定量核磁共振氢谱法测定饮料中山梨酸含量

Determination of sorbic acid content in beverages by 1H-quantitative nuclear magnetic resonance

中文关键词:  饮料  山梨酸  定量核磁共振  重水  化学位移

英文关键词:beverages  sorbic acid  1H-quantitative nuclear magnetic resonance  deuterated water  3-(trimethylsilyl)propanoic-2,2,3,3-d4 acid sodium salt  chemical shift

中文摘要:

      目的 建立定量核磁共振氢谱法检测饮料中山梨酸含量的方法。方法 采用核磁共振技术测定饮料中山梨酸的含量。样品中山梨酸的含量与1H的核磁共振信号峰成正比; 氘代溶剂为重水, 内标物“3-(三甲基硅基)氘代丙酸钠”[3-(trimethylsilyl)propanoic-2,2,3,3-d4 acid sodium salt, TMSP-d4]的甲基峰在重水中的化学位移定标为0.00 ppm, 确定δ=1.84 (±0.05) ppm的多重耦合峰为山梨酸特征化学位移峰, 外标法定量; 氢谱脉冲序列为zgpr以压制水峰信号, 样品扫描次数为16次。结果 方法学验证结果表明该方法在7.5~300.0 μg/mL质量浓度范围内线性关系良好: Y=0.01019X+0.36268, r2>0.99; 检出限和定量限分别为2.5 g/mL、7.5 g/mL; 加标回收率为81.8%~102.6%; 相对标准偏差为0.69%~5.27%。结论 该方法前处理简单、结果准确, 大幅缩短了样品检测时间, 可用于饮料中山梨酸含量的快速、高通量检验, 具有良好的潜在应用前景。

英文摘要:

      Objective To establish a method for determination the content of sorbic acid in beverages by 1H-quantitative nuclear magnetic resonance (1H-qNMR). Methods Nuclear magnetic resonance was used to measure the sorbic acid (SA) content in beverages. The content of SA in the sample was proportional to the signal peak of 1H nuclear magnetic resonance; deuterated water (D2O) was used as the deuterated solvent, and the methyl peak of the internal standard substance “3-(trimethylsilyl)propanoic-2,2,3,3-d4 acid sodium salt” (TMSP-d4) in deuterated water was calibrated to a chemical shift of 0.00 ppm. The multiple coupling peak at δ=1.84 (±0.05) ppm was identified as the characteristic chemical shift peak of sorbic acid, and quantification was performed using the external standard method. The ‘zgpr’ pulse sequence was employed for 1H-NMR to suppress the residual water peak signal, with 16 scans acquired for each sample. Results Method validation indicated a good linear relationship within the concentration range of 7.5–300.0 μg/mL: Y=0.01019X+0.36268, r2>0.99. The limits of detection and limits of quantitation were 2.5 μg/mL and 7.5 μg/mL, respectively. The recovery rates ranged from 81.8% to 102.6%, with relative standard deviations of 0.69%–5.27%. Conclusion This method features simple sample pretreatment, accurate results, and significantly reduces detection time. It is suitable for rapid, high-throughput analysis of sorbic acid in beverages and shows promising potential for practical applications.