Structural Characterization of a Fulvic Acid and a Humic Acid Using Solid-State Ramp-CP-MAS13C Nuclear Magnetic Resonance

1998 ◽  
Vol 32 (5) ◽  
pp. 719-725 ◽  
Author(s):  
Robert L. Cook ◽  
Cooper H. Langford
Biochemistry ◽  
2008 ◽  
Vol 47 (15) ◽  
pp. 4369-4376 ◽  
Author(s):  
Karsten Seidel ◽  
Ovidiu C. Andronesi ◽  
Joachim Krebs ◽  
Christian Griesinger ◽  
Howard S. Young ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chuanjiang Li ◽  
Hui Wang ◽  
Manuel Juárez ◽  
Eric Dongliang Ruan

Maillard reaction is a nonenzymatic reaction between reducing sugars and free amino acid moieties, which is known as one of the most important modifications in food science. It is essential to characterize the structure of Amadori rearrangement products (ARPs) formed in the early stage of Maillard reaction. In the present study, the Nα-acetyl-lysine-glucose model had been successfully set up to produce ARP, Nα-acetyl-lysine-glucose. After HPLC purification, ARP had been identified by ESI-MS with intense [M+H]+ ion at 351 m/z and the purity of ARP was confirmed to be over 90% by the relative intensity of [M+H]+ ion. Further structural characterization of the ARP was accomplished by using nuclear magnetic resonance (NMR) spectroscopy, including 1D 1H NMR and 13C NMR, the distortionless enhancement by polarization transfer (DEPT-135) and 2D 1H-1H and 13C-1H correlation spectroscopy (COSY) and 2D nuclear overhauser enhancement spectroscopy (NOESY). The complexity of 1D 1H NMR and 13C NMR was observed due to the presence of isomers in glucose moiety of ARP. However, DEPT-135 and 2D NMR techniques provided more structural information to assign the 1H and 13C resonances of ARP. 2D NOESY had successfully confirmed the glycosylated site between 10-N in Nα-acetyl-lysine and 7′-C in glucose.


Author(s):  
Heitor Secco Seleghini ◽  
Heloise de Oliveira Pastore ◽  
Fábio Aurélio Bonk

This work reports the characterization using solid-state NMR of the second generation of the UEC family of molecular sieves, such generation is composed by two tridimensional silicoaluminophosphates synthesized from a layered aluminophosphate (AlPO-CJ70). The 3D structures are analogous to SAPO-5 (UEC-4) and SAPO-15 (UEC-5), both were characterized using multinuclear solid-state NMR, 27Al-MQ-MAS and 29Si{27Al} TRAPDOR.


Sign in / Sign up

Export Citation Format

Share Document