| 刘晓庚,吴李瑞,董思佳,杨奕明,刘季敏,胡妍君,张宇豪,秦怡航.基于高倍富集放大反应的双点电位滴定法测定谷物中氟含量[J].中国粮油学报,2020,35(5):181- |
| 基于高倍富集放大反应的双点电位滴定法测定谷物中氟含量 |
| Based on High Enrichment Amplification Reaction Double Point Potentiometric Titration for the Determination of Fluoride in Cereals |
| 投稿时间：2019-08-24 修订日期：2019-11-21 |
| DOI： |
| 中文关键词: 谷物 氟 含量 高倍富集放大反应 双点电位滴定法 |
| 英文关键词:fluorine,pre-processing,Enrichment amplification reaction,double electric point potential titration |
| 基金项目:基金项目：国家重点研发计划项目(2017YFD0400401)；江苏高校优势学科建设工程项目(2014-2016)；江苏高校品牌专业建设工程项目（PPZY2015B152）；江苏省大学生创新创业训练计划项目（201910410000007Y）。 |
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| 中文摘要: |
| 【目的】饮食中氟可影响人体健康与安全,简捷准确检测饮食中氟含量就显得十分重要。【方法】以现有GB/T 5009. 18-2003的氟离子电极电位滴定法为基础,以高倍富集放大反应为获得高灵敏度的突破点,以双点电位滴定法为确保方法准确的手段,探寻出灵敏准确测定谷物中微量氟的新方法。以方法的检测限(LOD)、加标回收率和相对标准偏差(RSD)等为衡量指标,通过单因素试验法对影响富集反应的富集剂种类、用量、温度、时间、反应体系酸度(pH)、搅拌速率和洗涤次数等因素考察后,针对富集反应主要影响因素富集剂用量、反应温度、反应时间和反应体系酸度(pH)等用L9(34)正交试验优化获得最适宜的测定条件。【结果】所得最适宜条件为：含Ca2+复合富集剂用量为(m氟/m复合剂) = 1:1×105,反应时间200min,反应温度22℃,反应体系酸度pH 5.5,搅拌速率200~300 r/min,沉淀物洗涤4次。该法的LODF = 5.3×10-3 μg/g,且cF在1.0×10-6 mol/L ~ 1.0×10-1 mol/L内呈良好定量函数关系：E = 38.657 lgc - 174.44 (R2 = 0.996)。加标回收率为91.5 %~100.3 %,测定结果较稳定(RSD≤2.7%)。实样氟含量测定值符合GB 2762-2005氟限量要求。【结论】本法集合了富集反应的高倍放大的效果和双点电位滴定法的高精准的特点,测定选择性高,速度快,灵敏度较高,是种实用可靠的微量氟的定量分析方法。且有易于实现自动化和智能化快捷在线检测的潜能。 |
| 英文摘要: |
| [Objective] Fluoride in diet can affect human health and safety. It is very important and meaningful to detect the fluoride content in diet simply, quickly and accurately. [Method] Based on the current Potentiometric titration with fluoride ion electrod GB/T 5009.18-2003, a new sensitive and accurate method for the determination of trace fluoride in cereals was developed by using high-power enrichment and amplification reaction as a breakthrough point and double-point potentiometric titration as a means to ensure the accuracy of the method. Taking the detection limit (LOD), recovery rate and relative standard deviation (RSD) of the method as indicators, the factors affecting the enrichment reaction, such as the types and dosage of enrichment agents, reaction temperature, reaction time, acidity of reaction system (pH), stirring rate and washing times, were investigated by single factor test. The optimum determination conditions were obtained by L9(34) orthogonal test, which included the amount of concentrator, reaction temperature, reaction time and acidity (pH) of the reaction system. [Result] The optimum conditions were as follows: the dosage of Ca2+ complex concentrator (mF/mcomplex agent) = 1:1×105, the reaction time 200 min, the reaction temperature 22 C, Acidity of the reaction system pH 5.5,the stirring rate 200~300 r/min, and washing the precipitate 4 times. The limit LODF of this method is 5.3×10-3 μg/g, and the cF has a good quantitative function in the range of 1.0×10-6 mol/L to 1.0×10-1 mol/L: E = 38.657lgc - 174.44 (R2 = 0.996). The recovery of standard addition was 91.5%~100.3%, and the results were stable (RSD ≤ 2.7%). The measured fluorine content of the sample meets the requirements of GB 2762-2005 fluorine limit. [Conclusion] This method combines the high magnification effect of enrichment reaction and the high accuracy of double-point potentiometric titration. It has high selectivity, fast determination speed and high sensitivity. It is a practical and reliable quantitative analysis method for trace fluorine. And it has the potential of easy automation and intelligent on-line detection. However, the method still has some drawbacks of tedious operation, which deserves further improvement. |
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