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用无火焰原子吸收法测定镉时,由于镉及其化合物易挥发,通常选择较低的灰化温度。若试样组份复杂,基体干扰严重,一般采用少取样,或在有机溶剂萃取分离后再测定。作者在试验中发现,在标准系列(1%HNO_3介质)中加定量铁(浓度为100μg·ml~(-1)),可将灰化温度提高至500℃,所定方法可直接测定化探样品中痕量镉无须分离富集:用NH_4H_2PO_4作基体改进剂,灰化温度可增至1000℃,更有效地驱除了样品基体,方法适用于复杂地质样品(黄铁矿、方铅矿等)中痕量镉的直接测定;用钽处理石墨杯作原子化器,灵敏度高,准确度和精度亦好。测定镉的绝对灵敏度为6.0×10~(-13)g。
Determination of cadmium by flame atomic absorption spectrometry, the cadmium and its compounds volatile, usually choose a lower ash temperature. If the sample composition is complex, serious interference matrix, the general use of less sampling, or organic solvent extraction and separation and then measured. In the experiment, we found that the addition of Fe (100 μg · ml -1) to standard series (1% HNO 3) can increase the ashing temperature to 500 ℃. The method can directly measure geochemical samples In the absence of separation and enrichment of trace amounts of cadmium: NH_4H_2PO_4 as a matrix modifier, ashing temperature can be increased to 1000 ℃, more effectively expelled the sample matrix, the method is suitable for complex geological samples (pyrite, galena, etc.) Direct determination of trace amounts of cadmium; tantalum processing graphite cup atomizer, high sensitivity, accuracy and accuracy is also good. The absolute sensitivity of determination of cadmium 6.0 × 10 ~ (-13) g.