蛋白核小球藻富集结合XRF光谱测量的水体重金属铬快速检测方法

Rapid Detection Method of Heavy Metal Chromium in Water by Enrichment of Chlorella Pyrenoidosa and XRF Spectrometry

将蛋白核小球藻对重金属Cr的快速高效吸附特性与重金属现场快速检测的X射线荧光(XRF)光谱技术相结合,通过蛋白核小球藻对水体重金属Cr的富集,实现了XRF光谱技术对水体重金属Cr的快速检测。研究表明:蛋白核小球藻对重金属Cr在5 min即可达到高效稳定的吸附,吸附反应的最佳pH值范围为6~8,最佳蛋白核小球藻的质量浓度为100 mg·L^(-1);在最佳吸附反应条件下,采用抽滤-滤膜富集方式实现蛋白核小球藻对水体重金属Cr的快速富集,再进行XRF光谱测量,当反应液富集量为10 mL,XRF信号累积时间为2 min时,重金属Cr的Kα特征谱峰净积分荧光强度与待测水体中Cr质量浓度间具有很好的线性关系,相关系数R^(2)为0.9967,水体重金属Cr的方法检测限为0.0299 mg·L^(-1),显著低于《地表水环境质量标准(GB 3838—2002)》中规定的Ⅱ类水中Cr的标准限值0.05 mg·L^(-1)。采用该方法对安徽省合肥市匡河水样进行加标回收测试,重金属Cr的回收率均在90.00%~101.24%范围内,10次重复测量的精密度为1.59%~2.66%,因此蛋白核小球藻富集与XRF光谱测量相结合的方法能够很好地实现实际水体重金属Cr的精准检测。

The rapid and efficient adsorption of heavy metal Cr by Chlorella pyrenoidosa is combined with X-ray fluorescence(XRF)spectroscopy technology for rapid detection of heavy metals in the field.Rapid detection of heavy metal Cr in water is realized by XRF spectroscopy technology.The research shows that Chlorella pyrenoidosa can achieve high-efficient and stable adsorption for heavy metal Cr within 5 min,and the optimal pH value range of adsorption reaction is 6-8.The optimal mass concentration of Chlorella pyrenoidosa is 100 mg·L^(-1).Under the optimal adsorption reaction condition,the rapid enrichment of heavy metal Cr in water by Chlorella pyrenoidosa is achieved by suction filtrationmembrane enrichment,and then XRF spectrometry measurement is performed.When the enrichment volume of the reaction solution is 10 mL,and the XRF signal accumulation time is 2 min,there is a positive linear relationship between the net integral fluorescence intensity of the Kαcharacteristic spectral peak of heavy metal Cr and the concentration of Cr in water to be tested,and the correlation coefficient R^(2) is 0.9967.The detection limit of the method for heavy metal Cr in water is 0.0299 mg·L^(-1),which is significantly lower than the standard limit of 0.05 mg·L^(-1)of Cr in ClassⅡwater stipulated in Environmental Quality Standards for Surface Water(GB 3838—2002).This method is used to test the recovery of water samples from the Kuanghe River in Hefei City,Anhui Province.The recovery rate of heavy metal Cr ranges from 90.00%to 101.24%,and the precision of 10 repeated measurements ranges from 1.59%to 2.66%.Therefore,the accurate detection of heavy metal Cr in actual water can be realized by the enrichment of Chlorella pyrenoidosa and XRF spectrometry.