scholarly journals Vibrational spectroscopy of the cryogenically cooled O- and N-protomers of 4-aminobenzoic acid: Tag effects, isotopic labels, and identification of the E,Z isomer of the O-protomer

2020 ◽  
Vol 457 ◽  
pp. 116427
Author(s):  
Thien Khuu ◽  
Nan Yang ◽  
Mark A. Johnson
1974 ◽  
Vol 35 (C6) ◽  
pp. C6-131-C6-137 ◽  
Author(s):  
Y. HAZONY ◽  
R. H. HERBER

2013 ◽  
Vol 12 (10) ◽  
pp. 719-726
Author(s):  
R. Ayadi ◽  
Mohamed Boujelbene ◽  
T. Mhiri

The present paper is interested in the study of compounds from the apatite family with the general formula Ca10 (PO4)6A2. It particularly brings to light the exploitation of the distinctive stereochemistries of two Ca positions in apatite. In fact, Gd-Bearing oxyapatiteCa8 Gd2 (PO4)6O2 has been synthesized by solid state reaction and characterized by X-ray powder diffraction. The site occupancies of substituents is0.3333 in Gd and 0.3333 for Ca in the Ca(1) position and 0. 5 for Gd in the Ca (2) position.  Besides, the observed frequencies in the Raman and infrared spectra were explained and discussed on the basis of unit-cell group analyses.


Author(s):  
Hind Hadi ◽  
Gufran Salim

A simple, rapid and sensitive spectrophotmetric method for trace determination of salbutamol (SAL) in aqueous solution and in pharmaceutical preparations is described. The method is based on the diazotization coupling reaction of the intended compound with 4-amino benzoic acid (ABA) in alkaline medium to form an intense orange, water soluble dye that is stable and shows maximum absorption at 410 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 0.5-30 ppm, with a molar absorbtivity 3.76×104 L.mol-1 .cm-1 depending on the concentration of SAL. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of SAL in dosage forms.


Author(s):  
Magdi Mossoba ◽  
◽  
Sanjeewa Karunathilaka ◽  
Kyungeun Lee ◽  
Lea Brückner ◽  
...  

2020 ◽  
Vol 14 (5) ◽  
pp. 835-841
Author(s):  
S. I. Lazarev ◽  
Yu. M. Golovin ◽  
I. V. Khorokhorina ◽  
D. S. Lazarev

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