a hydrogen sensitive dye disposed in or placed on said container, said hydrogen sensitive dye outputting a detectable signal in response to {HEAD ~ a presence} or absence of {TAIL ~ said molecular hydrogen} 
a hydrogen sensitive dye disposed in or placed on said container , said hydrogen sensitive dye outputting a detectable signal in response to { HEAD ~ a presence } or absence of { TAIL ~ said molecular hydrogen }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL