Karl Fischer reagent xav tau qib siab ntawm freshness. Thaum yuav Merck Karl Fischer reagent, xyuam xim rau hnub tsim khoom thiab siv tam sim ntawd raws li qhov siv tau. Nws yuav tsum tau khaws cia kom deb ntawm lub teeb kom ntev lub sij hawm cia.
Tam sim no, Merck Karl Fischer reagent tsis muaj pyridine tau tawm los, uas tau daws qhov teeb meem uas pyridine reagent muaj pungent tsw. Txawm li cas los xij, hauv kev txiav txim siab, nws pom tias qhov kawg taw tes hloov pauv ntawm pyridine uas muaj Karl Fischer reagent yog pom tseeb, thiab cov xim ntawm cov reagent ntawm qhov kawg taw tes yog me ntsis xim av daj. Raws li kev paub dhau los, nws tuaj yeem kwv yees los ntawm qhov muag liab qab tias qhov kawg taw tes yog los, thaum qhov kawg taw tes hloov pauv ntawm pyridine dawb Karl Fischer reagent tsis pom tseeb, thiab cov xim ntawm cov reagent ntawm qhov kawg taw tes yog xim av tsaus.
Muaj feem xyuam ntawm Merck Karl Fischer reagent yam tsis muaj pyridine.
Anhydrous methanol yog dav siv los ua tus qauv hnyav. Feem ntau cov organic tebchaw, saturated los yog unsaturated hydrocarbons, dav inorganic compounds, acidic oxides, thiab ib co organic thiab inorganic ntsev yuav siv tau. Txawm li cas los xij, qee qhov ketones thiab aldehydes tsis tuaj yeem cuam tshuam nrog methanol. Yog tias nws pom tias cov tshuaj tiv thaiv tsis tuaj yeem cuam tshuam, tsis muaj qhov kawg, thiab cov tshuaj tiv thaiv txuas ntxiv, cov lus nug ntawm seb puas muaj cov kev mob tshwm sim yuav tsum tau txiav txim siab. Thaum muaj qhov tshwm sim sab nraud, nws tsuas siv ob peb feeb xwb, tab sis nws tau mus lawm. Nyob rau lub sijhawm no, glycol methyl ether tuaj yeem siv los hloov methanol kom tau txais qhov ntim titration tas li, thiab cov ntsiab lus dej ntawm qee cov khoom siv tshuaj ketone thiab aldehyde tuaj yeem txiav txim siab yam tsis muaj kev siv tshuab tshwj xeeb.
Tus nqi pH siab dhau thiab siab alkalinity ntawm cov qauv kuj tseem yuav ua rau muaj kev cuam tshuam sab nraud, uas yog, tsis tu ncua kev cuam tshuam yam tsis muaj qhov kawg. Lub sijhawm no, yog tias tus nqi pH siab dhau lawm, cov tshuaj tsis tuaj yeem siv los kho tus nqi pH. Yog tias alkalinity siab dhau lawm, toluenic acid thiab salicylase tuaj yeem muab ntxiv kom yooj yim rau cov tshuaj alkalinity, tab sis acetic acid tsis tuaj yeem siv.
Thaum lub sij hawm methanol dej titration (feem ntau hu ua dawb paug titration), yog tias cov xim hauv cov tshuaj tiv thaiv lub raj mis maj mam hloov ntawm cov xim tsis muaj xim mus rau xim av tsaus, thiab cov cuab yeej tseem tsis muaj qhov kawg, nws yuav tsum tau txiav txim siab tias Karl Fischer reagent tau ua tsis tiav, thiab cov cuab yeej tseem tsis muaj qhov kawg, reagent yuav tsum tau hloov.