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茶叶科学 ›› 2010, Vol. 30 ›› Issue (6): 440-444.doi: 10.13305/j.cnki.jts.2010.06.006

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应用低场核磁共振技术测定茶叶含水量

李然1, 陈珊珊1, 俞捷1, 杨磊1, 汪红志1,2, 张学龙1,2,*   

  1. 1. 上海理工大学医疗器械与食品学院,上海 200093;
    2. 上海医疗器械高等专科学校,上海 200093
  • 收稿日期:2010-06-01 修回日期:2010-08-10 发布日期:2019-09-11
  • 通讯作者: xuelongz@yahoo.com.cn
  • 作者简介:李然(1986— ),女,吉林蛟河人,汉族,硕士研究生,研究方向为低场核磁共振技术。
  • 基金资助:
    上海市重点学科(P0502)、上海市高校科技发展基金(07ZZ93, 10YZ237)、上海市重大科研项目基金(09QT1405900)资助项目

Determination of Water Content of Tea by Low Field Nuclear Magnetic Resonance Technology

LI Ran1, CHEN Shan-shan1, YU Jie1, YANG Lei1, WANG Hong-zhi1,2, ZHANG Xue-long1,2,*   

  1. 1. College of Medical Instrument and Food Sciences, University of Shanghai for Scinece and Technology, Shanghai 200093, China;
    2. Shanghai Medical Instrumentation College, Shanghai 200093, China
  • Received:2010-06-01 Revised:2010-08-10 Published:2019-09-11

摘要: 本研究应用一种更为快速、准确、无损的低场核磁共振技术来测定茶叶的含水量。实验通过标定6种不同质量的纯水标样的FID信号幅值,拟合出水分含量与FID信号幅值的直线方程,再选取5个茶叶样分别测量其FID信号幅值,根据拟合直线换算成茶叶含水量,同时将核磁共振法测得的含水量结果与国家标准的103℃恒重法比较分析。实验结果表明:应用低场核磁共振测定茶叶含水量方便迅速,结果稳定准确,通过与国家标准的茶叶含水量103℃恒重法对比发现,核磁共振法测得的含水量偏高不到1%,这是由于烘干法无法将茶叶内部的结合水完全烘干所致,而核磁共振法测量的是茶叶内部游离水和结合水的总和。

关键词: 茶叶, 含水量, 低场核磁共振, FID

Abstract: Research on the determination of water content of tea by using low field NMR instrument has been conducted. The purpose is to develop a more rapid, accurate and nondestructive method to measure the water content of tea. In this experiment, six pure water samples with different weights were prepared as standard samples to test their FID signals. FID signal data were fitted to a line equation. Five tea samples were prepared to test their FID signals and calculate the water content of tea by the fitting equation, then compare the results with national standard method. Result showed that the determination of water content of tea by low field NMR could obtain a more rapid and accurate result. The result by low field NMR is about 1% higher than that of the national standard method, because the drying method can’t dry the bound water completely,but the NMR measures both the content of free water and bound water.

Key words: tea, water content, low-field NMR, FID signal

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