Sohler A, Wolcott P, Pfeiffer C C
Clin Chim Acta. 1976 Aug 2;70(3):391-8. doi: 10.1016/0009-8981(76)90352-1.
The determination of Zn in fingernails directly using the graphite furnace presented certain difficulties due to the anomalous behavior of the analyte in the furnace. The appearance of two peaks which were due to Zn and not to any background interference was noted. The Zn value obtained by adding the area of these two peaks compared fairly well with Zn levels determined by wet ashing and subsequent determination either in the furnace or flame. Wet ashed samples gave only a single peak. It was possible to produce a model of the phenomenon with various Zn salts in a non aqueous matrix. Under these conditions ZnSO4 and ZnO gave a discretely different peak from ZnC12 or metallic Zn. Several tissues such as serum, whole blood, cuticle, and hair were examined for multiple peak formation. Direct determination of Zn in fingernails with the graphite furnace is possible for certain applications such as the determination of Zn levels of white spots in fingernails. For this purpose it is possible to use a sample size as small as 20 mug using the 2138 Zn line. This allows one to run several determinations on a single white spot. However, where sample size is not a limitation, wet ash digestion prior to determination in the furnace is probably the preferred procedure.
由于分析物在石墨炉中的异常行为，直接使用石墨炉测定指甲中的锌存在一定困难。注意到出现了两个峰，这两个峰是由锌引起的，而非任何背景干扰。将这两个峰的面积相加得到的锌值与通过湿式灰化以及随后在炉中或火焰中测定得到的锌水平相当吻合。湿式灰化的样品只给出一个峰。在非水基质中用各种锌盐可以建立该现象的模型。在这些条件下，硫酸锌和氧化锌给出的峰与氯化锌或金属锌的峰明显不同。对血清、全血、表皮和头发等几种组织进行了多峰形成的检测。对于某些应用，如测定指甲白斑中的锌水平，用石墨炉直接测定指甲中的锌是可行的。为此，使用213.8nm的锌线，样品量小至20微克即可。这使得可以在单个白斑上进行多次测定。然而，在样品量不受限制的情况下，在炉中测定之前进行湿式灰化消化可能是首选方法。
