Direct measurement of elemental mercury using multidimensional gas chromatography with microwave-induced helium plasma atomic emission spectroscopy

Microwave-induced helium plasma atomic emission spectroscopy permits direct measurement of picogram levels of elemental mercury in various matrices when combined with multidimensional gas chromatography. Two columns with different stationary phases provide excellent separation for elemental mercury, and multidimensional analysis improves the reliability, performance, and system cleanliness of atomic emission detection. The possibility of false positive identification is substantially eliminated, and excellent sensitivity for the target compound was attained with the use of two selective columns and atomic emission detection at 254 nm. A flame ionization detector was incorporated as part of the system configuration to increase analytical platform capability and flexibility. Elemental mercury was measured in gas matrices over a range of 0.1-170 ug/m3 having a correlation coefficient of R2 = 0.9995, a precision of less than 5% relative standard deviation (n = 10), and a measured recovery exceeding 99% in natural gas as a model matrix. The total analysis time is less than 10 min. Only a small 1 mL sample volume is needed, and the described approach does not rely on any form of sample enrichment. The utility of multidimensional gas chromatography with microwave-induced helium plasma atomic emission spectroscopy is demonstrated with challenging industrial applications, such as the measurement of elemental mercury in natural gas, industrial solvents, and vapor generated from ruptured compact fluorescent light bulbs.