Dab tsi yog ob-point calibration ntawm pH meter?
Rau precision-qib pH meters, ntxiv rau "kev tso chaw" thiab "kub them nyiaj" kev hloov kho, kuj tseem muaj kev hloov kho electrode "slope", uas yuav tsum tau muaj ob tus qauv buffers rau calibration. Feem ntau, pH=6.86 lossis pH=7.00 yog siv rau "qhov chaw" calibration ua ntej, thiab tom qab ntawd raws li acid-base mob ntawm cov tshuaj ntsuam xyuas, pH=4.00 (acidic) los yog pH=9.18 los yog pH=10.01 (alkaline) buffer tov yog xaiv rau "kev kho txoj kab nqes", cov txheej txheem ua haujlwm tshwj xeeb yog:
(1) Ntxuav thiab qhuav cov electrode, muab tso rau hauv pH =6 86 los yog pH =7 00 txheem tov, thiab tso qhov kub thiab txias qhov rooj rau ntawm qhov kev daws kub. Tom qab qhov taw qhia tus nqi ruaj khov, kho qhov chaw qhov rooj kom qhov ntsuas ntsuas tus nqi yog tus nqi pH ntawm tus qauv kev daws teeb meem.
(2) Tshem tawm cov electrode, ntxuav nws thiab tig nws qhuav, thiab muab tso rau hauv cov txheej txheem thib ob. Tom qab qhov taw qhia tus nqi stabilizes, kho txoj kab nqes pob qhov ntsuas ntawm qhov ntsuas kom qhov ntsuas qhov ntsuas yog tus nqi pH ntawm tus qauv thib ob.
(3) Ntxuav cov electrode thiab tig nws qhuav, ces muab tso rau hauv pH6.86 los yog pH7.00 txheem tov. Yog tias qhov yuam kev dhau 0.02pH, rov ua cov kauj ruam (1) thiab (2). Txog thaum tus nqi pH raug tuaj yeem tshwm sim hauv ob txoj kev daws teeb meem yam tsis tau kho cov pob qhov rooj.
(4) Tshem tawm cov electrode, ntxuav nws thiab tig nws qhuav, kho qhov pH kub them pob qhov rooj rau cov qauv ntsuas kub, muab cov electrode tso rau hauv cov qauv kev daws teeb meem, co nws thiab muab tso rau hauv, thiab kev nyeem ntawv yuav ruaj khov.
