Test Methods for Potassium Content in Compound Fertilizer

With 404.4 nm as measured wavelength we researched the methods determining the potassium content in compound fertilizer with flame atomic absorption spectrometry through adding quantitative cesium chloride into test liquid.The 1∶6 fuel to air ratio,8 mm height combustor,3.51 mA current for hollow cathode lamp of potassium are optimum conditions.There are good linear relation between potassium concentration and absorbance when the concentration is at 0～80 μg/mL.While determined standard deviation below 0.05%,the relative standard deviation lowers 1.0%,recovering rate of standard sample is at 98.0%～102.0%.The result obtained by this method is basically in accordance with the one obtained by gravimetric method.The method is suited for examining large amount of samples.