We use a Sciex Model API 365 triple stage mass spectrometer. The instrument can be tuned for greater or less accuracy depending upon sample quantity.
Greater accuracy requires more sample.
The mass range for direct detection of ions is 30 - 3000 a.m.u. Larger molecules up to ca. The accuracy of protein determined through deconvolution of multiply charged ions is greater than that for ions which fall within the 30-3000 a.m.u. range due to the averaging out of the error in the individual ion measurements. We have an Ion Charge State Deconvolution Chart on Excel that you may download and use to input ions and examine possible MWs under various hypothetical charge states. Conversely, you can enter MWs and view theoretical ions that ought to appear in the data output.