本文报导了在阳离子表面活性剂CTAB存在下,用二甲基苯胺兰(Ⅱ)光度法测定镁的新方法的条件,方法的特点是灵敏、线性关系良好。有显著的增溶作用,可在10%的乙醇存在下测量吸光度,用铜试剂分离铁、铝、铜、锰等干扰元素,并用三乙醇胺掩蔽残余铁、铝元素,此法可用于球墨铸铁中小于0.1%镁量的测定。 This paper reports the new method for the determination of magnesium in the presence of cationic surfactant CTAB using dimethylanilinamine (Ⅱ) spectrophotometry. The method is characterized by its sensitivity and good linearity. Has a significant role in solubilization, absorbance can be measured in the presence of 10% ethanol, copper, iron, aluminum, copper, manganese and other interference elements, and triethanolamine masking the residual iron, aluminum, this method can be used in ductile iron small Determination of the amount of 0.1% magnesium.