ICP-MS is a well established analytical technique in the semiconductor industry for essential trace metal characterization in chemical reagents and silicon wafers. Tetracene, Antracene, Pentacene and Rubrene are among the most interesting organic semiconductors for use in molecular electronic devises such as single-crystal Organic Field Effect Transistors (OFETs). One of the most important parameter for fabrication of single-crystal OFETs is the purity of the starting material. As the crystal growth process also results in the chemical purification of the material, several re-growth cycles may be required for improving the field-effect mobility, with the grown crystals used as the starting material for the subsequent re-growth. The number of required re-growth cycles depends strongly on the purity of starting material. We report the application of ICP-MS for impurity analysis in the organic semiconductors. The ICP plasma, where samples are atomized and ionized, generates strong ion current, which is instrumental in achieving exceptional detection limits. Some elements can be measured down to part per trillion range. This study can provide a better characterization of the trace metal impurities in starting material.