目前市面上柠檬酸硼膳食补充剂的商品信息中缺乏对其确切结构的描述,其质量参差不齐,甚至存在安全隐患,这与常规分析手段无法满足对柠檬酸硼络合物的结构和质量评价有关.此外,对于柠檬酸硼络合物合成的相关研究也鲜有报道.综合运用核磁共振(11 B NMR,13 C NMR)、红外光谱(FT-IR)和热分析法协同密度泛函理论计算(DFT)和Chemdraw软件预测的分析策略,探究了不同酸碱度(pH)下硼酸和柠檬酸(钠)络合作用的规律.结果表明:硼酸与柠檬酸的络合能力和形成的络合物结构会随着pH的变化而发生改变,在pH=9.5 时硼酸与柠檬酸络合程度达到最高,此时合成的络合物Na-Cit-BpH9.5 包含五元和六元 2 种单环阴离子络合物.本研究可为柠檬酸硼及其他含硼膳食补充剂的开发利用与质量控制提供方法与策略.
Effect of pH on The Synthesis of Boric Acid/Citrate(Sodium)Complex and Their Analytical Strategies
At present,the product information of boron citrate dietary supplements on the market lacks a description of its exact structure,the quality is uneven,and there are even safety risks.This is relat-ed to the fact that conventional analytical methods cannot meet the structure and quality evaluation of boron citrate complexes.Furthermore,the related studies on the synthesis of boron citrate complexes have rarely been reported.In this thesis,the complex of boric acid and citrate(sodium)at different pHs was explored by using 11 B NMR,13 C NMR,FT-IR and thermal analysis methods with density functional theory(DFT)and analysis strategies predicted by Chemdraw software.The results showed that the complexing capacity and complex structure of boric acid and citric acid changed with the change of pH.The degree of complexation between boric acid and citric acid reached the highest at pH=9.5,and formed the resultant complex Na-Cit-BpH9.5 containing two five-and six-membered sin-gle-cyclic anion complexes.This research can provide methods and strategies for the development,uti-lization and quality control of boron citrate and other boron-containing dietary supplements.
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