基于普通汞灯光源的横向塞曼效应背景校正大气汞检测方法研究

精确的背景校正决定着冷原子吸收法检测痕量汞的检测下限,研究了基于普通汞灯光源的横向塞曼效应背景校正大气汞检测方法.汞灯光源253.65 nm共振谱线在磁场中垂直于磁场方向产生σ-,σ+和π三个线偏振光.利用超高分辨率光谱仪获取不同磁场强度下汞样品池对σ-,σ+和π线偏振光的吸光度,分析横向塞曼效应背景校正方法所需的最小磁场强度;在1.78 T强磁场强度下,分析了窄带吸收气体苯、宽带吸收气体丙酮对横向塞曼效应背景校正大气汞检测方法可能存在的干扰;利用σ-,σ+作为背景光,π线偏振光作为吸收光,对不同长度的饱和汞蒸气样品池测量,精确背景校正后,吸光度拟合曲线R值达到0.99.实验结果表明基于普通汞灯光源的横向塞曼效应背景校正大气汞检测方法可以实现精确背景校正,能够应用于大气环境痕量汞检测.

New transverse Zeeman effect method for mercury detection based on common mercury lamp

The accurate background correction can determine the minimum limit of trace mercury measurement in atmosphere by the cold vapor atomic absorption method. This paper studies a new method of mercury detection using the common mercury lamp as sources which correct the background according to the transverse Zeeman effect. The resonance spectral line (253.65 nm) of the meccury lamp generates σ^-, σ⁺, and π linear polarized light in the vertical direction of the magnetic field. This study obtains mercury absorbance of σ^-, σ⁺, and π light in different magnetic field intensity by using ultra-high resolution spectrometer, then gets the minimum field intensity of the method. We discuss the existing possible interference caused by benzene with narrow-band absorption and acetone with broadband absorption under 1.78 T magnetic field intensity. Taking σ^- and σ⁺ as background light, and π as absorption light, we quantify the saturated mercury vapor cell with different lengths. With the accurate background correction, the R value of absorption fitting curve can achieve 0.99. Results indicate that the method can accomplish the job of accurate background correction and can be applied to trace mercury measurement in atmosphere.
Keywords： cold vapor atomic absorption transverse Zeeman effect linear polarized mercury