1489:
1501:
544:
336:
658:
320:(the values of the molar absorption coefficient for each species at these wavelengths must also be known). The wavelengths chosen are usually the wavelengths of maximum absorption (absorbance maxima) for the individual species. None of the wavelengths may be an
304:
539:{\displaystyle {\begin{cases}A(\lambda _{1})=\ell \sum _{i=1}^{N}\varepsilon _{i}(\lambda _{1})c_{i},\\\ldots \\A(\lambda _{N})=\ell \sum _{i=1}^{N}\varepsilon _{i}(\lambda _{N})c_{i}.\\\end{cases}}}
569:
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97:
of a material that has only one absorbing species also depends on the pathlength and the concentration of the species, according to the
73:). In older literature, the cm/mol is sometimes used; 1 Mâ‹…cm equals 1000 cm/mol. The molar absorption coefficient is also known as the
1411:
1163:
979:
907:
1532:
1416:
1234:
188:(ln). The molar absorption coefficient is usually decadic. When ambiguity exists, it is important to indicate which one applies.
1431:
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1158:
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52:
653:{\displaystyle \sigma =\ln(10){\frac {10^{3}}{N_{\text{A}}}}\varepsilon \approx 3.82353216\times 10^{-21}\,\varepsilon .}
1292:
1139:
1028:
1448:
923:
Gill, S. C.; von Hippel, P. H. (1989). "Calculation of protein extinction coefficients from amino acid sequence data".
1287:
1256:
1189:
765:
If the molar absorption coefficient is known, it can be used to determine the concentration of a protein in solution.
669:
1438:
1380:
1229:
1101:
195:
absorbing species in a solution, the overall absorbance is the sum of the absorbances for each individual species
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is decadic (10-based) or
Napierian (e-based), i.e., defined with respect to the transmission via
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554:
185:
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36:
786:"Chapter 11 Section 2 - Terms and symbols used in photochemistry and in light scattering"
1521:
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1002:
735:
299:{\displaystyle A=\sum _{i=1}^{N}A_{i}=\ell \sum _{i=1}^{N}\varepsilon _{i}c_{i}.}
839:
810:
751:
56:
747:
673:
549:
The molar absorption coefficient (in units of Mcm) is directly related to the
317:
173:
94:
44:
16:
Measure of how strongly a chemical species absorbs a given wavelength of light
843:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
814:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
852:
823:
746:
depends almost exclusively on the number of aromatic residues, particularly
40:
20:
944:
739:
81:, but the use of these alternative terms has been discouraged by the
330:
can be solved to find the concentrations of each absorbing species:
63:), but in practice, quantities are usually expressed in terms of
975:
971:
172:
Different disciplines have different conventions as to whether
313:
absorbing species can be found by measuring the absorbance at
672:
is equal to the molar absorption coefficient divided by the
532:
69:â‹…cm or Lâ‹…molâ‹…cm (the latter two units are both equal to
55:
of molar absorption coefficient is the square metre per
962:
Nikon
MicroscopyU: Introduction to Fluorescent Proteins
964:
includes a table of molar attenuation coefficient of
572:
339:
208:
109:
1457:
1394:
1353:
1346:
1308:
1280:
1222:
1172:
1072:
1009:
793:
Compendium on
Analytical Nomenclature (Orange Book)
652:
538:
298:
130:
754:. Similarly, the molar absorption coefficient of
902:(3rd ed.). New York: Springer. p. 59.
762:can be predicted given the nucleotide sequence.
326:for a pair of species. The set of the following
987:
8:
1059:Vibrational spectroscopy of linear molecules
780:
778:
750:, and can be predicted from the sequence of
1350:
1054:Nuclear resonance vibrational spectroscopy
994:
980:
972:
1427:Inelastic electron tunneling spectroscopy
1107:Resonance-enhanced multiphoton ionization
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1195:Extended X-ray absorption fine structure
738:, the molar absorption coefficient of a
900:Principles of Fluorescence Spectroscopy
774:
885:Compendium on Analytical Nomenclature
872:Compendium on Analytical Nomenclature
725:= Molar mass of the absorbing species
131:{\displaystyle A=\varepsilon c\ell ,}
35:) is a measurement of how strongly a
7:
1500:
840:Compendium of Chemical Terminology
811:Compendium of Chemical Terminology
14:
1412:Deep-level transient spectroscopy
1164:Saturated absorption spectroscopy
1499:
1488:
1487:
1417:Dual-polarization interferometry
309:The composition of a mixture of
1432:Scanning tunneling spectroscopy
1407:Circular dichroism spectroscopy
1402:Acoustic resonance spectroscopy
1361:Fourier-transform spectroscopy
1049:Vibrational circular dichroism
719:= Molar absorption coefficient
591:
585:
513:
500:
460:
447:
417:
404:
364:
351:
1:
1159:Cavity ring-down spectroscopy
1064:Thermal infrared spectroscopy
713:= Mass absorption coefficient
65:
29:molar attenuation coefficient
1293:Inelastic neutron scattering
937:10.1016/0003-2697(89)90602-7
150:molar absorption coefficient
75:molar extinction coefficient
25:molar absorption coefficient
1354:Data collection, processing
1230:Photoelectron/photoemission
670:mass absorption coefficient
664:Mass absorption coefficient
1554:
1439:Photoacoustic spectroscopy
1381:Time-resolved spectroscopy
795:. IUPAC. 2002. p. 28.
676:of the absorbing species.
1483:
1465:Astronomical spectroscopy
1444:Photothermal spectroscopy
553:(in units of cm) via the
551:attenuation cross section
898:Lakowicz, J. R. (2006).
865:"Molecular Spectroscopy"
1533:Absorption spectroscopy
1449:Pump–probe spectroscopy
1338:Ferromagnetic resonance
1130:Laser-induced breakdown
925:Analytical Biochemistry
853:10.1351/goldbook.A00044
824:10.1351/goldbook.E02293
1145:Glow-discharge optical
1125:Raman optical activity
1039:Rotational–vibrational
878:"Measuring techniques"
654:
540:
489:
393:
328:simultaneous equations
300:
272:
235:
132:
1366:Hyperspectral imaging
655:
541:
469:
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301:
252:
215:
133:
39:absorbs, and thereby
1528:Analytical chemistry
1118:Coherent anti-Stokes
1073:UV–Vis–NIR "Optical"
966:fluorescent proteins
570:
337:
206:
107:
51:of the species. The
1422:Hadron spectroscopy
1212:Conversion electron
1173:X-ray and Gamma ray
1080:Ultraviolet–visible
168:is the path length.
160:molar concentration
43:, light at a given
1470:Force spectroscopy
1395:Measured phenomena
1386:Video spectroscopy
1090:Cold vapour atomic
650:
536:
531:
296:
128:
79:molar absorptivity
49:intrinsic property
1515:
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1479:
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1371:Spectrophotometry
1298:Neutron spin echo
1272:Beta spectroscopy
1185:Energy-dispersive
616:
613:
555:Avogadro constant
186:natural logarithm
162:of those species;
152:of that material;
1545:
1538:Molar quantities
1503:
1502:
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1262:phenomenological
1011:Vibrational (IR)
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99:Beer–Lambert law
89:Beer–Lambert law
72:
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37:chemical species
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956:External links
954:
951:
950:
931:(2): 319–326.
915:
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887:. IUPAC. 2002.
874:. IUPAC. 2002.
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1102:Near-infrared
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909:9780387312781
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756:nucleic acids
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38:
30:
26:
22:
1504:
1492:
1472:(a misnomer)
1458:Applications
1376:Time-stretch
1267:paramagnetic
1085:Fluorescence
1003:Spectroscopy
928:
924:
918:
899:
893:
884:
871:
859:
845:Absorptivity
838:
830:
809:
801:
792:
764:
736:biochemistry
733:
702:
667:
557:
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321:
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171:
149:
140:
92:
78:
74:
28:
24:
18:
1044:Vibrational
752:amino acids
318:wavelengths
47:. It is an
1522:Categories
1250:Two-photon
1152:absorption
1034:Rotational
816:Extinction
769:References
748:tryptophan
674:molar mass
625:3.82353216
174:absorbance
95:absorbance
45:wavelength
41:attenuates
1328:Terahertz
1309:Radiowave
1207:Mössbauer
645:ε
636:−
628:×
622:≈
619:ε
583:
574:σ
505:λ
492:ε
471:∑
467:ℓ
452:λ
438:…
409:λ
396:ε
375:∑
371:ℓ
356:λ
275:ε
254:∑
250:ℓ
217:∑
123:ℓ
117:ε
71:0.1 m/mol
21:chemistry
1494:Category
1223:Electron
1190:Emission
1140:emission
1097:Vibronic
730:Proteins
1506:Commons
1333:ESR/EPR
1281:Nucleon
1109:(REMPI)
945:2610349
740:protein
693:⁄
184:) or a
158:is the
148:is the
53:SI unit
1347:Others
1135:Atomic
943:
906:
760:260 nm
744:280 nm
703:where
141:where
23:, the
1288:Alpha
1257:Auger
1235:X-ray
1202:Gamma
1180:X-ray
1113:Raman
1024:Raman
1019:FT-IR
881:(PDF)
868:(PDF)
835:IUPAC
806:IUPAC
789:(PDF)
83:IUPAC
61:m/mol
941:PMID
904:ISBN
668:The
180:(log
93:The
77:and
57:mole
1316:NMR
933:doi
929:182
849:doi
847:".
820:doi
818:".
758:at
742:at
734:In
27:or
19:In
1524::
1321:2D
1240:UV
939:.
927:.
883:.
870:.
837:,
808:,
791:.
777:^
686:=
639:21
632:10
598:10
589:10
580:ln
563::
199::
182:10
85:.
995:e
988:t
981:v
968:.
947:.
935::
912:.
851::
822::
723:M
717:ε
710:m
708:ε
696:M
690:ε
683:m
681:ε
648:.
612:A
608:N
602:3
592:)
586:(
577:=
561:A
558:N
527:.
522:i
518:c
514:)
509:N
501:(
496:i
486:N
481:1
478:=
475:i
464:=
461:)
456:N
448:(
445:A
431:,
426:i
422:c
418:)
413:1
405:(
400:i
390:N
385:1
382:=
379:i
368:=
365:)
360:1
352:(
349:A
343:{
315:N
311:N
294:.
289:i
285:c
279:i
269:N
264:1
261:=
258:i
247:=
242:i
238:A
232:N
227:1
224:=
221:i
213:=
210:A
197:i
193:N
166:â„“
156:c
146:ε
126:,
120:c
114:=
111:A
66:M
59:(
33:ε
31:(
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