Hui Li

Publications (3)5.03 Total impact

• Article: 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.

  Hui Li, Michelle L Smith, O Alberto Chiesa, Philip J Kijak
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  ABSTRACT: 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.). The lower limit of quantitation (LLOQ) for both analytes in these matrices was validated at 2, 100, and 5 ng/mL in plasma, urine, and oral fluid respectively, and 10 ng/g in both kidney (cortex) and liver. The overall accuracy (average of 4 levels) is, for plasma, 104% (SDM) and 95% (AcSDM), with standard deviation of 9% (SDM) and 15% (AcSDM); for urine, 100% (SDM) and 106% (AcSDM), with standard deviation of 5% (SDM) and 6% (AcSDM); for oral fluid, 103% (SDM) and 103% (AcSDM), with standard deviation of 4% (SDM) and 4% (AcSDM); for kidney, 101% (SDM) and 111% (AcSDM), with standard deviation of 7% (SDM) and 6% (AcSDM); and for liver, 99% (SDM) and 115% (AcSDM), with standard deviation of 11% (SDM) and 9% (AcSDM). C18 SPE cartridges were used to clean-up these matrices, except for urine which was diluted directly with buffer before analysis by LC/MS/MS.
  Journal of Chromatography B 02/2009; 877(3):237-46. · 2.89 Impact Factor
• Article: Isobaric (gasless) laparoscopic liver and kidney biopsy in standing steers.

  O Alberto Chiesa, Jurgen von Bredow, Hui Li, Michelle Smith
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  ABSTRACT: The purpose of the current study was to investigate the suitability of an isobaric laparoscopic procedure, using a single port, for obtaining serial kidney and liver biopsy samples from standing steers. The samples were used in support of a pharmacokinetic tissue-fluid correlation study. Laparoscopic access was performed 3 times in each of 8 healthy Holstein steers, alternating from the right side to the left side and then to the right side again. The surgery was performed in standing stocks after the animals were given 3 doses of sulfadimethoxine sulfate intravenously and fasted for at least 18 h. Sedation and analgesia were achieved with acepromazine and xylazine. Lidocaine 2% was injected at the center of the paralumbar fossa (left or right), and an incision was made for introduction of a trocar-cannula assembly. Room air was allowed to enter the abdomen through the cannula at the time of insertion. Once the peritoneal cavity was reached, an operating endoscope was inserted. No pressurized insufflation was performed. A biopsy forceps was introduced into the operating channel of the endoscope to obtain a 100-mg kidney or liver sample. No complications were encountered. The 24 laparoscopic procedures provided 24 kidney and 16 liver samples. The results suggest that the isobaric (gasless) single-port laparoscopic technique is feasible for kidney and liver biopsy on standing steers. The procedure can be performed in a reliable and efficient manner in the sedated standing bovine.
  Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire 02/2009; 73(1):42-8. · 0.94 Impact Factor
• Article: Development of a quantitative multiclass/multiresidue method for 21 veterinary drugs in shrimp.

  Hui Li, Philip J Kijak
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  ABSTRACT: 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. The combined supernatant was further diluted with an aqueous internal standard solution, and 50 microL extract was injected into the HPLC instrument. An online SPE system was set up for automated sample cleanup. A triple quadrupole mass spectrometer equipped with an electrospray ionization source was operated in the multiple-reaction-monitoring mode to acquire data. The method has been validated at three levels within the designated linear ranges for each drug, with accuracies between 77 and 115%, and most CV values below 15%.
  Journal of AOAC International 94(2):394-406. · 1.20 Impact Factor