Electro-Filtering Spray Ionization Source for Soil Analysis

An electro-filtering spray ionization source for ambient mass spectrometry is reported. The ion source was assembled with a conical metal filter with a paper cone. The performance of the new ion source was characterized by the analysis of soil. Soil was directly introduced into the filter-paper cone and solvent was added. Ions were produced at the filter-paper tip when a high voltage was applied. The results by electro-filtering spray ionization were in good agreement with the results using conventional electrospray ionization with complex sample preparation. Advantages of electro-filtering spray ionization include simplicity, speed, and convenient operation that may allow in situ analysis in ambient atmospheric conditions.