Electrothermal desolvation-enhanced microplasma optical emission spectrometry for sensitive determination of Cd, Zn Pb and Mn in environmental water samples

Herein, a novel electrothermal desolvation (ED) introduction approach is developed to enhance the analytical sensitivity of the point discharge (PD)-based microplasma-optical emission spectrometric (PD-MIP-OES) system for detecting trace Cd, Zn, Pb and Mn in environmental water samples. Liquid samples are converted into aerosols through a miniature ultrasonic nebulizer, and subsequently desolvated by electric heating at 350 °C. The analytes obtained after condensation (referring to the smaller apertures aerosols and volatile analytes after ED and condensation) are excited and detected by PD-MIP-OES. For a 160 μL liquid sample, analysis is completed within 10 s, achieving a desolvation efficiency of 93 %. Under the optimized conditions, the detection limits for Cd, Zn, Pb and Mn are 1.3, 1.2, 2.4 and 2.1 μg L^-1, respectively. Compared to traditional direct ultrasonic nebulization introduction, sensitivity increases by 17, 12, 10 and 14 times, respectively. The accuracy and practicality of the proposed method are verified by measuring certified reference material and several real water samples. The ED-enhanced PD-MIP-OES device presented is compact, easy to operate, and capable of rapid analysis, which provides a convenient and reliable tool for the field analysis of Cd, Zn, Pb and Mn in environmental water samples.