PH meter - Kev txiav txim siab thiab kev hloov kho ntawm nruab nrab pH
Tag nrho cov kab mob kis tau cuam tshuam los ntawm pH ntawm ib puag ncig uas lawv nyob. Feem ntau, qhov pom ntawm cov tsiaj xaiv nqaim qhov pH ntau yam uas lawv loj hlob. Qee zaum, acidity lossis alkalinity ntawm qhov nruab nrab tuaj yeem ua raws li qhov kev xaiv loj hlob. Rau biochemical xeem media, txawm li cas los xij, pH ntau yam uas cov kab mob ua rau pom tk kev ua hauv lub substrate yog nqaim dua li pH ntau yam xav tau rau kev loj hlob: yog li ntawd, nws yog ib qho tseem ceeb uas yuav tau kho cov pH ntawm cov xov xwm mus rau qhov xav tau ntau yam. Thaum lub chaw soj nstuam npaj qhov nruab nrab raws li qhov nruab nrab muaj pes tsawg leeg, pH yuav tsum tau kuaj xyuas thiab kho. Nws yuav tsum tau taw qhia tias txawm tias npaj txhij-ua hluavtaws lub cev qhuav dej nruab nrab yog muab los ntawm cov chaw tsim khoom (tshwj xeeb tshaj yog rau qee qhov nruab nrab lub cev qhuav dej), qhov kawg pH yuav tsum tau ntsuas tom qab ua qhov kev sim nruab nrab.
Qhov tseeb tshaj plaws los ntsuas pH ntawm qhov nruab nrab yog nrog pH meter. Ua ntej siv, nws yuav tsum tau calibrated nrog tus txheej txheem buffer tov ntawm pH paub (feem ntau pH yog 4 txog 7). Yaug cov electrode ntawm pH meter nrog dej distilled thiab muab tso rau hauv cov kab lis kev cai nruab nrab hauv lub beaker, thiab tom qab ntawd nyeem cov pH ntawm kab lis kev cai nruab nrab ntawm qhov ntsuas pH. Txhua lub chaw tsim khoom muab cov lus qhia ntxaws ntxaws rau txhua hom pH meter.
Thaum npaj cov kab lis kev cai nruab nrab, PH tuaj yeem hloov kho tau yooj yim los ntawm kev siv lub ntsuas pH nrog cov tshuab nplawm. Cov kab lis kev cai nruab nrab yuav tsum tau npaj rau hauv lub thawv (xws li lub lauj kaub loj) uas tuaj yeem sib tov tsis tu ncua. los yog Teflon-pob hlau nplaum. Lub pH ntawm agar-muaj nruab nrab yuav tsum tau kho tom qab thawing, uas yog yooj yim ua nrog ib tug heatable magnetic stirrer. Thaum kho cov pH, siv cov txheej txheem tsis daws teeb meem ntawm pH paub los ntsuas pH ntsuas ua ntej. Tom qab ntawd muab cov khoom siv hluav taws xob sib xyaw thiab cov ntsuas kub tsis kam (yog tias muaj) hauv qhov nruab nrab, maj mam ntxiv cov nyiaj tsim nyog ntawm hydrochloric acid thiab sodium hydroxide los ntawm qhov kawg ntawm lub beaker kom deb ntawm electrode, kom qhov nruab nrab tuaj yeem ncav cuag thiab tswj cov pH uas xav tau.
Kev them nyiaj kub ntawm pH meter yuav tsum coj mus rau hauv tus account qhov kub thiab txias ntawm lub electrode system: nyob rau hauv ib co dilutions thiab media, pH hloov nrog kub. Rau cov kua tawm thiab dilutions, pH feem ntau tuaj yeem hloov kho thiab ntsuas ntawm 25 degree lossis ntawm qhov kub uas lawv siv.
Lub pH ntawm agar nruab nrab yuav tsum tau kho tom qab dissolving, thiab qhov kub ntawm dissolving yog siab tshaj 45 degree: yog li ntawd, pH ntawm cov khoom nruab nrab yuav tsum tau txiav txim siab ntawm nws siv kub. Lub sijhawm no, yuav tsum tau siv lub taub hau lub taub hau sib xyaw electrode, thiab qhov kub thiab txias ntawm pH meter yuav tsum tau ntsuas manually. Thaum npaj cov kab lis kev cai nruab nrab, yog tias nws tau txiav txim siab tias pH ntawm kab lis kev cai nruab nrab yog qhov sib txawv ntawm lub xeev melting thiab lub xeev solidifying, nws txhais tau hais tias muaj qhov yuam kev hauv kev kho cov pH.
Ib yam li ntawd, thaum lub nruab nrab npaj tau kub-sterilized (xws li, autoclaved), nws kuj yuav raug hloov pH. Rau qhov nruab nrab lub cev qhuav dej, cov chaw tsim khoom tau muab qhov no los txiav txim siab, thiab feem ntau tsis tas yuav kho pH, tab sis pH ntawm qhov nruab nrab yuav tsum tau ua tib zoo xyuas. Yog hais tias pH ntawm lub dehydrated agar nruab nrab yuav tsum tau kho thaum lub sij hawm redissolution los yog npaj, nws yog qhov zoo tshaj plaws los kho nws nrog lim-sterilized hydrochloric acid thiab sodium hydroxide tov tom qab sterilization kauj ruam kom tsis txhob tsim overheating ntawm nruab nrab. Thaum npaj cov ntawv xov xwm nrog cov khoom siv raw lossis cov tshuaj sib txawv, pH ntawm cov xov xwm yuav tsum tau kuaj xyuas tom qab autoclaving. Tsis tas li ntawd, yog tias pH ntawm qhov nruab nrab pom tau hloov pauv tib yam tom qab txhua lub autoclave, pH tuaj yeem hloov kho kom tsim nyog thaum npaj qhov nruab nrab. Txawm li cas los xij, nws tseem yuav tsum tau txiav txim siab qhov pH kawg ntawm qhov nruab nrab tom qab ua kom tsis muaj menyuam.
