To further exclude {TAIL ~ CO2} from the etching environment, all water used to prepare {HEAD ~ etchant solution} and all water used to prepare rinse solutions for the electrodes following etching steps is boiled for one minute prior to use 
To further exclude { TAIL ~ CO2 } from the etching environment , all water used to prepare { HEAD ~ etchant solution } and all water used to prepare rinse solutions for the electrodes following etching steps is boiled for one minute prior to use
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH