Research On The Determination Of Sulfonamides In Food

Sulfonamides (SAs) are a large group of broad-spectrum synthetic antibiotics widely used in veterinary therapy for the treatment and prevention of several bacterial infections, which is a class of drugs have the sulfanilamide structure. Since1932, the type of SAs have reached thousands of species, which due to the broad-spectrum antibiotic, largely used for the prevention and treatment drugs and used as animal growth additives. 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 environment. Because the metabolic effects of SAs in animals cost a long time. Therefore, it is necessary to develop a series of simple, reliable and convenient methods for the determination of sulfonamides. This paper studies the fluorescence detection method about SAs, the main contents are as follows:Chapter1Vortex assisted liquid-liquid microextraction (VALLME) coupled to fluorescence spectrometric for the analysis of sulfonamides residues in meatThree sulfonamides (sulfadiazine sodium, sulfamethoxazole and sulfaguanidine) in the presence of o-phthalaldehyde produced an isoindole derivative which can produce strong fluorescence. And a new method was built for the detection of SAs by fluorescence spectrometric. Nonanoic acid was used for the extraction of the derivative to bring down the detection limit largely. Under the optimum conditions, linear ranges for sulfonamides determination were5-5000ng/mL with the detection limit was0.5-2.0ng/mL. And the recoveries were94.1%-100.2%with spiked recovery experiments. The results show that the method is suitable for the detection of three sulfonamides, which residues in pork.Chapter2Ultrasound-assisted Nonylphenol Ethoxylate cloud point extraction combined with fluorescence for the determination of sulfonamides in honeyA sensitive spectrofluorimetric method was developed for the determination of sulfadiazine sodium and sulfamerazine, which sulfadiazine sodium and sulfamerazine in the presence of fluorescamine produces a fluorescent derivative. Nonylphenol Ethoxylate was used for the cloud point extraction of the derivative to bring down the detection limit largely. The cloud point of Nonylphenol Ethoxylate is about35℃, which is suitable for heat-sensitive substances. The recovery of this method was80.2%-93.0%. And the relative standard deviation was2.2%-4.1%. Besides, the limit of detection was0.5-5.0ng/mL. This method is sensitive, simple and accurate, which has been successfully applied in the honey, which bought formYunnan local supermarket.Chapter3N-octanol assisted fatty alcohol polyoxyethylene ether cloud point extraction combined with fluorescence spectrometric for the determination of sulfonamides in milkAn n-octanol assisted fatty alcohol polyoxyethylene ether cloud point extraction combined with spectrofluorimetric method was developed for the determination of sulfadiazine sodium, sulfamethoxazole and sulfaguanidine in milk. Based on the cloud point extraction, n-octanol was added to decrease the cloud point of AEO-9, as well as the mechanism of lowering the cloud point was explored. And three sulfonamides in the presence of o-phthalaldehyde produced a derivative which can produce strong fluorescence. A simple and high sensitivity method was developed for the determination of sulfonamides by optimizing the cloud point extraction technology, and the calibration graph was linear from5-4000ng/mL with the recoveries higher than90%. And the results show that the method can be used to detect sulfonamides in milk.