A method of operating an electrostatic trapping mass analyzer, comprising: operating the electrostatic trapping mass analyzer at a maximum resolution so as to acquire a transient signal of a sample; partitioning the transient signal into signal segments; defining a test transient as being equal to a first one of the segments; calculating a mathematical transform of the test transient and thereby generating a spectrum of component frequencies of the test transient; determining a quality metric from the spectrum of component frequencies and comparing the quality metric to either a pre-determined minimum threshold value or a pre-determined maximum threshold value; performing, while the most-recently-determined quality metric is either less than the pre-determined minimum threshold value or greater than the pre-determined maximum threshold value, the steps of: appending a next signal segment onto the test transient; re-defining the test transient as being the previously-defined test transient having the appended next signal segment appended thereto; calculating a mathematical transform of the test transient and thereby generating a new spectrum of component frequencies of the test transient; and re-determining the quality metric from the new spectrum of component frequencies; and setting an instrumental resolution to be employed for subsequent mass spectral data acquisitions in accordance with a length of the most-recently-defined test transient. operating the electrostatic trapping mass analyzer at a maximum resolution so as to acquire a transient signal of a sample; partitioning the transient signal into signal segments; defining a test transient as being equal to a first one of the segments; calculating a mathematical transform of the test transient and thereby generating a spectrum of component frequencies of the test transient; determining a quality metric from the spectrum of component frequencies and comparing the quality metric to either a pre-determined minimum threshold value or a pre-determined maximum threshold value; performing, while the most-recently-determined quality metric is either less than the pre-determined minimum threshold value or greater than the pre-determined maximum threshold value, the steps of: appending a next signal segment onto the test transient; re-defining the test transient as being the previously-defined test transient having the appended next signal segment appended thereto; calculating a mathematical transform of the test transient and thereby generating a new spectrum of component frequencies of the test transient; and re-determining the quality metric from the new spectrum of component frequencies; and appending a next signal segment onto the test transient; re-defining the test transient as being the previously-defined test transient having the appended next signal segment appended thereto; calculating a mathematical transform of the test transient and thereby generating a new spectrum of component frequencies of the test transient; and re-determining the quality metric from the new spectrum of component frequencies; and setting an instrumental resolution to be employed for subsequent mass spectral data acquisitions in accordance with a length of the most-recently-defined test transient. <EOS>