摘要:
通过循环伏安法探讨银电极在氯离子测试液中电化学反应机理,以此为基础建立一种快速检测生乳中氯离子的电化学方法。结果表明,银电极在氯离子测试液中正向扫描时,银失去电子氧化成银离子,然后与溶液中的氯离子结合生成氯化银沉淀;而负向扫描时,氯化银还原为银。在生乳中掺盐后,用10%的三氯乙酸溶解生乳样品,通过离心除去蛋白质和脂肪,加入1 mol/L Na2SO4,得到提取液,经检测提取液可知,银电极产生一对氧化还原峰,且峰电流与生乳中氯离子浓度在0.03~0.21 mol/L范围内呈线性关系。此方法检出限为0.001 mol/L,回收率和相对标准偏差分别在93.3%~113.7%和2.33%~4.89%,与GB5009.44-2016银量法比较无明显差异。此法样品预处理简单、测定速度快、成本低,能较好的运用于实际生产线。
关键词:
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电化学方法
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氯离子
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生乳
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检测
Abstract:
Electrochemical reaction mechanism of silver electrode in chlorine ion test solution was discussed by cyclic voltammetry, and based on this, an electrochemical method for rapidly detecting chloride ions in raw milk was established. The results showed that when the silver electrode in the chloride ion test solution was positively scanned, silver oxidized to silver ions due to lose an electron, then combined with chloride ions in solution to form silver chloride precipitate. When the silver electrode was negatively scanned, silver chloride was reduced to silver. After the salt was mixed in the raw milk, the raw milk sample was dissolved with 10% trichloroacetic acid, and the protein and fat in sample were removed by centrifugation, then 1 mol/L Na2SO4 was added to the centrifugal liquid to obtain an extract solution. After detecting the extract, it could be seen that the silver electrode produced a pair of redox peaks, and the peak current was linear with the concentration of chloride ions in the raw milk in the range of 0.03~0.21 mol/L. The detection limit of this method was 0.001 mol/L, and the recovery and relative standard deviation were 93.3%~113.7% and 2.33%~4.89%, respectively. There was no significant difference compared with GB5009.44-2016.The method had simple pretreatment, fast measurement and low cost, and could be applied to the actual production line.
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