DART can ionize organic substance on solid surface in atmospheric pressure. By utilizing this feature, we analyzed organic contaminant adhered to a metal part (Fig. 1).
We wiped of the organic contamination on the metal surface by using ceramic fiber paper and analyzed it by holding up the ceramic fiber paper directly into the DART ion source. Peaks with 74 interval at m/z 371, m/z 445, and m/z 519 are observed (Fig. 2; upper). The elemental compositions of these ions were deduced from their respective accurate masses (Table 1) and they were found to be poly(dimethylsiloxane) series.