(a). The graph shows the 2,4An ions obtained from the dp10 CSA and DS chains with the ions with the arrows indicating ions with the diagnostic characteristics discussed in the text. With the exception of the 2,4A3, these crossring appeared only in the tandem mass spectrum of CSA and were absent for DS. (b).The zoom in of some of these particular diagnostic ions is shown below the graph. (c). Structure with fragment ions obtained from the diagnostic precursor ion with the 2,4A and 0,2X fragments shown in red.