以不同品种茶树鲜叶及茶多糖为材料,比较了酸浸提、沸水浸提和碱熔灰化前处理对氟离子选择电极法测定氟含量的影响。结果表明,无论对茶叶还是茶多糖,碱熔灰化处理所测氟含量均极显著高于酸浸提和沸水浸提法(P<0.01)。茶叶水浸提法氟含量显著或极显著高于酸浸提法(P<0.05,P<0.01)。对碱熔灰化-氟离子电极法进行精密度及回收率实验,结果表明茶叶和多糖中氟的回收率分别达到91.07%~94.40%和83.04%~90.32%,而RSD分别为1.44%~2.54%和0.68%~1.03%,说明该方法稳定性好,精密度高,检测结果可靠,更能真实反映茶叶及茶多糖的氟含量,适宜于茶叶及茶提取物全氟的测定。
The influence of sample pretreatment methods including boiling water extraction (BWE),acidic solution extraction (ASE) and alkalizing and burning to ash(ABA) on fluorine content in tea and tea polysaccharides was investigated. The results showed that the fluorine contents of tea and tea polysaccharide pretreated with ABA were much higher than that of BWE and ASE method (P<0.01). The fluorine content of tea pretreated with BWE was significantly higher than ASE (P<0.05, P<0.01). The further test on precision and recovery of ABA and fluoride ion selective electrode method was investigated. Results showed that the recovery of fluorine in tea and tea polysaccharide were 91.07%-94.40% and 83.04%-90.32%, respectively, with RSD of 1.44%-2.54% for tea and 0.68%-1.03% for tea polysaccharide, which indicated the result of fluorine determination by this method could represent the real fluorine content in tea and tea polysaccharide with accuracy, reliability and stability. It was also suggested that the ABA and fluoride ion selective electrode method could be more suitable for determination of total fluorine in tea and tea extracts.
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