Study On The Determination Of Sulfonamides In Food Of Animal Origin

Sulfonamides (SAs) are a large group of broad-spectrum synthetic antibiotics widely used in veterinary therapy for the treatment and prevention of several bacterial and protozoan infections in food producing animals. However, the irregular and abusive use of sulfonamides will lead to drug residues in animal-derived food and finally do harm to human health and the environment. Therefore, it is significant to develop a series of sensitive, reliable and convenient methods for the determination of sulfonamides. In this paper, fluorescence and HPLC analysis of sulfonamides, such as sulfadiazine (SD), sulfaguanidine (SG), sulfamethoxazole (SMX), sulfamerazine (SM1), sulfadimidine (SM2) have been studied. The main contents are as follows:Part Ⅰβ-cyclodextrin enhanced fluorimetric method for the determination of sulfamerazine in meat samplesA simple sensitive spectrofluorimetric method was developed for the determination of sulfamerazine. sulfamerazine in the presence of fluorescamine produces a fluorescent derivative, whose fluorescence intensity can be enhanced by forming an inclusion complex with β-cyclodextrin (β-CD). Optimum conditions for the determination of sulfamerazine were also investigated. Fluorimetric detection was earried out at λex of410nm and λem of495nm. The linear range of this method for the determination of sulfamerazine is1-300μg/L and the limit of detection is0.3μg/L with a correlation coefficient (r) of0.9997. The developed method is practical and can be successfully applied to determine the content of sulfamerazine in meat samples with satisfactory results.Part Ⅱ Study on the fluorescence spectrometric determination of four sulfonamides by derivatization reaction with o-phthalaldehydeA precise and reliable fluorimetric method for the determination of four sulfonamide antibiotics (sulfadiazine, sulfaguanidine, sulfamethoxazole, sulfamethazine) in milk samples has been developed. Sulfonamide in the presence of o-phthalaldehyde produces an isoindole derivative which can produce strong fluorescence. N-butanol was used for the extraction of the derivative to bring down the detection limit largely. Optimum conditions for the determination of sulfonamides were also investigated. Fluorimetric detection was carried out at λex of295nm and λem of425nm. Linear ranges for sulfonamides determination were5-500μg/L. The developed method is practical and can be successfully applied to determine the content of sulfonamides residues in milk samples with satisfactory results.Part Ⅲ A mixed micelle aqueous two-phase system for the determination of sulfonamidesA mixed micelle aqueous two-phase system (MM-ATPS) coupled with high performance liquid chromatography (HPLC) method was developed for the extraction and determination of sulfonamides (sulfadiazine (SD), sulfaguanidine (SG), sulfamethoxazole (SMX), sulfamerazine (SM1), sulfadimidine (SM2)) in honey samples using polyethylene glycol (PEG6000) and sodium dodecyl sulfate (SDS) as the extraction mediums. The method is based on the mixed micelle-mediated extraction of sulfonamides in the presence of Na2CO3as an inducing agent in phase separation. Parameters that affect the efficiency of the MM-ATPS were investigated. Under the optimum conditions, the linear concentration range of SD, SG, SMX and SM2were at5-1000μg/L,10-1000μg/L for SM1. The correlation coefficient of the calibration curves ranged from0.9971to0.9988. The relative standard deviations (RSD) were2.36-4.38%(n=5) and the detection limits (LOD) based on a signal-to-noise ratio (S/N) of3were0.1,0.1,0.1,0.1and0.5μg/L for SD, SG, SMX, SM1, and SM2respectively. The proposed procedure was applied successfully for the detection of the investigated drugs in honey samples with good precision and accuracy..