Standard method for pH meter calibration solution configuration
1) pH4, Potassium Hydrogen Phthalate Standard Buffer:
Ua kom raug hnyav 10.12g ntawm potassium hydrogen phthalate [KHC8H4O4] qhuav ntawm 115 ± 5 degree rau 2 mus rau 3 teev, ntxiv dej kom yaj thiab dilute rau 1000ml.
2) pH7, phosphate standard tsis (pH7.4):
Ua kom raug hnyav 4.303 g ntawm anhydrous disodium hydrogen phosphate thiab 1.179 g ntawm poov tshuaj dihydrogen phosphate, uas tau qhuav ntawm 115 ± 5 degree rau 2 mus rau 3 teev, ntxiv dej kom yaj thiab dilute rau 1000 ml.
Ntxiv: Phosphate Standard Buffer (pH6.8) Ua kom raug hnyav 3.533g ntawm anhydrous disodium hydrogen phosphate thiab 3.387g ntawm potassium dihydrogen phosphate, qhuav ntawm 115 ± 5 degree rau 2 mus rau 3 teev, ntxiv dej kom yaj thiab dilute rau 1000ml.
3) pH9, borax txheem tsis:
Precisely hnyav 3.80g ntawm borax [Na2B4O7·10H2O] (ceeb toom: tsis txhob huab cua), ntxiv dej kom yaj thiab dilute mus rau 1000ml, muab tso rau hauv ib lub raj mis polyethylene, thiab kaw kom nruj kom tsis txhob sib cuag nrog carbon dioxide nyob rau hauv cov huab cua.
Cov ntsiab lus
Kev txiav txim siab los ntawm kev siv pH ntsuas tam sim no, muaj ob hom kev ntsuas calibration buffers rau domestic pH meters los yog acidity ntsuas hauv Suav teb:
1) Qhov ntawd yog, cov qauv kev daws teeb meem yog muaj nyob rau hauv kev ua lag luam, thiab feem ntau muab khaws cia rau hauv lub raj mis polyethylene kaw. Cov txheej txheem kev daws teeb meem feem ntau tsim nyog rau kev khaws cia rau 1 mus rau 2 lub hlis ntawm chav tsev kub. Thaum pom muaj turbidity, pwm los yog nag lossis daus, nws siv tsis tau lawm. Khaws rau hauv lub tub yees ntawm 4 degree, thiab cov txheej txheem siv tsis raug tso cai rov qab.
2) Koj tseem tuaj yeem yuav qhov tsis koj tus kheej thiab rov qab mus rau kev teeb tsa. Txawm li cas los xij, thaum cov chaw tsim khoom lag luam xa cov khoom muag, vim tias lub teb chaws tau teev tseg tias qee cov kua lossis tshuaj tsis raug tso cai hauv kev xa khoom, nws tsuas tuaj yeem nruab nrog PH tsis tuaj yeem qhuav. Thaum siv nws, tus neeg siv khoom yuav tsum tau teeb tsa los ntawm nws tus kheej, tsuav nws yog yaj hauv lub pre-boiled 15 Yaug cov reagent seem hauv lub hnab reagent kom zoo hauv dej deionized rau ~ 30 feeb. Tom qab ntawd ncuav nws mus rau hauv 250 ml volumetric hwj, dilute mus rau lub cim, thiab co zoo.
