Lub luag haujlwm ntawm kev tiv thaiv pab pawg yog cais cov pab pawg ua haujlwm tshwj xeeb thaum lub sijhawm sib xyaw ua ke, tiv thaiv lawv los ntawm kev cuam tshuam, thiab tsuas yog tshem tawm cov pab pawg tiv thaiv tom qab ua tiav cov tshuaj tiv thaiv tshwj xeeb kom rov ua haujlwm ntawm lub hom phiaj molecule. Cov txheej txheem ntawm kev tshem tawm cov pab pawg tiv thaiv feem ntau yuav tsum muaj mob me me kom tsis txhob ua rau lub hom phiaj molecule. Piv txwv li, txoj kev tshem tawm ROH los ntawm kev tiv thaiv cawv feem ntau yog tsim ethers (ROR ') lossis esters (ROCOR'), thiab tom qab ntawd hydrolyze lossis acidify lawv nyob rau hauv cov xwm txheej tsim nyog.
Hauv cov ntsiab lus, lub luag haujlwm ntawm kev tiv thaiv cov pab pawg hauv PNA synthesis yog qhov tseem ceeb, vim nws ua kom muaj txiaj ntsig zoo ntawm cov khoom siv molecules, zam kev tsis muaj lub hom phiaj, thiab tuaj yeem xaiv tshem tawm thaum tsim nyog kom tau txais cov khoom PNA purified.