Determination of Lead and its Compounds in Workplace Air by GFAAS with Dynamic Tri-magnetic Field Zeeman Background Correction

Objective To establish an analytical method for the determination of lead and lead compounds in the air of workplace by GFAAS with dynamic tri-magnetic field Zeeman effect background correction.

Methods Air sample was collected with microporous filter membrane, digested with perchloric acid+nitric acid (1:9, V:V), fixed the volume to 25 mL with 1% nitric acid and determined by GFAAS at wavelength 283.3 nm with a dynamic tri-magnetic field Zeeman effect background correction mode.

Results Using a dynamic tri-magnetic field mode, the absorption value and calibration curve could be obtained both from bi-magnetic field mode and tri-magnetic field mode.There was a good linear relationship for the concentration of lead in the range of 0~800 μg/L by using a bi-magnetic field mode for 0~100 μg/L with a correlation equation of A=2.76×10^-3C+2.08×10^-3(r=0.9975) and a characteristic concentration of 1.58 μg/L; and using a tri-magnetic field mode for 100 μg/L~800 μg/L with a correlation equation of A=(4.05×10^-3+9.67×10^-4C)/(1+6.50×10^-4C; r=0.9970) and a characteristic concentration of 4.51 μg/L.The minimum detectable concentration of this method was 2.6 μg/L.The recovery rate was 95.1%~104.8%, RSD was 2.4%~4.5%.

Conclusion With the advantage of two kinds of magnetic field mode, the linear range could be effectively extended.This method was simple, accurate, sensitive and suitable for the determination of lead and lead compounds in the air for different concentration levels at the same time.