Sulfonamide detection chromatographic

The amino group is readily dia2oti2ed in aqueous solution, and this reaction forms a basis for the assay of sulfas. Aldehydes also react to form anils, and the yellow product formed with 4-(dimethylamino)hen2a1dehyde can be used for detection in thiu-layer and paper chromatography. Chromatographic retention values have been deterrnined in a number of thiu layer systems, and have been used as an expression of the lipophilic character of sulfonamides (23). These values have corresponded well with Hansch lipophilic parameters determined in an isobutyl alcohol—water system. 

Following their extraction and cleanup, residues of sulfonamides and diaminopyrimidine potentiators in sample extracts can be detected by direct nonchro-matographic methods, or thin-layer, gas, liquid, or supercritical fluid chromatographic methods (Table 29.7). 

In thin-layer chromatographic methods, sulfonamide residues were first separated on commercially available silica gel plates using various solvent mixtures as mobile phase, and subsequently detected by fluorometry after spraying... 

Tsai, C.-E. Kondo, F. A sensitive high-performance liquid chromatographic method for detecting sulfonamide residues in swine serum and tissues after fluorescamine derivatization. J.Liq.Chromatogr,... 

Agababa et al. (1996) developed a simple method for TLC determination of sulfamethoxazole, trimethoprim, and impurities of sulfanilamide and sulfanilic acid using a chloroform-n-heptane-ethanol (3 3 3) mobile phase. The zones were quantified by scanning densitometry in the reflectance/absorbance mode at 260 nm. Abjean (1997) described a method for multiclass and multiresidue qualitative detection of chloramphenicol, nitrofuran, and sulfonamide residues in animal muscle. The drugs were extracted from 1 gram of tissue with 2 ml of ethanol acetate and purified by silica solid-phase extraction. After elution of the cartridge, the collection solution was evaporated the residue was dissolved in methanol and chromatographed on silica gel 60-HPTLC plates. 

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