Quantitation of crystalline and amorphous forms of anhydrous neotame using 13C CPMAS NMR spectroscopy

Offerdahl, Thomas J.; Salsbury, Jonathon S.; Dong, Zedong; Grant, David J.W.; Schroeder, Stephen A.; Prakash, Indra; Gorman, Eric M.; Barich, Dewey H.; Munson, Eric J.

doi:10.1002/jps.20469

Cited by 78 publications

(51 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A clear distinction must be made between data that are truly quantitative, data that are semiquantitative, and qualitative trends where numerical comparisons cannot be made. This is especially important for techniques such as NMR, where common methods, such as cross-polarization, will provide quantitative spectra only under very specific analysis conditions (103,104). For other techniques, such as X-ray photoelectron spectroscopy, that are frequently used to probe substrate-heteroatom interactions but have not been implemented for the analysis of Lewis acid zeolites, it is critical to conduct proper control experiments.…”

Section: Discussionmentioning

confidence: 99%

Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

Luo

Lewis

Román‐Leshkov

2016

Annu. Rev. Chem. Biomol. Eng.

151

136

View full text Add to dashboard Cite

Zeolites containing Sn, Zr, Hf, Nb, or Ta heteroatoms are versatile catalysts for the activation and conversion of oxygenated molecules owing to the unique Lewis acid character of their tetrahedral metal sites. Through fluoride-mediated synthesis, hydrophobic Lewis acid zeolites can behave as water-tolerant catalysts, which has resulted in a recent surge of experimental and computational studies in the field of biomass conversion. However, many open questions still surround these materials, especially relating to the nature of their active sites. This lack of fundamental understanding is exemplified by the many dissonant results that have been described in recent literature reports. In this review, we use a molecular-based approach to provide insight into the relationship between the structure of the metal center and its reactivity toward different substrates, with the ultimate goal of providing a robust framework to understand the properties that have the strongest influence on catalytic performance for the conversion of oxygenates.

show abstract

Section: Discussionmentioning

confidence: 99%

Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

Luo

Lewis

Román‐Leshkov

2016

Annu. Rev. Chem. Biomol. Eng.

151

136

View full text Add to dashboard Cite

show abstract

“…At 15% L-proline, DL-II dominates the spectrum, but peaks for DL-MH, DL-I, and L-CD are still visible. Because NMR is an inherently quantitative technique, 28 it was possible to calculate the amount of L-CD present in each solid sample. Figure 6 is a plot of the amount of chiral defects in each sample as determined from 13 C CP-MAS NMR spectra in Figure 5.…”

Section: Choice Of Crystallization Methodsmentioning

confidence: 99%

Detection of Chiral Defects in Crystalline Organic Solids Using Solid-State NMR Spectroscopy

Berendt

Munson

2011

Journal of Pharmaceutical Sciences

Self Cite

View full text Add to dashboard Cite

“…[1][2][3][4][5][6][7][8][9][10][11] For example, the polymorphs for each drug substance, i.e., the active pharmaceutical ingredient, need to be identified and quantified before the commercial use of drug substances. The characterization and quantification of each phase in a sample have enabled even a precise diagnosis of diseases such as urolithiasis and a prophylaxis, 1 an estimation of the lixiviation performance of the host for radioactive elements, 2 and the deciphering of the magma mixing phenomena.…”

Section: Introductionmentioning

confidence: 99%

“…3 Consequently, many studies have quantified solid-state structures and phases by various spectroscopic methods. [1][2][3][4][5][6][7][8][9][10][11][12] However, powder sample mixing to obtain calibration curves and to apply a standard addition method 9 causes significant variance in the quantification of solid-state phases, in contrast to liquid samples, due to the difficulty in ensuring a homogeneous mixing of solid-state polycrystalline powders. Especially with limited sample amounts, a larger error may be produced due to the presence of remnants on the surface of mixing tools.…”

Section: Introductionmentioning

confidence: 99%

Sampling Methods for Quantification of Solid-state Phases in Powder Samples with Solid-state NMR Spectroscopy

Han

Kim²,

Ko³

2009

Bulletin of the Korean Chemical Society

View full text Add to dashboard Cite

To minimize the variance in the quantification of solid-state phases in powder samples, gently placing polycrystalline samples one next to another directly in a sample holder is better than trying to mix them homogeneously prior to transferring to a sample holder. However, the solid-state cross polarization-magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy results demonstrated that it is essential in this sampling method to place all the samples in the location of consistent signal sensitivity. The same sampling method may be employed in other spectroscopic quantification techniques of solid-state phases if the method to limit the sample to the location with uniform signal sensitivity in the sample holder is adapted to each technique.

show abstract

Quantitation of crystalline and amorphous forms of anhydrous neotame using 13C CPMAS NMR spectroscopy

Cited by 78 publications

References 40 publications

Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

Detection of Chiral Defects in Crystalline Organic Solids Using Solid-State NMR Spectroscopy

Sampling Methods for Quantification of Solid-state Phases in Powder Samples with Solid-state NMR Spectroscopy

Contact Info

Product

Resources

About