Fluorescence Spectroscopy yog dab tsi?
Fluorescence spectroscopy soj ntsuam cov fluorescence ntawm molecules raws li lawv cov khoom fluorescent.
Fluorescence yog lub luminescence uas tshwm sim thaum lub molecule zoo siab los ntawm ib tug photon mus rau ib qho hluav taws xob zoo siab lub xeev thiaj li yuav rov qab mus rau hauv av.
Fluorescence spectroscopy siv lub teeb ntawm lub teeb los ua kom cov hluav taws xob zoo siab hauv qee qhov sib xyaw molecules thiab ua rau lawv tawm lub teeb. Lub teeb hla dhau los ntawm monochromator thiab nkag mus rau hauv lub ntsuas ntsuas qhov twg nws tau kuaj pom, uas yog siv los ntsuas thiab txheeb xyuas cov molecules lossis hloov pauv hauv cov molecules.
Taw qhia rau Fluorescence Steady-State Spectroscopy thiab Kev Ntsuas Lub Neej
Fluorescence dav hais txog qhov tshwm sim ntawm luminescence, lub teeb tawm los ntawm cov molecules. Muaj ob peb hom glow.
Photoluminescence yog lub emission ntawm photons txaus siab los ntawm lub teeb lub zog los yog photons.
Chemiluminescence, txhais raws li lub luminescence ntawm photons txaus siab los ntawm cov tshuaj zog, muaj xws li bioluminescence, raws li pom nyob rau hauv fireflies thiab ntau marine lub neej.
Electroluminescence yog qhov emission ntawm photons thaum hluav taws xob hluav taws xob los yog lub zog hluav taws xob muaj zog txhawb nqa photons, xws li hauv qee qhov kev siv teeb pom kev zoo.
Tshwj xeeb, fluorescence yog ib hom photoluminescence qhov twg lub teeb tso electrons nyob rau hauv lub xeev zoo siab. Lub xeev zoo siab sai poob thermal zog rau ib puag ncig los ntawm kev co, thiab tom qab ntawd emits photons los ntawm qis tshaj singlet zoo siab lub xeev. Cov txheej txheem photon emission no sib tw nrog lwm cov txheej txheem tsis muaj hluav taws xob, suav nrog kev hloov hluav taws xob thiab hluav taws xob poob.
Thaum siv lo lus "fluorescence", tib txoj kev ntsuas feem ntau siv rau ib qho ntawm cov chav kawm saum toj no ntawm luminescence.
Fluorescence Spectroscopy yog dab tsi?
Fluorescence excitation thiab emission spectra mirroring ib leeg. Fluorescence spectroscopy siv emission thiab excitation kom pom tias tus qauv hloov pauv li cas.
Daim duab 1: Ib qho fluorescence excitation spectrum (xiav) thiab ib qho emission spectrum (ntsuab) yog daim iav duab ntawm ib leeg.
Steady-state fluorescence spectroscopy yog thaum lub molecule fluoresces thaum zoo siab los ntawm lub teeb qhov chaw tas li, thiab cov emission photons los yog siv tau raug kuaj pom raws li kev ua haujlwm ntawm wavelength. Fluorescence emission spectrum yog thaum lub excitation wavelength yog tsau, lub emission wavelength scanned, thiab kev sib raug zoo ntawm kev siv thiab lub emission wavelength tau txais.
Lub fluorescence excitation spectrum yog thaum lub emission wavelength tsau, los ntawm kev hloov lub excitation monochromator wavelength, luam theej qhov siv ntawm txawv wavelengths. Nyob rau hauv txoj kev no, lub spectrum muab cov ntaub ntawv hais txog tus qauv thiab nqus wavelengths los xaiv qhov zoo tshaj plaws emission wavelength rau kev kuaj pom ntawm emission. Nws zoo ib yam li absorption spectroscopy, tab sis yog cov txheej txheem rhiab dua nyob rau hauv cov nqe lus ntawm kev kuaj pom qhov txwv thiab qhov tshwj xeeb molecular. Excitation spectra yog tshwj xeeb rau ib qho emission wavelength / hom, txheeb ze rau qhov nqus spectra ntawm txhua hom absorbing nyob rau hauv kev ntsuas los yog qauv. Lub emission thiab excitation spectra ntawm ib tug muab fluorophore yog daim iav duab ntawm ib leeg. Feem ntau, emission spectra tshwm nyob rau ntawm lub wavelengths siab dua (qis zog) dua li excitation lossis absorption spectra
Ob hom spectral no (emission thiab excitation) yog siv los soj ntsuam seb tus qauv hloov pauv li cas. Qhov kev siv lub spectral thiab lub ncov wavelength tuaj yeem sib txawv nrog qhov sib txawv xws li qhov kub, qhov siab, lossis kev cuam tshuam nrog cov molecules nyob ib puag ncig. Qhov no suav nrog quenching molecules thiab molecules lossis cov ntaub ntawv koom nrog hauv kev hloov hluav taws xob. Qee cov fluorophores tau nkag siab rau cov khoom ntawm qhov hnyav ib puag ncig, xws li pH, polarity, thiab qee qhov ionic concentrations.
Hom molecules lossis cov ntaub ntawv twg muaj fluorescence?
Fluorescence emission spectra ntawm qee yam fluorophores. Fluorophores ua lub luag haujlwm tseem ceeb hauv fluorescence spectroscopy thiab ua rau hom spectroscopy no yog cov txheej txheem rhiab heev.
Daim duab 2: Fluorescence emission spectra ntawm qee cov fluorophores thoob plaws UV thiab pom spectrum
Fluorescent molecules thiab cov ntaub ntawv tuaj nyob rau hauv tag nrho cov duab thiab ntau thiab tsawg. Qee qhov muaj fluorescent, xws li chlorophyll thiab cov amino acid residues tryptophan (Trp), phenylalanine (Phe) thiab tyrosine (Tyr). Lwm tus yog cov molecules synthesized li ruaj khov organic dyes lossis cov cim npe uas tuaj yeem muab ntxiv rau lwm lub tshuab tsis muaj fluorescent. Feem ntau, cov organic fluorescent molecules muaj cov yam ntxwv xws li cov nplhaib uas muaj ntxhiab thiab π-conjugated electrons. Nyob ntawm lawv qhov loj thiab cov qauv, cov organic dyes emit lub teeb nyob rau hauv wavelengths xws li ultraviolet mus rau ze-infrared.
Hauv qab no yog qee qhov sib txawv fluorophores uas nws cov emission tuaj yeem pom nyob rau ntawm UV-Vis ntau yam. Rau qee lub ntiaj teb tsis tshua muaj cov ntsiab lus, xws li lanthanides, vim yog cov khoom siv hluav taws xob ntau dua, kev hloov hluav taws xob vim yog kev hloov pauv ntawm cov hlau ligands tshwm sim ntawm 4f-5d lossis txawm 4f-4f orbitals. (Bunzli, 1989) Muaj ntau lub molecules uas emit lub teeb nyob rau hauv cov xwm, xws li ib co amino acids, chlorophyll thiab ntuj pigments. Tseem muaj lwm tus tau ua tib zoo tsim los siv tshwj xeeb hauv fluorescence spectroscopy
Piv txwv ntawm fluorescent molecules thiab cov ntaub ntawv:
Amino acids (Trp, Phe, Tyr)
Base khub derivatives (2-AP, 3-MI, 6-MI, 6-MAP, pyrrole-c, tC)
tshuaj chlorophyll
Fluorescent proteins (FPs)
Organic dyes (fluorescein, rhodamine, n-aminocoumarins thiab lawv cov derivatives)
Rare Earth Elements (Lanthanides)
semiconductor
quantum dots
ib leeg-walled carbon nanotubes
Hnub ci roj teeb
Pigment, Electroplating
phosphor
Ntau…
Lwm cov molecules thiab cov ntaub ntawv xws li fluorescent proteins, semiconductors, phosphors, thiab lub ntiaj teb tsis tshua muaj cov ntsiab lus feem ntau siv cov qauv fluorescent. Polymers uas muaj conjugated aromatic hydrocarbons los yog dienes feem ntau kuj muaj fluorescent zog. Tau kawg, cov kws tshawb fawb kuj tau ua haujlwm ntawm kev tsim cov ntaub ntawv tshiab.
