Oxidation of erythromycin, sulfamethazine and sulfathiazole by ozone was experimentally investigated to see the effects of background water quality such as ultrapure water, humic acid and biologically treated wastewater and water temperature on the removal rate, consequently to provide design information when the ozone treatment process is adopted. Initial concentration of the antibiotics was spiked to 10 μg/l and ozone dose was 1, 2, 3, 5, 8 mg/l. While the removal rate of erythromycin under ultrapure water background by ozone oxidation was over 99%, that under humic acid and biologically treated wastewater background was markedly reduced to the range of 59.8%~99% and 17.0%~99%, respectively. When water temperature is decreased from 20℃ to 4℃, the removal rate is reduced from the range of 17.0%~99% to the range of 9.4%~97.4% under biologically treated wastewater background. The effects of background and temperature on the removal rate of sulfamethazine and sulfathiazole were similar to erythromycin, but the degree was different. Therefore, it is concluded that the background of water to be treated as well as water temperature should be taken into consideration when the design factor such as ozone dose is determined to meet the treatment objective in the ozone treatment process.

A rapid, simple and reliable LC-MS/MS method, which can be used on a routine basis, was developed for the simultaneous detection of 8 penicillin antibiotics (amoxicillin, ampicillin, penicillin-G, penicillin-V, oxacillin, cloxacillin, nafcillin and dicloxacillin) in swine muscle and kidney. The antibiotics were extracted from samples with water and methanol. The extract was centrifuged, filtered and analyzed by liquid chromatography coupled with a tandem mass spectrometer (LC-MS/MS), using a C18 reversed phase column with water/acetonitrile gradient containing 0.05 % formic acid. Mass spectral acquisition was achieved in an electrospray positive ion mode by applying multiple reaction monitoring (MRM) of 2 fragment ion transitions to provide a high degree of sensitivity and specificity. The ion rations were consistent and could be used for confirmation of identity of the penicillin antibiotics. Recoveries of eight penicillins at three fortification levels (10, 20 and 40㎍/㎏) ranged from 79.8 to 102.4% and 72.8 to 103.4% in swine muscle and kidney, respectively. The coefficient of variation was than 9% in all samples. The estimated limits of quantification (LOQs) ranged from 1.0 to 3.2㎍/㎏ in swine muscle and kidney, respectively. The LOQs of this method are below the MRLs of penicillin antibiotics in animal tissues established in Korea and other countries.

A simple, rapid and simultaneous analytical method is described for the detection of Sulfonamide and Tetracycline residues, i.e., Sulfamerazine (SMR), Sulfamethazine (SMT), Sulfamonomethoxine (SMM), Sulfadimethoxine (SDM), Sulfaquinoxaline (SQN), Oxytetracycline (OXY), Tetracycline (TC), Chlortetracycline (CTC). Blank control and sulfonamide and tetracycline fortified fish muscle samples (0.5 g) were blended with octadecylsilyl (C,e, 40 gm, 21% load, 60Å) derivatized silica packing material (2 g). Blended fish samples were washed with hexane, then, benzene and dichloromethane were used for the elution of tetracycline and sulfonamide, respectively, The eluants containg tetracycline and sulfonamide were analyzed by HPLC. Correlation coefficients of standard curves for individual sulfonamide and tetracycline isolated from fortified samples were linear (0.9993±0.0003-0.9997±0.0003, 0.9493±0.078-0.9753±0.036), respectively, The average percentage recoveries of sulfonamide and tetracycline ranged as 80.86-96.52% to 85.88-92.23%, and 30.01-37.12% to 65.89-73.40%, for the concentration range (0.1--1.0 ppm) examined, respectively. Limit of detection for sulfonamide was 0. 05 ug/g, then, tetracycline was 0.1 ug/g. Detection of quantitation of sulfonamide residue was 0.0012 ppm for SMR in Paralichthys Odiuacleus and 0.0020 ppm for SMR, 0.015 ppm for SMM in Cyprinus Carpio. The applicability of this procedure is demonstrated by separation and detection of incurred tetracycline and sulfonamide residues in fish muscle tissue.

Recently, as concern about the residual antibiotics in milk increase, the detection methods of residual antibiotics used extensevely at the present time were investigated and compared to their properties and the detection limits of variable antibiotics. At first, comparative tests of the detectable sensitivity of 4 teat organisms, B.cereus, B.subtilis, M.luteus, B. stearothermophilus C-953, were performed by disc assay. As a result, B.stearotleermoph.ilus was the most sensitive strain of all other strains and showed the detect limit of 5-50 ppb for penicillins (PCs). And also, B.subtilis was showed the more effective detection limit, 200-400 ppb, for aminoglycosides (AGs) and M.luteus was showed predominant sensitivity , 50-500 ppb for macrolides(MLs) and B.cereus was the most sensitive strain for tetracyclines (TCs) and showed the detection limit of 100-400 ppb. Therefore, each test strains were showed a different sensitivity in the detection of the different antibiotic families. When the detection limit of disc assay and other methods were compared, TTCmethod was less sensitive than other methods showing 5-50 ppb detectable lebel for PCs. Also, for the detection of other antibiotic families TTC method was showed the worst sensitivity and Delvo and Charm Farm tests were similar to the detectable properties of AGs and MLs. Although disc assay was showed the similar detection limit for PCs with Delvo and Charm Farm, it was more widely effective for the detection of kanamycin, erythromycin, chlortetracycline, doxycycline, verginiamycin and so on than Delvo or Charm Farm. CharmII test was showed the best sensitivity for the most of antibiotics except neomycin and gentamycin. But it was necessary that different tests must be performed to each antibiotic family and so it was regarded that the effectiveness of that method was low.