title: Comparison of UV and fluorescence spectrophotometry for the quantification of a potent myotonia inducer: anthracene-9-carboxylic acid, in plasma, urine, and saline perfusion fluids.
abstract: UV and fluorescence spectrophotometry were used to establish the analytical profile of a potent myotonia inducer, anthracene-9-carboxylic acid (I). UV spectrophotometry is useful for the determination of I when it is dissolved in physiological solutions (Ringer's, Tyrode's, etc). In these fluids there is a linear relationship between UV absorption and I concentration between 500 and 2000 ng/ml (2.25-9.0 X 10(-6)M). However, in biological fluids there are interferences in the UV absorption due to organic substances. On the other hand, fluorescence spectrophotometry is more sensitive than UV for determinations in plasma and urine. Within the range of 200-1000 ng/ml (0.9-4.5 X 10(-6) M) fluorescence intensity increases linearly with concentration. Furthermore, when both emission and excitation spectra are combined there are no interferences due to organic substances normally present in those fluids. An extraction procedure of I from plasma and urine is also described, and the importance of I determinations in relation to the problem of this myotonia-inducing aromatic monocarboxylic acid is discussed.
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000032:analysis* / Q000097:blood / Q000652:urine; D011817:Rabbits; D012965:Sodium Chloride / Q000032:analysis; D012996:Solutions / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: D000873:Anthracenes; D012996:Solutions; D012965:Sodium Chloride; C010030:9-anthroic acid