Zurstandardisierung der direkten spektrophotometrischen auswertung von chromatogrammen

Treiber, L.; Örtengren, B.; Lindsten, R.; Örtegren, T.

doi:10.1016/s0021-9673(01)80211-9

Cited by 13 publications

(3 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The inhomogeneity caused by tailing or other deformation of chromatographic zones has been countered by some workers by scanning chromatographic zones with a small spot of monochromatic light in a zig-zag fashion (flying spot principle [ 34 ]). Equal success, but with a technically simpler approach, has been reported by Treiber et al [ 35 ], with a two-dimensional scanning approach ( fig. 5 ).…”

Section: Calibrationmentioning

confidence: 73%

See 1 more Smart Citation

Diffuse reflectance spectroscopy; applications, standards, and calibration (with special reference to chromatography)

Frei¹

1976

J. RES. NATL. BUR. STAN. SECT. A.

View full text Add to dashboard Cite

The multitude of areas in which diffuse refl ect ance spectroscopy can b e applied has been described in sever al books and reviews and ra nges fr om color measurements of t extiles, pharmaceuticals, building materials, p aper and pulp materi als et c., to adsorption studies and other basic investigations in physical, inorganic and organic chemistry.The maj or area of application is still the measurement of color which has become indispensible in the quality control of colored products, dyes and pigments. Color m atching practices a nd t echni ques with sophisticated instrumentation which can be fully computerized as well as the use of simpler filter instruments for quality contr ol ar e m entioned.Tran sfera bility of refl ect an ce d at a i.e., color coordinat es, depends on the quality of standa rds particularly when absolute measurements are desired . The difficulty of fi nding suitable "white standards" with good refl ection properties at low UV and with a good long t erm stability is discussed . Similar arguments hold for spher e coatin g m a t eri als. For t he measurement of flu orescing surfaces suitable st andards are lacking which renders transfer of su ch data almost impossible.The usefulness of diffuse r efl ectance t echniques to study adsorption phenomen a on sm all particle a dsorbents is demonstrated with a malachit e green-o-carboxylic acid lactone syst em studied b y Kortum . This or similar syst ems could be ad opted t o the m easurement of r elative surface areas on certain chromatographic adsorbents yielding m ore realistic values than the BET-method .The most r ecent area of applica tion has been in the fiel d of chromatograph y for the in situ evaluation of chromatographic zones in fl a t-bed chromatography, electrophoresis and isoelectric focusing.In chromatography, standardization is less problematic since usu ally r elative measurements ar e suffi cient . On the other hand one has t o find suitable calibration procedures . The use of the Kub elka-Munk function is often questionable since we are usually n ot dealing with layers of infinite thickness and below 300 nm the conventional adsorbents such as silica gel, alumina or cellulose are strongly absorbing. Experiences with a n ew function combining the laws of Kub elka-Munk a nd Lambert-Beer are therefore presented .The problem is also t o find calibration t ec hniques which account for chromat ogra phic paramet ers. Until recentl y it was believed that a quantitative evaluation of chromatogra ms required a number of reference zones t o b e developed on the same chrom at ogra m . In our experience this is n o longer true. A novel calibration technique which utilizes the concept of transferable calibra tion factors is discussed. \¥ ith this approach a quantitative evaluation of a chromatogram with only one r eference spot is possible. H ere again scanning and da t a acquisition can be fully automated. The application of proper calibration procedures ~o differential reflectance techniques and the measurement of mult i-component systems I...

show abstract

Section: Calibrationmentioning

confidence: 73%

“… Schematic representation of the scanning pattern employed for the two-dimensional integration principle [ 35 ]. …”

Section: Figurementioning

confidence: 99%

Diffuse reflectance spectroscopy; applications, standards, and calibration (with special reference to chromatography)

Frei¹

1976

J. RES. NATL. BUR. STAN. SECT. A.

View full text Add to dashboard Cite

show abstract

“…Most workers use empirical calibration curves and two major points of controversy remain unresolved. These concern (a) the relative merits of reflectance vs. transmission densitometry (4, 8, 9) and (b) the apparent conflict of the last 3 decades between those studies reporting linear and those reporting nonlinear absorbance/concentration curves with transmission densitometry (4, 6, 8, 9, 13, 14, [23][24][25][26][27][28][29]. With fluorometry, Goldman predicted bilinear emission/concentration curves: but most results suggest linear functions (e.g., ref 4 and 29) and Hurtubise (10) obtained only partial experimental agreement with Goldman's theory.…”

Section: Discussionmentioning

confidence: 99%

Computer simulation of light transmission through scattering and absorbing chromatographic media

Bush¹,

Greeley²

1984

Anal. Chem.

View full text Add to dashboard Cite

Synthesis and characterization of poly(LysAla₃)

et al. 1974

View full text Add to dashboard Cite

SynopsisThe synthesis and characterization of poly(LysAlaa) are described. The polytetrapeptide is a model for short sequences found in proelastin, and is presumably involved in desmosine or isodesmosine cross-link formation in the native protein. Poly(LysAla3) is found to possess a mixture of conformations in aqueous solution dependent on molecular weight and pH. Low-molecular-weight (ca. 3000) material appears to be a mixture of random and extended helix at neutral pH. However, as the molecular weight is increased an increasing amount of a-helix is observed rising to >50% for mol wt = 21,000. The a-helical chain segments are thermally stable, melting to a mixture of extended and random forms at T, = 25°C. High pH (10.5) promotes further a-helix formation but at pH >11.0 the polypeptide becomes insoluble. The inference is that short chain segments of the peptide in elastin are unlikely to be a-helical in the equilibrium state but may fluctuate through such a conformation.

show abstract

Zurstandardisierung der direkten spektrophotometrischen auswertung von chromatogrammen

Cited by 13 publications

References 18 publications

Diffuse reflectance spectroscopy; applications, standards, and calibration (with special reference to chromatography)

Diffuse reflectance spectroscopy; applications, standards, and calibration (with special reference to chromatography)

Computer simulation of light transmission through scattering and absorbing chromatographic media

Synthesis and characterization of poly(LysAla₃)

Contact Info

Product

Resources

About

Zurstandardisierung der direkten spektrophotometrischen auswertung von chromatogrammen

Cited by 13 publications

References 18 publications

Diffuse reflectance spectroscopy; applications, standards, and calibration (with special reference to chromatography)

Diffuse reflectance spectroscopy; applications, standards, and calibration (with special reference to chromatography)

Computer simulation of light transmission through scattering and absorbing chromatographic media

Synthesis and characterization of poly(LysAla3)

Contact Info

Product

Resources

About

Synthesis and characterization of poly(LysAla₃)