Such pH monitoring can be automated and the additional base or buffer metered into {HEAD ~ the aqueous solution} as needed to maintain {TAIL ~ the pH} 
as needed to maintain
Such pH monitoring can be automated and the additional base or buffer metered into { HEAD ~ the aqueous solution } as needed to maintain { TAIL ~ the pH }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL