Triamcinolone acetonide acetate

In the crystal structure of the title compound [systematic name: 2-(4b-fluoro-5-hy­droxy-4a,6a,8,8-tetra­methyl-2-oxo-2,4a,4b,5,6,6a,9a,10,10a,10b,11,12-dodeca­hydro-7,9-dioxa­penta­leno[2,1-a]phenanthren-6b-yl)-2-oxoethyl acetate], C26H33FO7, the mol­ecules are connected by inter­molecular O—H⋯O hydrogen bonds into an infinite supra­molecular chain along the b axis. The mol­ecular framework consists of five condensed rings, including three six-membered rings and two five-membered rings. The cyclo­hexa-2,5-dienone ring is nearly planar [maximum deviation = 0.013 (3) Å], while the cyclo­hexane rings adopt chair conformations. The two five-membered rings, viz. cyclo­pentane and 1,3-dioxolane, display envelope conformations

Bupropion hydro­bromide propanol hemisolvate

The title compound {systematic name: N-[1-(3-chloro­phen­yl)-1-oxopropan-2-yl]-tert-butanaminium bromide propanol hemisolvate}, C13H19ClNO+·Br−·0.5C3H8O, crystallizes with two independent bupropion hydro­bromide ion pairs and a solvent 1-propanol mol­ecule in the asymmetric unit. In both mol­ecules, the expected proton transfer from HBr to the amino group of the bupropion mol­ecule is observed, and intra- and inter­molecular N—H⋯Br hydrogen-bond inter­actions are formed. These inter­actions link the mol­ecules into hydrogen-bond dimers. The side chains of the two cations have slightly different orientations. The 1-propanol solvent mol­ecule is linked to a bromide ion by an O—H⋯Br hydrogen bond

Febuxostat methanol solvate

In the title compound {systematic name: [2-(3-cyano-4-isobutyl­oxyphen­yl)-4-methyl-1,3-thia­zole-5-carb­oxy­lic acid (febuxostat) methanol monosolvate}, C16H16N2O3S·CH4O, the benzene and thia­zole rings in the febuxostat mol­ecule are twisted at 5.3 (1)°. In the crystal structure, inter­molecular O—H⋯O and O—H⋯N hydrogen bonds link the febuxostat and methanol mol­ecules into helical chains along the 21 screw axis

Possible Influences on Ammonia Nitrogen Determination by Nessler's Reagent Spectrophotometry

Nessler's reagent spectrophotometry is the traditional method for ammonia nitrogen (NH3-N) determination, which is adopted in the national standard of the People's Republic of China (HJ 535-2009). In order to improve the accuracy of such method, possible influences, Nessler's Reagent preparation, pH value of the solution, metal ions, organic solvents and natural organic matters, on NH3-N determination were discussed. The results suggested that the method B, employing KI, HgI2 and NaOH, is preferred in Nessler's Reagent preparation. And the Nessler's Reagent Spectrophotometry may be executed over a wide pH range (4-11). The metal ions, organic solvents and natural organic matters have significant influences in NH3-N detection. Keywords Nessler's Reagent, Ammonia Nitrogen, pH, Metal Ion, Organic Solvent, Natural Organic Matter. DOI: 10.7176/JNSR/11-24-02 Publication date: December 31st 202