该研究建立了一种励磁等电势法测定食品中硫酸铝钾含量的分析方法。采用励磁等电势法，向初级线圈施加频率300~700 Hz及励磁电压5~20 V的正弦交流信号，分析次级线圈中不同质量分数的硫酸铝钾溶液电学特性。结果发现，相同质量分数的硫酸铝钾溶液中，励磁电压的变化对其体系各位点对地电压的影响大于频率的变化。当硫酸铝钾溶液质量分数增加时，随频率及励磁电压的增加，体系电势差增大，当励磁电压从5 V增加至20 V时，20 mg/kg硫酸铝钾溶液电势差提高78.79%。励磁等电势法中各参数呈线性相关，相关系数（r）为0.94，在300 Hz，20 V下检测4种市售粉丝产品，检测结果相对标准偏差均在1.50%以内，励磁等电势检测具有良好的重复性，且与化学法相比，检测结果相对误差在2.00%以内，励磁等电势法具有良好的准确性。励磁等电势法将粉丝的预处理料液作为次级线圈，测定其电学特性来量化硫酸铝钾含量，为食品中硫酸铝钾的检测提供了一种新方法。

Herein, an excitation equipotential method was established to determine the content of aluminum potassium sulfate in vermicelli. Sinusoidal AC signals with an excitation voltage of 5~20 V at 300~700 Hz were applied to a primary coil to analyze the electrical characteristics of aluminum potassium sulfate solution in a secondary coil (or sample coil). The impact of excitation voltages on ground voltages was greater than that of frequencies with the same mass fraction of aluminum potassium sulfate solutions. Increasing mass fractions of aluminum potassium sulfate solutions enhanced potential differences with increasing frequency and excitation voltage. On altering the excitation voltage from 5 V to 20 V, the potential difference of 20 mg/kg aluminum potassium sulfate solution increased by 78.79%. Parameters in the excitation equipotential method were linearly correlated, presenting a correlation coefficient (r) of 0.94. Four kinds of commercial vermicelli products were examined at 300 Hz and 20 V, and the relative standard deviations of detection results were within 1.50%. The excitation equipotential method exhibited repeatability. It also showed better accuracy than the chemical method, with relative errors for detection results within 2.00%. This excitation equipotential method helps analyze pretreated solutions of vermicelli at the secondary coil, determining its electrical characteristics to quantify the aluminum potassium sulfate content. This study provides a novel method for detecting aluminum potassium sulfate content in food.

中国博士后科学基金项目（2020M682725）；国家自然科学资金面上项目（32172353）；江苏省优秀青年基金项目（BK20211582）