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建立一种利用元素分析-同位素比率质谱法测定大米中碳同位素比值方法。样品进样量在200~400μg之间,分析时间小于700 s。方法的精密度和准确度可靠,所用标准品与证书值的差值为0~0.003%,在证书质量控制要求内,对大米测定结果标准偏差为0.002%~0.015%。应用该方法对五常大米及周边地区大米60批次进行检测。结果表明,同一地区不同品种的大米碳稳定同位素没有显著差异(p>0.05),不同地区的大米碳稳定同位素有明显差异(p<0.05),碳稳定同位素可应用于大米的产地溯源。
A Method for the Determination of Carbon Isotope Ratio in Rice Using Element Analysis - Isotope Ratio Mass Spectrometry. Sample injection volume between 200 ~ 400μg, analysis time is less than 700s. The precision and accuracy of the method are reliable. The difference between the standard used and the certificate is 0 ~ 0.003%. The standard deviation of the determination results of rice is 0.002% ~ 0.015% within the requirements of certificate quality control. This method is used to test 60 batches of rice in Wuchang rice and the surrounding area. The results showed that there was no significant difference (p> 0.05) in the stable carbon isotopes of different rice varieties in the same area (p <0.05), and stable carbon isotopes could be applied to traceability of rice origin.