基于低场核磁共振（LF-NMR）弛豫特性的油脂品质检测研究
Quality assessment of oils and fats based on the LF-NMR relaxometry characteristics
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摘要: 研究了低场核磁共振（LF-NMR）检测过程中的仪器参数、检测温度及体积等对大豆油、棕榈油和猪油弛豫特性检测结果的影响,并给出了适用于含固态脂类油脂样品的LF-NMR检测条件,即:TR=2000ms,τ=250μs,EchoCount=6000个,检测体积2.5mL,检测温度50℃。并应用建立的方法对多种地沟油样品进行了检测。结果表明,基于油样的LFNMR弛豫特性,可有效区分8种固态油样和10种液态地沟油,检测正确识别率可达75%和100%,有效避免了假阳性,且S21峰比例面积可有效反映样品的掺杂梯度变化,说明了该方法对固态和液态地沟油也具有较好的识别能力,在后期油脂品质检测应用中具有较好的可行性。Abstract: The effects of the LF-NMR instrument parameters, detection temperature and volume on the stability and reproducibility of oils' relaxometry characteristics results had been investigated with the taken soybean oil, palm oil and lard as the samples. The results indicated that good stability and reproducibility could be guaranteed if choosing the following parameters, such as TR=2000ms, τ=250μs, EchoCount=6000, and before the measurement, a sample of 2.5mL should be stabilized at 50℃. Then the method was employed to discriminate 8 solid oil samples, 10 liquid hogwash oil samples. The result indicated that the proposed methodology was a useful tool to authenticate the hogwash oils, and the correct recognition rate was 75% and100%, respectively, and the false positive rate had been effectively avoided. Meanwhile, the difference of S21 peak area could reflect the adulterated ratio, which means that. The developed method had a good possibility to be used to assess the oil quality in the future.
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