analyte of interest one or more couplets each comprising a designated precursor ion 204 and corresponding designated ion fragment 206 may be stored in a trigger entry 202 in the trigger data set 200 the corresponding trigger time window 208 is also determined and stored block 504 the confirmatory data set 300 will also be determined and stored in data storage 17 block 506 as will be understood typically an ion will fragment into a plurality of ion fragments accordingly in many instances the confirmatory data couplets 302 corresponding to a trigger couplet 202 will share the same precursor ion 204 304 as will be understood the trigger data 200 designated precursor ion s 204 and designated ion fragment s 206 together with the corresponding trigger time window 208 and the related confirmatory data 300 for numerous analytes of interest may be previously calculated and stored as a library of data in the data storage 17 and simply indexed and retrieved by the user and the cpu 12 utilizing the i o device 16 the duty cycle list 400 is initiated being populated with couplets 402 of designated precursor ion 204 and designated ion fragment 206 from the trigger data 200 which have a trigger time window 208 which commences or coincides with the beginning of the analysis period fig4 a illustrates an example duty cycle list 400 as one may exist at the commencement of an analysis period the user will then typically input a command to commence an analysis period typically via the i o device 16 upon receipt of which the trigger engine 14 is.