氨含量成正比,从而计算样品中铵盐的含量。结果该方法中铵盐浓度在0~2.0μg/mL范围内,其吸光度和浓度呈良好的线性关系r^2>0.999,平均回收率达到90%~110%之间。结论该方法操作简单快捷,稳定性好,可用于饲料中铵盐的测定。

Objective To establish a method for the determination of the ammonium salt in feed by spectrophotometry using the Nnessler reagent.Methods The sample was placed in alkali solution,after heating up and,the solution was distilled so that ammonium was freed out of the sample.The freed ammonium was absorbed using hydrochloride solution.In such solution,iodide ions and mercury ions reacted with ammonium to produce reddish brown complex compound that absorbed lights powerfully with wavelengths around 400 nm.The absorbance was directly proportional to the ammonia content in the sample solution within a certain concentration range,so the content of ammonium salt in the sample could be calculated.Results The ammonium concentration of 0-2.0μg/mL supported a perfect linear relationship(r^2>0.999)between the light absorbance and the ammonium concentration,ensuring a recovery rate at 90%-110%.Conclusion This method is simple,fast and stable,and can be used for the determination of ammonium salt in feed.