Spectrophotometry in Medicine

Fluorescence Spectrophotometry

Fluorescence and phosphorescence are photon emission processes that occur during molecular relaxation from electronic excited states. These photonic processes involve transitions between electronic and vibrational states of polyatomic fluorescent molecules (fluorophores). The Jablonski diagram (Figure 1) offers a convenient representation of the excited state structure and the relevant transiti...

Low-temperature spectrophotometry

Photoreactions of the fourth rhodopsin-like pigment, phoborhodopsin (pR480), of Hulobacrerium halobium were studied by low-temperature spectrophotometry. Upon irradiation of pR480 at -80 as well as 170°C with 436 nm light, a new intermediate having a difference absorption maximum at about 520 nm was produced. We designate this intermediate ‘P520’. Prolonged irradiation caused the formation of a...

Basic UV/Visible Spectrophotometry

Semiautomated spectrophotometry of total phospholipids in plasma.

A one-stage semiautomated method for estimating total phospholipids in plasma is reported. The phospholipids are extracted into aqueous ethanol, combined with a Lewis acid, and the change in pH is monitored colorimetrically. The method, compared with the acid digestion method of Gomori [J. Lab. Clin. Med. 27, 955 (1942)], gives results that are about 0.25 mmol/liter lower, but seems to be a sui...

Spectrophotometry of proline in plasma and urine.

A procedure is presented for proline quantification in serum filtrates and urine hydrolysates. Interference from primary amino acids is greatly reduced by nitrozation. After nitrozation and neutralization, protine is reacted with ninhydrin in a concentrated electrolyte solution. The resulting red proline-ninhydrin product is salted out, extracted into benzene, and measured at 520 nm. The extent...