Chlorophenols dansylation

This type of derivatization seems promising for the detection of drugs and metabolites with phenolic groups. A recent application on the determination of chlorophenols in surface water showed that the dansyl derivatives of phenols are readily convertible to the highly fluorescent dansyl-OH and dansyl-OCHs products after postchromatographic irradiation (281). Fluorescence gain factors of up to 8000-fold were obtained for chlorophenol derivatives with a low native fluorescence. 

Reagents. Certified A.C.S. spectroanalyzed methanol, phenol, m-nitrophenol, benzene, naphthalene, sodium acetate, and acetic acid were obtained from Fisher Scientific and were used as received. The e-CD, dansyl-DL-leucine, dansyl-DL-norleucine (all from Signal Chemical Co., St. Louis, MO), o-chlorophenol, m-chlorophenol, p-chlorophenol, o-nitrophenol (all from Eastman Kodak Co., Rochester, NY), p-nitrophenol, and biphenyl (from MCB, South Plainfield, NJ) were all used as received. 

Most studies in TLC have been qualitative, and considerable experimentation may be necessary to obtain quantitative results, although excellent commercial layers and new equipment have aided the problem. Phenolic compounds have been analyzed by spectrophotometry off the plate at 725 nm (133) by means of Folin-Ciocalteu reagent, essentially sodium tungstate and molybdate with lithium sulfate (134). Chlorophenols have been quantified after reaction with dansyl chloride and separation (135). Channel TLC (linear relationships between spot lengths and concentration between 1 and 8 pg/spot) has been used (136). The phenols in cashew nut shell liquid have been quantified by off and on the plate methods with a flying-spot scanning procedure and densitometry (137) and the distribution of unsaturateds by TLC/MS (138). Catecholamines and their metabolites in urine have been quantified (12) and determined by on the plate fluorimetry (139). Hindered phenols have been analyzed by densitometry (140). Semiquantitative determinations of the coupling products of 4,4 -... 

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