Nyob rau hauv tsab xov xwm no peb yuav txiav txim siab nthuav dav cov kev tshuaj ntsuam xyuas uas yog raws li kev hloov pauv lub zog ntawm tus kheej atoms. Cov no yog optical txoj kev tsom xam. Cia peb piav qhia txhua tus ntawm lawv, qhia txog cov yam ntxwv tshwj xeeb.
Definition
Txoj kev kho qhov muag ntawm kev tshuaj xyuas - txheej txheej txheej txheem raws li kev hloov pauv lub zog ntawm tus kheej atoms. Lawv lub npe thib ob yog atomic spectroscopy.
Txoj kev kho qhov muag ntawm kev tshuaj xyuas yuav txawv ntawm txoj kev tau txais thiab sau ntxiv cov teeb liab (yuav tsum tau tshuaj xyuas). Cov ntawv luv OMA kuj tseem siv los xaiv lawv. Optical txoj kev tsom xam yog siv los kawm txog lub zog ntws ntawm valence, sab nraud electrons. Feem ntau rau tag nrho lawv cov kev sib txawv yog qhov xav tau ua ntej decomposition rau hauv atoms (atomization) ntawm cov tshuaj ntsuam xyuas.
Txoj kev ntawm txoj kev
Peb twb paub lawm tias qhov twg yog txoj kev kho qhov muag ntawm kev tsom xam. Xav txog tam sim no ntau yam ntawm cov txheej txheem no:
- Refractometrictsom xam.
- kev tshuaj ntsuam polarimetric.
- A set of optical absorption method.
Peb yuav tshuaj xyuas txhua txoj haujlwm ntawm qhov kev faib tawm ntawm cov txheej txheem kho qhov muag ntawm kev tshuaj xyuas ntxiv cais.
Refractometric ntau yam
qhov ntsuas qhov ntsuas tsis pom qhov twg? Hom kev tsom xam ntawm optical-spectral no yog siv dav hauv kev kawm txog cov khoom noj khoom haus - rog, txiv lws suav, ntau yam kua txiv hmab txiv ntoo, jam, jam.
Refractive tsom xam yog ua raws li kev ntsuas qhov ntsuas qhov taw qhia (lwm lub npe yog refraction), uas tuaj yeem siv los txiav txim siab qhov xwm txheej ntawm ib yam khoom, nws cov purity thiab feem pua ntawm cov kev daws teeb meem loj.
Refraction ntawm lub teeb beam yuav ib txwm tshwm sim ntawm ciam teb ntawm ob qhov sib txawv, yog tias lawv muaj qhov sib txawv. Qhov piv ntawm lub sine ntawm lub kaum sab xis ntawm qhov tshwm sim rau lub sine ntawm lub kaum sab xis ntawm refraction yuav yog tus txheeb ze refractive index ntawm cov khoom thib ob rau thawj. Tus nqi no suav tias yog tas mus li.
Qhov ntsuas ntawm qhov cuam tshuam yog nyob ntawm dab tsi? Ua ntej tshaj plaws, los ntawm qhov xwm txheej. Lub teeb wavelength thiab kub kuj tseem ceeb ntawm no.
Yog lub kaum sab xis ntawm lub teeb poob ntawm 90 degrees, txoj hauj lwm no yuav raug suav hais tias yog lub kaum sab xis ntawm refraction. Nws tus nqi tsuas yog nyob ntawm qhov ntsuas ntawm cov xov xwm uas lub teeb dhau mus. Nws muab dab tsi? Yog tias qhov ntsuas pom ntawm thawj qhov nruab nrab qhib rau tus kws tshawb fawb, tom qab ntsuas qhov txwv lub kaum sab xis ntawm qhov cuam tshuam ntawm qhov thib ob, nws tuaj yeem txiav txim siab qhov ntsuas qhov nruab nrab ntawm qhov nruab nrab uas twb muaj kev txaus siab rau nws.
Polarimetric ntau yam
Peb txuas ntxiv txheeb xyuas cov hauv paus ntawm kev kho qhov muag ntawm kev tsom xam. Polarimetric yog raws li cov cuab yeej ntawm qee yam khoom siv los hloov cov vector ntawm lub teeb oscillations.
Cov khoom uas muaj cov cuab yeej zoo kawg no, thaum lub teeb polarized hla lawv, hu ua optically active. Piv txwv li, cov yam ntxwv ntawm cov qauv ntawm cov molecules ntawm tag nrho cov khoom qab zib txiav txim siab qhov tshwm sim ntawm kev ua haujlwm kho qhov muag hauv ntau yam kev daws teeb meem.
Ib txoj kab polarized tau dhau los ntawm txheej txheej ntawm cov tshuaj zoo li no. Cov kev taw qhia ntawm oscillation yuav raug hloov - lub dav hlau ntawm polarization vim qhov no yuav tig los ntawm ib lub kaum ntse ntse. Nws yuav raug hu ua lub kaum sab xis ntawm kev sib hloov ntawm lub dav hlau ntawm polarization. Txoj hauj lwm no nyob ntawm tus lej hauv qab no:
- Kev sib hloov ntawm lub dav hlau ntawm polarization.
- Thickness thiab concentration ntawm cov txheej txheem ntawm cov tshuaj.
- Lub wavelength ntawm lub teeb polarized tshaj plaws.
- Kub.
Qhov ntom ntom ntom ntom ntawm cov khoom hauv qhov no yuav ua rau muaj kev sib hloov tshwj xeeb. Tus nqi no yog dab tsi? Nws yog to taub raws li lub kaum sab xis ntawm lub dav hlau ntawm polarization rotates thaum ib tug polarized beam hla los ntawm kev daws. Cov txiaj ntsig hauv qab no raug lees txais:
- 1 ml daws.
- 1 g ntawm cov tshuaj yaj hauv qhov ntim ntawm cov tshuaj no.
- Lub thickness ntawm txheej txheej (los yog qhov ntev ntawm lub polarizing raj) yog 1 dm.
Optical absorptionntau yam
Peb tau paub txuas ntxiv nrog cov txheej txheem kho qhov muag ntawm kev tshuaj xyuas hauv kev tshuaj ntsuam chemistry. Cov qeb tom ntej hauv kev faib tawm yog kho qhov muag nqus.
Qhov no suav nrog cov txheej txheem ntawm kev tshuaj xyuas uas yog raws li kev nqus ntawm electromagnetic radiation los ntawm cov tshuaj ntsuam xyuas. Lawv raug suav hais tias niaj hnub no feem ntau hauv kev tshawb fawb, kev tshawb fawb, chaw soj nstuam ntawv pov thawj.
Thaum lub teeb yog nqus, cov molecules thiab atoms ntawm absorbing tshuaj yuav dhau mus rau hauv lub xeev tshiab zoo siab. Twb tau, nyob ntawm ntau yam ntawm cov khoom zoo li no, nrog rau kev muaj peev xwm los hloov lub zog absorbed los ntawm lawv, tag nrho cov txheej txheem ntawm absorbing optical txoj kev yog txawv. Peb yuav nthuav qhia lawv kom ntxaws ntxiv nyob rau hauv kab ntawv txuas ntxiv.
Kev faib tawm ntawm cov txheej txheem kho qhov muag
Peb coj los rau koj mloog qhov kev faib tawm ntawm cov txheej txheem ntawm kev tshuaj xyuas qhov muag hauv chemistry. Nws yog sawv cev los ntawm plaub txoj haujlwm:
- Atomic nqus. Dab tsi suav nrog ntawm no? Qhov no yog ib qho kev soj ntsuam raws li kev nqus ntawm lub teeb lub zog los ntawm cov atoms ntawm cov khoom nyob rau hauv kev kawm.
- Absorptive molecular. Txoj kev no yog ua raws li kev nqus ntawm lub teeb los ntawm cov ions nyuaj thiab cov molecules ntawm kev kawm, tshuaj xyuas cov khoom. Kev saib xyuas ntau yog them rau ntawm no rau thaj chaw infrared, pom thiab ultraviolet zones ntawm spectrum. Raws li, cov no yog photocolorimetry, spectrophotometric, IR spectroscopy. Dab tsi yog qhov tseem ceeb rau qhov tseem ceeb ntawm no? Spectrophotometry thiab photocolorimetry yog nyob ntawm kev sib cuam tshuam ntawm hluav taws xob nrog ntau lub tshuab homogeneous. Yog li ntawd, hauvNyob rau hauv analytical chemistry, lawv feem ntau ua ke rau hauv ib pawg - cov txheej txheem photometric.
- Nephelometry. Hom kev tshuaj ntsuam no yog ua raws li kev nqus thiab kev tawg ntxiv ntawm lub teeb hluav taws xob los ntawm kev tshem tawm cov khoom hauv kev kawm.
- Fluorometric (los yog luminescent) tsom xam. Cov txheej txheem yog ua raws li kev ntsuas hluav taws xob uas tshwm sim thaum lub zog tso tawm los ntawm cov khoom zoo siab ntawm cov tshuaj uas tau kawm los ntawm tus kws tshawb fawb. Sawv cev los ntawm fluorescence thiab phosphorescence. Peb yuav tshuaj xyuas lawv nyias.
Luminescence
Luminescence feem ntau nyob rau hauv lub ntiaj teb kev tshawb fawb yog hu ua lub ci ntawm atoms, molecules, ions thiab lwm yam nyuaj particles thiab compounds ntawm teeb meem. Nws tshwm sim los ntawm kev hloov ntawm electrons mus rau lub xeev ib txwm los ntawm lub xeev zoo siab.
Yog li, txhawm rau kom cov khoom pib luminesce, qee lub zog yuav tsum tau muab rau nws los ntawm sab nraud. Cov ntsiab lus ntawm cov khoom nyob rau hauv kev kawm yuav nqus lub zog, dhau mus rau hauv lub xeev zoo siab, uas lawv yuav nyob twj ywm rau ib lub sijhawm. Tom qab ntawd rov qab mus rau yav dhau los lub xeev ntawm so, thaum muab ib feem ntawm nws tus kheej lub zog nyob rau hauv daim ntawv ntawm luminescence quanta.
Phosphorescence thiab fluorescence
Nyob ntawm lub xeev zoo siab, nrog rau lub sijhawm nyob ntawm cov khoom hauv nws, muaj ob hom luminescence - phosphorescence thiab fluorescence. Txhua tus sawv cev rau nws cov yam ntxwv tshwj xeeb:
- Fluorescence. Ib hom self-luminescence ntawm ib yam khoom, uasyuav txuas ntxiv thaum irradiated. Thaum tus kws tshawb fawb tshem tawm qhov kev zoo siab, lub ci yuav nres tam sim ntawd lossis tom qab 0.001 vib nas this.
- Phosphorescence. Ib yam ntawm nws tus kheej-luminescence ntawm ib yam khoom uas yuav mus ntxiv txawm tias thaum lub teeb uas excites nws yog muab tua.
Nws yog phosphorescence uas yog siv los kawm cov khoom noj. Txoj kev tshawb fawb luminescent pab kom pom cov khoom hauv cov qauv kawm ntawm nws qhov concentration ntawm 10- 11 g / g. Txoj kev no yuav zoo rau kev txiav txim siab qee yam ntawm cov vitamins, muaj cov proteins thiab cov rog hauv cov khoom noj siv mis, kawm txog cov khoom tshiab ntawm cov nqaij thiab ntses, kuaj xyuas kev puas tsuaj rau cov txiv hmab txiv ntoo, zaub, thiab berries. Tsis tas li, kev tshawb fawb luminescent yog siv los txheeb xyuas cov tshuaj suav nrog, tshuaj tua kab, tshuaj tua kab, thiab ntau yam carcinogenic hauv cov khoom.
Tag nrho pab pawg nqus tau feem ntau ua ke rau hauv spectrochemical (lossis spectroscopic) qeb hauv kev faib tawm ntawm cov txheej txheem kho qhov muag ntawm kev tshuaj xyuas hauv analytical chemistry. Txawm tias muaj tseeb hais tias cov txheej txheem yog inherently txawv, lawv tag nrho cov muaj ib yam uas zoo sib xws: lawv yog raws li tib txoj cai ntawm lub teeb haum. Tab sis tib lub sijhawm, muaj qhov sib txawv tseem ceeb hauv hom absorbing hais, kev tsim kho vajtse ntawm kev kawm, thiab lwm yam.
Photometric ntau yam
Lub npe ntawm cov txheej txheem ntawm spectral molecular absorption tsom xam. Lawv yog raws li kev xaiv haumelectromagnetic hluav taws xob nyob rau hauv pom, ultraviolet, infrared cheeb tsam los ntawm cov molecules ntawm cov tivthaiv nyob rau hauv kev kawm. Nws cov concentration yog txiav txim los ntawm tus kws tshaj lij raws li txoj cai Bouguer-Lambert-Beer.
Kev tshuaj ntsuam duab muaj xws li photometry, spectrophotometric thiab photocolorimetry.
Photoelectrocolorimetric ntau yam
Txoj kev photoelectrocolorimetric yog lub hom phiaj ntau dua thaum piv rau qhov pom qhov muag xim. Raws li, nws muab cov txiaj ntsig kev tshawb fawb tseeb dua. Ntau FECs tau siv ntawm no - photoelectric colorimeters.
Lub luminous flux thaum dhau los ntawm cov kua xim xim yog ib nrab nqus. Tus so ntawm nws ntog rau ntawm lub photocell, qhov twg ib tug hluav taws xob tam sim no tshwm sim, uas registers ib ammeter. Qhov siab dua qhov concentration ntawm cov tshuaj, qhov ntau dua nws cov optical ntom. Qhov ntau dua qhov nqus ntawm lub teeb thiab lub zog me dua ntawm qhov tshwm sim photocurrent.
Peb tau tshuaj xyuas tag nrho cov kev faib tawm ntawm kev tshuaj xyuas qhov muag siv niaj hnub no hauv kev tshuaj ntsuam chemistry: refractometric, polarimetric, optical absorption. Lawv koom ua ke los ntawm qhov xav tau ua ntej atomization ntawm cov khoom. Tab sis tib lub sijhawm, txhua txoj hauv kev yog qhov txawv los ntawm nws cov yam ntxwv tshwj xeeb - ntau yam ntawm kev txais thiab sau npe lub teeb liab rau kev tshuaj xyuas.
