Suitable means include, but are not limited to, {HEAD ~ the periodic addition} of base to {TAIL ~ the aqueous solution} or the use of buffers 
to
Suitable means include , but are not limited to , { HEAD ~ the periodic addition } of base to { TAIL ~ the aqueous solution } or the use of buffers
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH