Accurate mass measurments are done on the Thermo Exactive Plus using methods equilivent to APCI or ESI (More details provided in method descriptions) at a typical resolving power of 140,000 at m/z 200. The mass accuracy is typically within 2 ppm but can be slightly larger. With this service, we will try and provide elemental information about the compound. There is need to provide information about the range of elements to use in the calculation of the elemental formulas, this is one reason we request the proposed elemental formula on the submission forms. If this information is incomplete or inaccurate, the elemental analysis may not be obtainable. However, the accuracy of the mass measurement would allow for calculating elemental formulas when better information is available.