Kev ceev faj thiab tiv thaiv kev ntsuas pH meter
Ua ntej ua haujlwm, kev ncaj ncees ntawm cov electrodes yuav tsum tau kuaj ua ntej. Tam sim no, feem ntau ntawm cov electrodes siv nyob rau hauv pH meters yog composite electrodes, thaum cov laus tiam pH meters tseem siv iav electrodes thiab calomel electrodes. Raws li kev siv dav dav ntawm cov khoom siv hluav taws xob, cov hauv qab no feem ntau tham txog cov khoom siv hluav taws xob sib xyaw.
Feem ntau muaj ob hom kev sib xyaw electrodes siv nyob rau hauv lub chaw soj nstuam: tag nrho kaw thiab tsis kaw. Cov hom kaw tag nrho yog qhov tsawg thiab feem ntau yog tsim los ntawm cov lag luam txawv teb chaws. Ua ntej siv cov khoom siv hluav taws xob sib xyaw, ua ntej xyuas seb lub iav qhov muag puas muaj qhov tawg lossis tawg. Yog tias tsis yog, siv cov tshuaj pH tsis haum rau ob-point calibration. Thaum cov nyees khawm qhov chaw thiab txoj kab nqes tuaj yeem hloov kho rau tus nqi pH, feem ntau suav hais tias yog siv tau. Txwv tsis pub, kev kho electrode ua kom muaj peev xwm ua tau raws li tus neeg siv phau ntawv.
Txoj kev ua kom yog raus rau hauv 4% hydrogen fluoride tov rau li 3-5 vib nas this, tshem tawm thiab yaug nrog dej distilled, ces tsau rau hauv ib tug 0.1mol / L hydrochloric acid tov rau ob peb teev, yaug kom huv si nrog dej distilled, thiab ces calibrate. Ntawd yog, siv cov tshuaj tsis haum nrog tus nqi pH ntawm 6.86 (25 degree) rau qhov chaw. Tom qab hloov kho, xaiv lwm qhov pH tsis haum rau kev kho qhov nqes hav. Yog tias nws tsis tuaj yeem hloov kho, hloov cov electrode. Rau cov khoom siv hluav taws xob uas tsis muaj nyob hauv, yuav tsum tau muab cov tshuaj siv sab nraud ntawm 3mol / L potassium chloride tov rau hauv. Yog li ntawd, nws yog ib qho tsim nyog los xyuas seb cov tshuaj potassium chloride hauv cov electrode puas siab dua 1/3. Yog tias tsis yog, 3mol / L cov tshuaj potassium chloride yuav tsum tau ntxiv. Yog tias cov tshuaj poov tshuaj chloride tshaj qhov chaw ntawm lub qhov me me, co tawm cov tshuaj poov tshuaj chloride ntau dhau, tso cov tshuaj hauv qab lub qhov me me, thiab xyuas seb puas muaj npuas hauv cov tshuaj. Yog tias muaj npuas, maj mam coj mus rhaub cov electrode kom tshem tawm tag nrho.
Thaum siv, cov roj hmab saum lub electrode yuav tsum tau tev tawm kom pom cov qhov me me. Txwv tsis pub, lub siab tsis zoo yuav raug tsim tawm thaum lub sij hawm tsom xam, ua rau cov tshuaj potassium chloride tsis tuaj yeem hloov pauv ions nrog cov tshuaj ntsuas los ntawm cov iav qhov muag teev, uas yuav ua rau cov ntaub ntawv ntsuas tsis raug. Tom qab kev ntsuas tiav lawm, cov roj hmab yuav tsum tau rov qab thiab lub qhov me me yuav tsum tau muab kaw. Tom qab ntxuav lub electrode nrog dej distilled, nws yuav tsum tau tsau rau hauv 3mol / L potassium chloride tov kom cov electrode noob moist. Yog tias pom tias cov tshuaj tiv thaiv tau ploj ua ntej siv, cov electrode yuav tsum tau tsau rau hauv 3mol / L potassium chloride tov rau ob peb teev kom ua tiav lub xeev ntsuas zoo. Hauv kev siv tswv yim, nws tau pom tias qee cov kws tshuaj ntsuam xyuas cov khoom siv hluav taws xob zoo li iav electrodes thiab tsau lawv hauv dej distilled ntev. Qhov no yog qhov tsis raug, vim tias nws tuaj yeem txo qhov concentration ntawm cov tshuaj potassium chloride hauv cov khoom siv hluav taws xob sib xyaw, ua rau muaj qhov tsis txaus ntseeg cov tshuaj tiv thaiv electrode thaum ntsuas thiab qhov kawg ntsuas cov ntaub ntawv tsis raug. Yog li ntawd, cov khoom siv electrodes yuav tsum tsis txhob muab tso rau hauv dej distilled ntev.
