Portal de Periódicos da CAPES

Caffeine

1986; Elsevier BV; Linguagem: Inglês

10.1016/s0099-5428(08)60413-x

2163-5846

Mohammad Uppal Zubair, M. M. A. Hassan, I.A. Al-Meshal,

Diet and metabolism studies

Caffeine is white powder, having an appearance of glistening needles, usually matted together. It is odorless and has a bitter taste. It melts between 235˚C and 237.5˚C, determined after drying at 80º for 4 hours. Caffeine sublimes at 178˚C. Fast sublimation is obtained at 160–165˚C under 1 mm pressure at 5 mm distance. Sutor has determined the crystal structure of caffeine. The infrared (IR) spectrum of caffeine as KBr disc was recorded on a Perkin Elmer-580 B infrared spectrophotometer to which an infrared data station was attached. The mass spectrum of caffeine obtained by electron impact ionization (EI) was recorded on Finigan-Mat 1020 GC/mass spectrometer. Caffeine has also been synthesized from uric acid. The absorption of caffeine from the gastrointestinal tract is rapid but irregular. It is distributed in various tissues of the body in approximate proportion to their water content.