Qhov txawv ntawm Kev nqus thiab xa tawm

2024 Tus sau: Alex Aldridge | [email protected]. Kawg hloov kho: 2023-12-17 13:40

Absorbance vs Transmittance

Kev nqus thiab xa tawm yog ob lub ntsiab lus tseem ceeb uas tau tham hauv spectrometry thiab analytical chemistry. Absorbance tuaj yeem raug txheeb xyuas raws li tus nqi ntawm lub teeb uas yog absorbed los ntawm ib qho piv txwv. Kev xa tawm tuaj yeem lees paub raws li tus nqi ntawm lub teeb dhau los ntawm tus qauv ntawd. Ob qho tib si ntawm cov ntsiab lus no tseem ceeb heev hauv cov haujlwm xws li kev tshuaj ntsuam chemistry, spectrometry, quantitative and qualitative analysis, physics thiab ntau yam hauj lwm. Nws yog ib qho tseem ceeb kom muaj kev nkag siab zoo nyob rau hauv cov ntsiab lus ntawm absorbance thiab transmittance thiaj li ua tau zoo hauv cov teb. Hauv tsab xov xwm no, peb yuav tham txog dab tsi yog absorbance thiab transmittance, lawv cov ntsiab lus, kev siv ntawm absorbance thiab transmittance, qhov zoo sib xws ntawm ob, kev sib txuas ntawm absorbance thiab transmittance, thiab thaum kawg qhov txawv ntawm absorbance thiab transmittance.

Dab tsi yog Absorbance?

Yuav kom nkag siab lub tswv yim ntawm absorbance, ib tug yuav tsum xub nkag siab txog qhov nqus spectrum. Lub atom muaj ib tug nucleus, uas yog ua los ntawm protons thiab neutrons, thiab electrons uas yog orbiting nyob ib ncig ntawm lub nucleus. Lub orbit ntawm lub electron nyob ntawm lub zog ntawm lub electron. Siab dua lub zog ntawm electron, deb ntawm lub nucleus nws yuav orbit. Siv quantum txoj kev xav nws tuaj yeem pom tau tias cov hluav taws xob tsis tuaj yeem tsuas yog tau txais qib zog xwb. Cov hluav taws xob hluav taws xob muaj peev xwm muaj tsis sib xws. Thaum ib qho piv txwv ntawm atoms muab nrog ib tug nruam spectrum nyob rau hauv ib co cheeb tsam, cov electrons nyob rau hauv lub atoms nqus ib tug npaum li cas ntawm lub zog. Txij li thaum lub zog ntawm electromagnetic yoj kuj quantized, nws muaj peev xwm hais tias cov electrons nqus photons nrog ib tug tshwj xeeb energies. Ntawm qhov spectrum coj tom qab lub teeb dhau los ntawm cov khoom siv, qee lub zog zoo li ploj lawm. Cov zog no yog cov photons uas tau nqus los ntawm cov atoms.

Absorbance is defined as Log₁₀ (I₀/I), qhov twg kuv_{0yog qhov kev siv ntawm qhov teeb meem teeb pom kev zoo, thiab kuv yog qhov siv hluav taws xob hluav taws xob uas tau dhau los ntawm cov qauv. Lub teeb hluav taws xob yog monochromatic thiab teem rau ib lub teeb wavelength. Txoj kev no yog siv rau ntawm spectrophotometers. Lub absorbance nyob ntawm qhov concentration ntawm tus qauv thiab qhov ntev ntawm tus qauv.}

Qhov nqus ntawm cov tshuaj yog linearly proportional rau qhov concentration raws li Txoj Cai Beer - Lambert txoj cai, yog tias I_{0 / Kuv tus nqi nyob ntawm 0.2 thiab 0.7. Qhov no yog txoj cai muaj txiaj ntsig zoo hauv spectroscopic txoj kev siv hauv kev txheeb xyuas ntau.}

Thaum absorbance tau txhais hauv thaj chaw uas tsis yog chemistry, nws txhais tau tias Log_e (I_0/I).

Kev xa tawm yog dab tsi?

Kev xa tawm yog qhov sib txawv ntawm qhov nqus. Transmittance muab ib qho kev ntsuas ntawm lub teeb uas dhau los ntawm cov qauv. Tus nqi ntsuas nyob rau hauv feem ntau ntawm cov tswv yim spectroscopic txoj kev yog qhov transmittance siv.

Kev siv zog sib faib los ntawm qhov kev siv zog muab qhov kev xa tawm ntawm tus qauv.

Qhov txawv ntawm Transmittance thiab Absorbance yog dab tsi?