极地研究 ›› 2003, Vol. 15 ›› Issue (4): 261-266.

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锌镉还原法测量海水硝酸盐中锌卷的形状和面积

金明明;唐仁友;陈建芳;卢勇;陈波   

  • 出版日期:2003-12-30 发布日期:2003-12-30

ZINC-COIL SHAPES AND ITS AREAS IN SEAWATER NITRATE MEASUREMENT OF ZINC CADIUM METHOD

  • Online:2003-12-30 Published:2003-12-30

摘要:

《海洋调查规范》(GB1 2 763.4 91 )的锌镉还原法规定 ,与 5 0mL水样起反应的锌卷面积是 30cm2 。在面积完全相同的条件下 ,将规定的 1 .5cm内径的圆筒式锌卷改成曲线内间距 2πa不小于 1 0mm的阿基米德螺旋式锌卷。用螺旋式测出白令海海水的硝酸盐浓度比圆筒式的高了约 1 1 %。采用天然海水或人工海水来配制高、中、低三档浓度的硝酸盐标准溶液 ,进行螺旋式锌卷的面积试验。结果证实 :《海洋调查规范》(GB1 2 763.4 91 )规定的反应面积没有过量。在 1— 1 7μM浓度范围内 ,两种锌片批号F980 72和 931 2 1 0 (上海化学试剂公司 )引起浓度的相对误差超过 1 0 %。

关键词: 硝酸盐;锌;表面积;海水;分析方法

Abstract:

According to the zinc cadmium reduction method in China Specification for Oceanographic Survey, surface area of circular zinc coil of 1.5 cm diameter is 30 cm 2 for the 50 mL sample. We improved the circular coil to the Archimedes′ spiral coil of the interval 2πa greater than 10 mm, the nitrate concentrations with the spiral coil are 11% higher than that with the circular coil. In the area tests of the spiral coil and for 4 μM concentrations of standard nitrate solution, the concentration value becomes saturated beyond 35 cm 2. As for 14 μM concentration, the concentration value approaches saturated until at 45 cm 2. So the 30 cm 2 area of the circular coil in the Specification is not enough. In the range between 1 and 17 μM, the relative errors of nitrate concentrations with the spiral coils of the F98072 and 931210 serial numbers (Shanghai Chemical Reagent Co.) are about 19%-23%.