摘要：

为实现水溶液中腐殖酸含量的准确、便捷测定，开发了一种高效简便的紫外分光光度法。首先，配制质量浓度为1.00~20.00 mg/L的系列腐殖酸溶液，采用全波段扫描方法测定溶液吸光度，基于2.00~20.00 mg/L的溶液在各波长下的吸光度和1.00 mg/L溶液对应波长下吸光度的比值与波长的关系进行拟合，根据拟合曲线平稳性，选取250、260、275、282、340 nm共5个单波长，采用具有全波段扫描功能的紫外分光光度计测定这5个单波长对应的吸光度，并得到拟合方程，所得拟合方程拟合效果均较好，其中以275 nm单波长拟合结果为最优。之后采用不具有全波段扫描功能的普通紫外分光光度计进行单波长测定，结果表明其在275 nm单波长下可实现腐殖酸含量的准确测定。为进一步验证普通紫外分光光度计单波长测定法的可行性，配制非上述质量浓度范围内的腐殖酸（3.00 mg/L和5.00 mg/L），分别利用275 nm单波长测定（普通紫外分光光度计）和全波段测定法，依据相应的拟合方程计算腐殖酸质量浓度，结果显示两种方法结果无显著差异。因此，普通紫外分光光度计单波长测定方法用于测定腐殖酸浓度时简便、快捷，适用于水溶液中腐殖酸含量的快速测定。

关键词: 腐殖酸, 紫外分光光度计, 单波长, 全波段扫描

Abstract:

To achieve accurate and convenient determination of humic acid content in aqueous solutions, an efficient and simple ultraviolet spectrophotometry method had been developed. Firstly, a series of humic acid solutions with a concentration of 1.00-20.00 mg/L were prepared, and the absorbances of the solutions were measured using a full band scanning method. Based on the relationship between the ratio of the absorbance at each wavelength of the solution with a concentration of 2.00-20.00 mg/L to the absorbance at the corresponding wavelength of the solution with a concentration of 1.00 mg/L and wavelength, a fitting was performed. According to the stationarity of the fitting curves, five single wavelengths of 250, 260, 275, 282, and 340 nm were selected, and the absorbances corresponding to these five single wavelengths were measured using a ultraviolet spectrophotometer with full band scanning function. The fitting equations were obtained, and the fitting effects were good. Among them, the fitting result of 275 nm single wavelength was the best. Afterwards, a ordinary ultraviolet spectrophotometer without full band scanning function was used for single wavelength measurement, and the results showed that it could accurately determine humic acid content at a single wavelength of 275 nm. To further verify the feasibility of the single wavelength determination method by ordinary ultraviolet spectrophotometer, humic acids (3.00 mg/L and 5.00 mg/L) were prepared outside the above mass concentration range. The humic acid mass concentration was calculated using 275 nm (ordinary ultraviolet spectrophotometer) single wavelength measurement and full band measurement methods, respectively, based on the corresponding fitting equation. The results showed no significant difference between the two methods. Therefore, single wavelength determination method by ordinary ultraviolet spectrophotometer was simple and fast for determining the concentration of humic acid, and was suitable for rapid determination of humic acid content in aqueous solutions.

Key words: humic acid, ultraviolet spectrophotometer, single wavelength, full-wavelength scanning

中图分类号: 

• X703