“…There are many kinds of H 2 S probes which have been designed and synthesized to date [ 57 , 58 , 59 ]. In the subsequent sections, we summarize two different mechanisms of H 2 S detection reported over the last 7 years [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 ]. These include probes ( Table 2 ) based on the principles of nucleophilic attack [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ] and reduction of azide groups [ 75 , 76 , 77 , 78 , 79 , 80 ].…”