河水溶解无机营养盐样品保存与过滤方式对其测定的影响:以黄河水为例

Effects of storage and filtration methods of riverine dissolved inorganic nutrients on their determination: a case study of the Yellow River water sample

对营养盐样品的及时预处理及恰当的保存是保证数据真实可靠的前提条件。本文以高浊度的黄河为例,探究了硅酸盐样品冷冻保存与加氯化汞常温保存两种方法之间的区别,结果表明两种方法不存在显著性差异。通过对比现场过滤冷冻保存于9 mL真空涤纶树脂(PET)管与延迟过滤冷冻保存于125 mL高密度聚乙烯(HDPE)瓶中两种营养盐样品预处理方法,探讨了延迟过滤时间对营养盐测定的影响,发现亚硝酸盐、硝酸盐、磷酸盐未受到过滤时间延长的影响,铵盐因过滤时间延长受到悬浮颗粒物和浮游植物的影响而结果偏低11%~46%,硅酸盐存在差异可能是由储存容器和体积的不同引起,而非过滤时间延长导致。

Timely pretreatment and proper storage of nutrient samples are the pre-conditions to ensure the reliability of data. In this study, we examine the differences between frozen storage and preservation with mercury chloride at room temperature for dissolved silicate in the Yellow River water sample that is characterized of high turbidity. We found out that there was no significant difference between the two storage methods. We compared in-situ filtration(freezing stored in 9 mL vacuum polyethylene terephthalate tube) and delayed filtration(freezing stored in 125 mL high density polyethylene bottle) for the nutrients, and discussed the effects of delayed filtration time on nutrients data quality. Nitrite, nitrate and phosphate were not affected by prolonged filtration time, while ammonium was significantly impacted by a decrease of 11%~46%, possibly due to suspended particulate matter adsorption and/or phytoplankton assimilation. As for silicate, storage container and its volume may play a major role in silicate storage while the prolongation of filtration time is much less important.