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为检测松花蛋中的铅含量,我们拟定了2.0×10~(-2)柠檬酸—2.5×10~(-3)M四乙基碘化铵体系,在pH1.0底液条件下以示波极谱法测定pb~(2+)”,获得满意效果。一、主要仪器和试剂:仪器为JP～IA型示波仪(三电极),试剂为铅标准溶液,系用纯金属铅配成1mg/mI的pb~(2+)标准溶液,用时稀释至所需浓度;此外有混合底液,为配制的0.2M柠檬酸—0.025M四乙基碘化铵水溶液,贮于棕色瓶中;其它如硝酸、高氯酸及盐酸,均为分析纯,实验用水为去离子水。二、分析步骤:准确吸取适量样品溶液于小烧杯中,加入混合底液5ml,加去离子水20m1,调节溶液的pH值为1.0,转移到50m1容量瓶中定容、摇匀,再倒入电解槽中,于原点电位—0.7V处倒数作图,在—0.81V处记录铅的峰电流。三、结果和讨论: 1.底液条件的选择:固定pb~2’的浓度为0.1m
In order to detect the content of lead in the egg, we developed a 2.0 × 10 ~ (-2) citric acid-2.5 × 10 ~ (-3) M tetraethylammonium iodide system, Polarographic determination of pb ~ (2) ", to obtain satisfactory results. First, the main instruments and reagents: instrument for the JP ~ IA oscilloscope (three electrodes), reagents for the lead standard solution, Department of pure metal lead Into 1mg / mI of pb ~ (2+) standard solution, dilute with time to the desired concentration; in addition to a mixed base solution, formulated 0.2M citric acid - 0.025M tetraethylammonium iodide aqueous solution, stored in a brown bottle ; Other such as nitric acid, perchloric acid and hydrochloric acid, are of analytical grade, the experimental water is deionized water. 二, Analysis steps: Accurately draw the right amount of sample solution in a small beaker, add mixed base solution 5ml, add deionized water 20ml, Adjust the pH value of the solution to 1.0, transfer to a 50 ml volumetric flask, dilute to volume, shake well, then pour into the cell, plot the reciprocal at the origin potential of -0.7 V and record the peak current of lead at -0.81 V. Tri Results and discussion: 1. The choice of bottom liquid conditions: the concentration of fixed pb ~ 2 ’0.1m