弱酸性体系(pH =6.0)及加热80℃的条件下,表面活性剂十二烷基硫酸钠(SDS)增敏Cr(Ⅵ)能加快过氧化氢氧化亚甲基蓝的褪色反应,当反应其他条件不变时,亚甲基蓝褪色速度与Cr(Ⅵ)的浓度成正比.本实验探讨了测定方法的优化条件,并用该方法测定了废水中Cr(Ⅵ)的含量.结果表明:当Cr(Ⅵ)物质的量浓度在0～5.438 85E-05 mol·L-1范围内遵守朗伯比尔定律,其线性回归方程ASDS660=-8 712.5x(SDS) +0.574 4,RSD为0.0845％;平均回收率为96.28％;该方法具有较高灵敏度、准确度,操作简便,可用此方法可有效地测定废水中的Cr(Ⅵ)的含量.

目的:测定黑木耳、白木耳中Zn、Fe、Cu、Mn微量元素的含量.方法:采用HNO3和HClO4 (4+1)消解样品,火焰原子吸收光谱法对黑木耳、白木耳中Zn、Fe、Cu、Mn的含量进行测定.结果:黑木耳、白木耳中均含有Zn、Fe、Cu、Mn且含量有一定差异.测定的RSD＜ 0.9301％,回收率在95.25％ ～ 101.88％之间.结论:黑木耳、白木耳中4种微量元素含量的测定可为进一步探讨木耳的食用价值和微量元素关系提供参考数据.

Adopting HNO3-HClO4 (4:1) digestion samples, we determined the contents of trace elements Cu and Mn in leaves and stems of Chinese cabbage by using the flame atomic absorption spectrometry (FAAS) method, to study the food and industrial application value of Chinese cabbage. The results showed that, both Cu and Mn contents had significant difference in leaves and stems of Chinese cabbage, and the contents of Mn were higher than Cu in leaves and stems, in addition, the contents of the two trace elements were higher in leaves than those in stems.

[Objective] The aim was to determine the content of Cu, Mn in peels of kumquat. [Method] HNO3 and HClO4(4 +1) were used to digest the sample and flame atomic absorption spectrometry was applied to determine the content of Cu and Mn in the peels of kumaquat. [Result] The content of Mn was more than Cu,while the recovery rate was 98.0%~105.0% with the RSD≤1.62%. [Conclusion] This result was satisfied and could provide reference data for further study and clinical application of kumquat.