A fluid sample is brought into contact with a pair of spaced apart electrodes and {HEAD ~ a voltage} is applied across {TAIL ~ the electrodes} 
is applied across
A fluid sample is brought into contact with a pair of spaced apart electrodes and { HEAD ~ a voltage } is applied across { TAIL ~ the electrodes }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL