分光光度法测定豆浆中的铝含量

The Determination of the Content of Aluminum in Soya-bean Milk by Spectrophotometry

用分光光度法测定了豆浆中的铝含量．利用高温灰化法对样品进行前处理，Al^3＋在乙酸-乙酸钠缓冲介质中与络天青S及十六烷基溴化铵反应形成蓝绿色的三元络合物．在波长620nm处有最大吸光度，其回归方程为Y=O．10078X-0．00653，相关系数r为0．99912，测量7次，摩尔吸光系数SD为0．0095，k为1．8187×10^4 L／mol·cm，检出限m为0．004709gg，铝含量在0．00～0．610μg／lnL范围内与吸光度值呈良好的线性关系．样品1的回收率为97．28％～99．53％，样品2回收率为94．43％～97．81％，样品加标回收率比较理想，远远低于规定标准，故可以放心饮用豆浆．

The content of aluminum in Soya-bean milk is determined by Spectrophotometry. The sample is pro-processed by high temperature ashing method, and in the buffer medium of acetic acid-sodium acetate, the trivalent aluminium ion reacts with CAS to form a blue ternary complex. The maximum absorbance appears at the wavelength of 620 nm. The regression equation is Y=0.10078X-0.00653, the correlation coefficient r is 0.99912. The molar absorption coefficient SD is 0.0095 after seven times of measuring and k=1.8187×10^4L/mol.cm, detection limit m=0.004709μg. In the range of 0.00-0.610 μ/mL, there is a linear relation between the content of aluminum and absorbance. The recovery of sample is good. The recovery of sample one is 97.28%～99.53%, and the recovery of sample two is 94.43%～97.81%. It shows that the recovery is far below the standard, so you can rest assured to drink soya-bean milk, and the method is worth popularizing in food daily supervision.