二次导数极谱法测定工作液中2-乙基蒽醌和四氢-2-乙基蒽醌含量

Determination of EAQ and H_4EAQ Content in the Working Solution by Second Derivative Polarographic Method

建立了采用二次导数极谱法测定蒽醌法生产过氧化氢用钯催化剂选择性评价工作液中2-乙基蒽醌(EAQ)和四氢-2-乙基蒽醌(H4EAQ)含量的方法。克服了常规极谱法测定EAQ和H4EAQ含量时分辨率低、误差大等局限性,可使EAQ和H4EAQ的极谱波清晰地分离;并通过加入适量的除氧剂,有效消除了氧波对波形的干扰,改善了波形,并抑制了极谱极大峰的出现,实现了对工作液中EAQ和H4EAQ含量的准确测定。该法测定EAQ和H4EAQ的相对误差分别为+4.6%和+4.3%,相对标准偏差分别为2.1%和1.7%,检出限分别为4.1 mg/L和1.7 mg/L。

The determination method of EAQ and H4EAQ content in the working solution of palladium catalyst selective evaluation in the production of hydrogen peroxide by anthraquinone process through second derivative polarographic method is founded. It overcomes the defects of low distinguishablity and high error during determining the EAQ and H4EAQ content by general polarographic method, and clearly separates the polarographic wave of EAQ and H4EAQ. By adding proper deoxidant, it can effectively avoid the disturbance of oxygen wave, improve the waveform and inhibit the appearance ofpolarographic maximum peak, then realize the accurate determination of EAQ and H4EAQ content in working solution. During determining EAQ and H4EAQ content by this method, the relative errors are ＋4.6% and ＋4.3% respectively, the.relative standard deviations are 2.1% and 1.7% respectively, the detection limits are 4.1 mg/L and 1.7 mg/L respectively.