Bridging of a Liquid Chromatography-Tandem Mass Spectrometry Method for Oxytetracycline, Chlortetracycline, and Tetracycline in Bovine Kidney with the Official Microbial Growth Inhibition Assay.

Background: Oxytetracycline (OTC), chlortetracycline (CTC), and tetracycline (TC) are approved antibiotics used to treat bacterial infections in cattle. To ensure human food safety, a tolerance has been established for the sum of these three TC residues as 12 parts per million in bovine kidney in the United States The current official regulatory method for quantifying these antibiotics in the target organ is a labor-intensive microbiological assay.

Objective: Our laboratory developed and validated a fast, selective, and less laborious method utilizing LC-tandem mass spectrometry for the determination and confirmation of the three tetracyclines (TET) in bovine kidney.

An LC-MS/MS Method for the Determination of Antibiotic Residues in Distillers Grains: Collaborative Study.

Background: Antibiotics are used in ethanol production to discourage the growth of bacteria that would lower the yield of the product. Any antibiotic residues remaining in distillers grain (DG) co-product could lead to antimicrobial resistance, which is a public health concern. The U.

Screening for toxic phorbol esters in jerky pet treat products using LC-MS.

Since 2007, the U.S. FDA's Center for Veterinary Medicine (CVM) has been investigating reports of pets becoming ill after consuming jerky pet treats.

Determination of erythromycin in medicated salmonid fish feed by liquid chromatography and UV spectroscopy.

A simple, robust LC-UV method was developed to assay erythromycin in medicated salmonid feed. In this method, erythromycin was extracted from feed with acetonitrile and water, cleaned up by SPE, evaporated to dryness, reconstituted, and analyzed by LC-UV. The resulting method produced high accuracy, 82-90%, for both salmon and trout feed that represented varied pellet sizes and ingredient amounts.

Development of a quantitative multiclass/multiresidue method for 21 veterinary drugs in shrimp.

A multiclass/multiresidue method has been developed and validated for the determination of 21 veterinary drug residues in shrimp, including sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfachloropyridazine, sulfadimethoxine, and sulfaquinoxaline); tetracyclines (oxytetracycline, tetracycline, and chlortetracycline); (fluoro)quinolones (norfloxacin, ciprofloxacin, enrofloxacin, sarafloxacin, difloxacin, flumequine, oxolinic acid, and nalidixic acid); and cationic dyes (malachite green, gentian violet, leucomalachite green, and leucogentian violet), using HPLC/MS/MS. All drugs were quantifiable over a no less than 10-fold range with matrix-matched standards for linear external calibration, except for oxytetracycline, tetracycline, norfloxacin, and ciprofloxacin, for which norfloxacin-d5 was used as an internal standard. Two grams of preground shrimp sample was extracted twice with extractant at two different pH values.

Determination of sulfadimethoxine and 4N-acetylsulfadimethoxine in bovine plasma, urine, oral fluid, and kidney and liver biopsy samples obtained surgically from standing animals by LC/MS/MS.

A quantitative method was developed and validated to measure the concentration of sulfadimethoxine (SDM) and its major metabolite, (4)N-acetylsulfadimethoxine (AcSDM), in bovine tissues and body fluids. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) gave quantitative results for these two analytes in extracts from bovine plasma, urine, oral fluid, kidney, and liver, using SDM-d(4) as internal standard (I.S.

Analysis of veterinary drug residues in shrimp: a multi-class method by liquid chromatography-quadrupole ion trap mass spectrometry.

A liquid chromatography-mass spectrometry (LC-MS) method was developed to screen and confirm veterinary drug residues in raw shrimp meat. This method simultaneously monitors 18 drugs of different classes, including oxytetracycline (OTC), sulfonamides, quinolones, cationic dyes, and toltrazuril sulfone (TOLS). The homogenized shrimp meat is extracted with 5% trichloroacetic acid.

Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue.

Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T.