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    基于电感耦合等离子体质谱法的桦树皮药材中5种重金属元素的定量分析与风险评估

    Quantitative Analysis and Risk Assessment of 5 Heavy Metal Elements in Birch Bark Medicinal Materials Based on Inductively Coupled Plasma Mass Spectrometry

    • 摘要: 取桦树皮药材粉末样品0.25 g,加入7 mL硝酸,过夜,于120 ℃预消解20 min,再置于微波消解仪中,程序升温至180 ℃消解20 min,冷却至室温,于120 ℃赶酸至1 mL,用2%(体积分数)硝酸溶液定容至50 mL,摇匀,采用电感耦合等离子体质谱法(ICP-MS)测定溶液中5种重金属元素(铅、镉、砷、汞、铜)的含量,在线引入含锗、铋、铟的混合内标溶液。采用单因子污染指数法与内梅罗综合污染指数法评估桦树皮药材受重金属元素的污染情况;基于每日最大可耐受摄入量、靶标危害系数和致癌风险因子这三种指标,对重金属元素可能造成的人体健康风险进行评估。结果显示,5种目标元素的质量浓度在一定范围内和对应的响应强度与内标响应强度的比值呈线性关系,检出限(3s/k)为0.000 2~0.005 mg·kg−1。对实际样品进行精密度试验,测定值的相对标准偏差(n=6)均小于5.0%。按照标准加入法进行回收试验,回收率为90.9%~106%。方法用于分析30批桦树皮药材样品,结果显示来自不同产地、不同批次样品中5种目标元素含量存在一定差异;单因子污染指数与内梅罗综合污染指数分别小于0.8,0.7,说明桦树皮药材污染程度为安全水平;健康风险评估显示,每日最大可耐受摄入量低于每日暂定耐受摄入量,致癌风险因子远低于1×10−6 mg·(kg·d)−1,但来自内蒙古的3批样品中铅元素的靶标危害系数大于0.01,提示桦树皮药材中铅元素可能存在潜在的非致癌风险,应予以持续监控。

       

      Abstract: The birch bark medicinal material powder sample (0.25 g) was taken, and 7 mL of nitric acid was added. The mixture was left overnight, and pre-digested at 120 ℃ for 20 min, then placed in a microwave digestion instrument and digested at 180 ℃ for 20 min by heating program. After cooling to room temperature, the mixture was acidified to 1 mL at 120 ℃ and made its volume up to 50 mL with 2% (volume fraction) nitric acid solution. After shaking well, the 5 heavy metal elements (lead, cadmium, arsenic, mercury, and copper) in the solution were determined by inductively coupled plasma mass spectrometry, with an online addition of a mixed internal standard solution containing germanium, bismuth and indium. The contamination status of birch bark medicinal materials by heavy metals were evaluated using the single-factor pollution index method and the Nemerow comprehensive pollution index method. The potential human health risks posed by heavy metals were assessed based on 3 indicators, including the maximum tolerable daily intake, the target hazard quotient, and the carcinogenic risk factor. As shown by the results, linear relationships between the ratios of the corresponding response intensity to the internal standard response intensity and mass concentrations of the 5 target elements were kept in definite ranges, with detection limits (3s/k) in the range of 0.000 2−0.005 mg·kg−1. Test for precision was conducted on an antual sample, with RSDs (n=6) of the determined values less than 5.0%. Test for recovery was made by the standard addition method, giving results in the range of 90.9%−106%. The method was applied to the analysis of 30 batches of birch bark medicinal material samples. The results showed that there were certain differences in the contents of the 5 target elements among samples from different producing areas and different batches. The single-factor pollution index and the Nemerow comprehensive pollution index were less than 0.8 and 0.7, respectively, indicating that the pollution degrees of birch bark medicinal materials were at safe level. The health risk assessment showed that the maximum tolerable daily intakes were lower than the provisional tolerable daily intakes, and the carcinogenic risk factors were significantly below 1×10−6 mg·(kg·d)−1. However, the target hazard quotients of lead element in 3 batches of samples from Inner Mongolia were greater than 0.01, suggesting that lead element in birch bark medicinal materials may pose a potential non-carcinogenic risk, which should be subject to continuous monitoring.

       

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