Kungani ukumunca kwe-methylene blue kushintsha ngokugxila kwayo

Thatha ibhodlela elilodwa lengxube egxilile ye-methylene blue bese uthela ezingilazini ezimbili. Gcwalisa eyokuqala ngengxube egxilile, neyesibili ngengxube ukugxila kwayo okuncishiswe ngokuphindwe kashumi. Ingilazi yesibili inombala okhanyayo, njengoba kulindelekile. Bhekisisa, uzobona ukuthi kukhona okunye okushintshile. Umthunzi wombala usuguqukile. Enye ingxube ithambekele kokuluhlaza okwesibhakabhaka esicwebile, kanti enye ithambekele kokuluhlaza okwesibhakabhaka okunomthunzi onsomi. Ukunciphisa ukugxila akugcinanga ngokwehlisa ukushuba kombala. Kushintshe ukuthi yiluphi uhlobo lwamakhemikhali olumunca kakhulu.

Umqondo obangela lolu shintsho ulula. I-methylene blue encibilikile ayilona uhlobo olulodwa lwamakhemikhali. I-cation eyodwa kadayi, ebizwa ngokuthi i-monomer, inganqwabelana nenye i-cation, ubuso bubhekene, ukuze kwakheke i-dimer, kanti ama-dimer angakhula abe amaqoqo amakhulu. Uhlobo ngalunye lunesipekthramu salo sokumunca. Okubikwa i-spectrophotometer kuyisamba sazo zonke izinhlobo ezikhona engxubeni ekuleyo cuvette, ngaphansi kwalezo zimo. Shintsha ingxube, nesipekthramu siyashintsha, ngisho noma ingqikithi kadayi ilandela isilinganiso esiqondile sokunciphisa ukugxila.

I-monomer ne-dimer zimunca ngokuhlukile

Cabanga nge-monomer njengekhadi eliyisicaba elinenkokhiso kagesi evumayo esabalele ohlelweni lwamasongo alo. Amakhadi amabili anjalo angalala ubuso bubhekene. Izinkokhiso ezivumayo ziyaxoshana, kodwa izindawo eziyisicaba ezinamasongo anephunga elimnandi ngokwesakhiwo samakhemikhali ziyakhangana ngokunqwabelana, kanti amanzi azungezile nama-ion anezinkokhiso eziphambene anciphisa lokho kuxoshana. Umphumela uba ipheya elibambene elinezimo zama-electron ezabiwe. Ukuguquka kwalo okuvunyelwe kwenzeka emandleni aphezulu kunokuguquka kwe-monomer, ngakho ibhande le-dimer livela kubude begagasi obufushane kunebhande le-monomer, kanti amaqoqo amakhulu afaka iqhaza elibonakala njengehlombe ohlangothini oluqhubekela kokuluhlaza okwesibhakabhaka.

Lapho ukugxila kuphansi kakhulu emanzini ahlanzekile, ama-monomer yiwona amaningi futhi ibhande lobude begagasi obude liyabusa. Njengoba ukugxila okuphelele kukhuphuka, uhlobo olungamapheya luthatha ingxenye eyandayo, nebhande lobude begagasi obufushane liyakhula uma liqhathaniswa nelokuqala. Ngakho isilinganiso samabhande amabili sibonisa ukwakheka kwengxube, hhayi ukugxila okuphelele ngokuqondile. Isilinganiso esithathwe kubude begagasi obubodwa asikwazi ukuhlukanisa lezi zinhlobo ezimbili ngaphandle kokuqagela ukuthi yiluphi uhlobo olukhona.

Yingakho izipekthramu eziyizinkomba kufanele njalo zihambisane nezimo zazo. Inkomba yesipekthramu ye-methylene blue ibeka etafuleni izindawo zamabhande kanye nesincibilikisi, usawoti okhona, i-pH, izinga lokushisa nebanga lokugxila okwakusetshenziswe ukuzithola. Uma ucaphuna isiqongo ngaphandle kwalezo zimo, inani alinayo imininingwane eyanele. Amalabhorethri amabili angaba neqiniso womabili ngezipekthramu ezihlukile zikadayi ofanayo ngoba akale izingxube ezihlukile.

Yini eshintsha ukulingana

Ukugxila kuyisici esiyinhloko. Ukwakheka kwe-dimer kudinga ukuba ama-monomer amabili ahlangane, ngakho ingxenye yayo ikhula ngokushesha kunokukhula okuqondile kwengqikithi kadayi. Amanani angaguquki okubunjwa kwe-dimer emanzini abikiwe asezingeni lezinkulungwane nge-molar eduze kwezinga lokushisa lasekamelweni, ngakho ingxenye ye-dimer ikhuphuka ngokushesha ebangeni le-micromolar. Ukufaniswa kwemodeli nedatha okubanzi, okusuka kudayi osezingeni le-micromolar kuya kwele-millimolar, kwathola ukuthi i-tetramer yayisivele ifaka iqhaza elingaphezu kukaziro ngaphansi kuka-34 micromolar. Lokhu kuxwayisa ngokwethemba imodeli yezinhlobo ezimbili kuphela lapho ukugxila kungamashumi e-micromolar. Izingxenye eziqondile zincike endaweni ingxube ekuyo, yingakho lesi sihloko sichaza ukuthi ushintsho luya ngaphi kunokuba sinikeze itafula lokuguqula elisebenza kuzo zonke izimo.

Usawoti uyisici sesibili. Ama-ion ancibilikile anciphisa ukuxoshana kwama-cation amabili, ngakho ukwengeza i-sodium chloride namanye ama-electrolyte afanayo kusunduza ingxube iye kuma-dimer namaqoqo, noma ukugxila kukadayi kungashintshi. Lo mphumela uyabonakala ezifundweni zokuhlangana kwe-methylene blue ezingxubeni zikasawoti nezasemanzini, lapho udayi osukela cishe ku-1 micromolar kuya ku-3.4 millimolar wakalwa ku-sodium chloride esukela ku-0 kuya ku-0.15 molar. Kulokho kufaniswa kwemodeli nedatha, ingxenye ye-tetramer yafinyelela cishe ku-0.93 lapho kokubili udayi nosawoti kwakuphezulu. Ngakho isipekthramu esiqoshwe emanzini nesinye esiqoshwe engxubeni kasawoti enokugxila okufana nokoketshezi lomzimba akuzona izinkomba ezingasetshenziswa esikhundleni sezinye.

Izinga lokushisa lidonsela ngakolunye uhlangothi. Ukunqwabelana kukhulula amanzi abebambekile futhi kuphikiswa ukunyakaza okubangelwa ukushisa, ngakho ukufudumeza ingxube kuvame ukuhlukanisa amanye ama-dimer abuye abe ama-monomer, kuyilapho ukupholisa kukhuthaza ukuhlangana. I-enthalpy yokuhlukana etholwe ngokufanisa imodeli nedatha inenani elinegethivu, cishe u-minus 30 kilojoules per mole ebangeni lika-282 kuya ku-333 kelvin, okuqinisekisa ukuthi ukuhlangana kukhipha ukushisa. Isampula ebandayo ekalwa ngokushesha ngemva kokukhishwa esiqandisini ingabonakala inamaqoqo amaningi kunesampula efanayo ekalwa ngemva kokufinyelela izinga lokushisa lasekamelweni.

Isincibilikisi sibeka isimo esiyisisekelo. Amanzi, ngenxa yomthelela wawo onamandla wokuhlanganisa izinto ezingahlangani kahle nawo, akhuthaza ama-cation kadayi ayisicaba ukuba anqwabelane. Ama-alcohol afana ne-ethanol ne-methanol azungeza futhi ancibilikise amasongo kangcono, aphule amaqoqo, ngakho udayi onokugxila okufanayo ubonakala unama-monomer amaningi ku-ethanol kunasemanzini. Izincibilikisi ezinganikeli ngamaprothoni ezixutshwe namanzi zenza okufanayo: ezingxubeni zamanzi ne-DMSO ku-293 kelvin, ukwengeza i-DMSO kwanciphisa ukwakheka kwe-dimer, okubonisa ukuthi ukwakheka kwamanzi kuyisici esiqhuba ukunqwabelana. Izinto ezisebenza ebusweni bengxube zidinga ukuqashelwa kuzo zombili izinhlangothi. Ngaphezu kokugxila okubucayi kokwakheka kwama-micelle, ama-micelle angancibilikisa ama-monomer ngamanye ngamanye futhi abuyisele isipekthramu efana neye-monomer. Ngaphansi kwalelo zinga, into esebenza ebusweni enenkokhiso ephambene ingakhuthaza ukunqwabelana esikhundleni salokho: kudayi ongu-100 micromolar, ukwakheka kwama-polymer okuqhutshwa yi-SDS kwafinyelela esiqongweni eduze kuka-4 millimolar SDS, cishe uhhafu wezinga lokwakheka kwama-micelle, ngaphambi kokusatshalaliswa kabusha lapho leyo nto yengezwa kakhulu. Ucwaningo ngemithelela yokusebenzisana kukadayi nesincibilikisi kanye nezindawo ezihlelekile ezipekthramini ze-methylene blue lubonisa ukuthi indawo eseduze kwamangqamuzana, hhayi ukugxila kwengxube kuphela, inquma kakhulu amabhande abonwayo.

I-pH ibaluleka ikakhulukazi ezingeni eliphansi noma eliphezulu kakhulu. Ebangenini eliseduze nokungathathi hlangothi elisetshenziswa emisebenzini eminingi yaselabhorethri, i-methylene blue ihlala isesimweni sayo esijwayelekile se-cation eluhlaza okwesibhakabhaka, futhi ukuhlangana yikhona okubusa izinguquko zesipekthramu. I-asidi noma i-base enamandla, ukusabela kwe-redox okukhiqiza isimo se-leuco esingenambala, noma ukubopha kumaprotheni nezinhlayiya, ngakunye kwengeza izimo ezingaphezu kwepheya le-monomer ne-dimer. Lapho isipekthramu sishintsha ngemva kokwengeza i-buffer, hlola ukuthi i-buffer inosawoti noma izingxenye ezibophayo yini ngaphambi kokuthi uthi konke kubangelwa yi-pH kuphela. Inkomba yamakhemikhali nokwengezwa kwamaprothoni igcina le mibuzo yokuthi yiluphi uhlobo olukhona ihlukene nombuzo wokuhlangana oxoxwa lapha.

Kungani umugqa oqondile we-Beer-Lambert ugoba

Ubudlelwano be-Beer-Lambert buthi isilinganiso sokumunca silingana nekhono lokumunca liphindwe ngokugxila, kuphindwe ngobude bendlela yokukhanya. Bungumthetho wokubala. Bucabanga ukuthi izinto ezibalwayo zihlala zifana njengoba inani lazo lishintsha: uhlobo olulodwa olumuncayo, isipekthramu engaguquki, akukho kushintsha kwamakhemikhali ngokugxila, ukukhanya kokuhlola okunobude begagasi obubodwa, akukho kuhlakazeka noma ukukhishwa kokukhanya kabusha, nokukhanya okudlula ngempela endleleni yobude obubikiwe.

Ukuhlangana kwephula umbono wokuqala. Ngokwezibalo, isilinganiso sokumunca esiphelele sisalokhu siyisamba sezinhlobo: ubude bendlela yokukhanya buphindwe ngekhono lokumunca lohlobo ngalunye, kuphindwe ngokugxila kwalolo hlobo. Uhlobo ngalunye lulandela umthetho. Ingxube ayiwulandeli, ngoba ukugxila kwezinhlobo akukhuli ngokomugqa oqondile nengqikithi kadayi. Ngakho ijika lokulinganisa lesilinganiso sokumunca ebhandeni le-monomer uma liqhathaniswa nengqikithi kadayi liqala liqondile lapho ukugxila kuphansi kakhulu, bese ligobela phansi njengoba ukugxila kukhuphuka, ngoba ukwanda ngakunye okungeziwe kuletha ingxenye encane ye-monomer. Ijika elifundwa ebhandeni le-dimer ligobela ngakolunye uhlangothi. Ucwaningo lokuhlangana lukhomba yona kanye le ndlela njengomthombo wokuphambuka okubonwayo ku-Lambert-Beer. Ukufanisa umugqa oqondile nengxenye egobile bese uwelulela ngaphandle kwebanga kuyiphutha elivamile. Umugqa usebenza kuphela ngaphakathi kwebanga nasengxubeni yezinye izakhi lapho wakhiwa khona.

Ukunciphisa ukugxila kudala ugibe oluhlobene nalolu. Ukunciphisa ukugxila kwengxube eyisisekelo ukuze kufinyelelwe ebangeni lethuluzi akusigcini isilinganiso sezinhlobo. Ingxube eku-cuvette iphinde ifinyelele ekulinganeni okuthambekele ku-monomer, ngakho isipekthramu yayo ichaza kahle isampula enokugxila okuncishisiwe kodwa ayichazi kahle ingxube egxilile yokuqala. Ukubala isipekthramu yengxube yokuqala ngokuphindaphinda izilinganiso zokumunca ukuze zikhuphuke kubuyisela isilinganiso sengqikithi kadayi kuphela uma ukulinganisa sekuvele kulubhekele lolu shintsho. Akukaze kubuyisele ukuma kwebhande kwasekuqaleni. Noma ubani oqhathanisa isipekthramu yengxube egxilile nenkomba engxube yayo engagxilile uqhathanisa izingxube ezimbili ezihlukile.

Ubude bendlela yokukhanya buyingxenye yomphumela

Isilinganiso sokumunca sikhula ngokuhambisana nebanga elihanjwa ukukhanya ngaphakathi kwesampula. I-cuvette engu-10 mm inikeza isilinganiso sokumunca esiphindwe kashumi kunese-cuvette engu-1 mm equkethe ingxube efanayo. Lokho kulingana kunembile kuphela uma kuyingxube efanayo, futhi ukuhlangana kwenza lo mbandela ubaluleke kakhulu.

Empeleni, ubude bendlela yokukhanya buyithuluzi lokuhlala ngaphakathi kwebanga elisebenzayo. Indlela ende yenza kube lula ukuthola izilinganiso ezingxubeni ezingagxilile, eziningi zazo ezingama-monomer. Indlela emfushane igcina isampula egxilile ngaphakathi kwebanga lokulinganisa ngaphandle kwesinyathelo esikhulu sokunciphisa ukugxila esingashintsha ukulingana. Uhlelo locwaningo lokuhlangana olwaveza amanani angenhla lwenza kona lokhu: amaseli angu-1 centimeter kudayi osukela ku-1.1 kuya ku-34 micromolar, namaseli angu-0.01 centimeter kusukela ku-94 micromolar kuya ku-3.4 millimolar. Izisekelo zokukala imiqulu emincane kakhulu nezifundi zamapuleti zengeza ukwakheka kwazo, okunezindlela ezimfushane futhi ngezinye izikhathi ezishintshashintshayo, kanye nezindawo lapho udayi onenkokhiso evumayo ungabambelela khona. Bika ubude bendlela kanye nenani, ngendlela efanayo naleyo inkomba yesipekthramu ebika ngayo isincibilikisi nosawoti. Isilinganiso sokumunca esingenabo ubude bendlela yokukhanya asiwona umphumela. Siyinzwabethi.

Ukuqikelela ekukaleni kulandela kule ndlela yokusebenza. Vumela amasampula afike ezingeni lokushisa elifanayo ngaphambi kokufunda izilinganiso. Sebenzisa uhlobo olufanayo lwe-cuvette nokuma okufanayo, izingxube eziyizinkomba ezingenadayi eziqukethe usawoti ne-buffer efanayo, nezitsha zengilazi ezihlanzekile, ngoba i-methylene blue ibambelela engilazini nasepulasitikini, kanti i-cuvette enamabala igcina umkhondo wesampula yokugcina egxilile. Funda izilinganiso ngokushesha ngemva kokulungiselela lapho isivinini sokuhlangana sibalulekile, futhi wakhe ijika ngalinye lokulinganisa engxubeni yezinye izakhi efanayo nangobude bendlela obufanayo namasampula angaziwa. Ekuhloleni ngamehlo, khumbula ukuthi iso alisona isikali esihle sesipekthramu. Ukuthi umbala wengxube ungafakazela yini ubumsulwa kuwumbuzo ohlukile onempendulo ethi cha, futhi ukushintsha komthunzi ngenxa yokuhlangana kungesinye sezizathu.

Umdwebo ongawugcina eduze kwethuluzi

Umdwebo ongezansi ufinyeza lesi sihloko ube yinkomba eyodwa yasetafuleni lomsebenzi. Izingxube ezintathu zinodayi ofanayo kodwa zihlukile ngokugxila okuphelele nangosawoti okhona. Izipekthramu zazo ezibonisiwe zikhombisa ibhande le-monomer lobude begagasi obude lilahlekelwa ingxenye yalo iye ebhandeni le-dimer lobude begagasi obufushane njengoba ukunqwabelana kwanda. Izimo zibhalwe emdwebeni ngoba ngaphandle kwazo amajika awakwazi ukusetshenziswa kabusha. Ukuze uthole izindawo zamabhande ezikaliwe ngaphansi kwezimo ezishiwo, sebenzisa inkomba yesipekthramu. Ukuze uthole ukuthi udayi ungena kanjani kumaseli lapho ususengxubeni encibilikile, bheka ukungena kumaseli ngokuncishiswa kwamakhemikhali nokusatshalaliswa phakathi kwezindawo. Ukuze uthole ukuthi inani lokukhanya nokuhleleka kwezilinganiso kuyithinta kanjani imiphumela yokusabela kwamakhemikhali okubangelwa ukukhanya, bheka ukuchayeka ekukhanyeni nokuhleleka kokukala.

Umthetho okufanele uwukhumbule unezingxenye ezimbili. Isipekthramu sihlonza ingxube ekhona ku-cuvette ngaphansi kwezimo ezishiwo. Ukulinganisa okwakhiwe ngaphansi kwalezo zimo ezifanayo kuphela okuguqula isilinganiso sokumunca sibe ukugxila okuphelele.