Quantification and confirmation of flunixin in equine plasma by liquid chromatography–quadrupole time-of-flight tandem mass spectrometry

Luo, Yang; Rudy, Jeffrey A.; Uboh, Cornelius E.; Soma, Lawrence R.; Guan, Fuyu; Enright, James M.; Tsang, Deborah S.

doi:10.1016/j.jchromb.2003.11.002

Cited by 29 publications

(17 citation statements)

References 13 publications

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“…We demonstrated previously the use of laboratory quality control samples (LQCS) as a simple, fast and acceptable method for estimating measurement uncertainty 17. In this study, measurement uncertainty was estimated from 18 LQCS data 18–20.…”

Section: Resultsmentioning

confidence: 99%

Biomarkers of alcohol abuse in racehorses by liquid chromatography/tandem mass spectrometry

You

Uboh

Soma

et al. 2007

Rapid Comm Mass Spectrometry

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A rapid and sensitive method was developed for the screening, quantification and confirmation of ethyl glucuronide (EG) and ethyl sulfate (ES) as biomarkers for alcohol administration to racehorses using liquid chromatography coupled on-line with triple quadrupole tandem mass spectrometry. Urine sample aliquots (0.1 mL) were pre-treated by protein precipitation. Separation of EG and ES was achieved on an Ultra PFP column. Isocratic elution with a flush step was performed using 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B). Analysis was performed by negative electrospray ionization in multiple reaction monitoring mode. The retention times for EG and ES were 1.7 +/- 0.30 and 3.4 +/- 0.30 min, respectively. The internal standard used was d(5)-ethyl glucuronide with a retention time of 1.7 +/- 0.30 min. The entire separation was completed in <5 min. The limit of detection (LOD) and of quantification (LOQ) for both analytes were 100 ng/mL (S/N > or =3) and 500 ng/mL, respectively. The limit of confirmations (LOC) for EG and ES were 500 ng/mL and 1.0 microg/mL, respectively. The assay was linear over a concentration range of 0.5-100 microg/mL (r(2) > 0.995). Intra- and inter-day accuracy and precision were less than 15%. The analytes were stable in urine for 24 h at room temperature, 10 days at 4 degrees C and 21 days at -20 degrees C and -70 degrees C. Ion suppression or enhancement due to matrix effect was negligible. The measurement uncertainty was <14% for EG and <25% for ES. This method was successfully used for the quantification of EG and ES in urine samples following alcohol administration to research horses and for screening and confirmation of EG and ES in urine samples obtained from racehorses post-competition. The method is simple, rapid, inexpensive, and reliably reproducible.

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Section: Resultsmentioning

confidence: 99%

Biomarkers of alcohol abuse in racehorses by liquid chromatography/tandem mass spectrometry

You

Uboh

Soma

et al. 2007

Rapid Comm Mass Spectrometry

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“…Measurement uncertainty can be estimated using laboratory quality control samples (LQCS) as previously demonstrated (51,52). In this study, MU was estimated using 33 LQCS.…”

Section: Estimation Of Measurement Uncertaintymentioning

confidence: 99%

Analysis of Gabapentin in Equine Plasma with Measurement Uncertainty Estimation by Liquid Chromatography-Tandem Mass Spectrometry

Liu

Uboh

Soma

et al. 2011

Journal of Analytical Toxicology

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Gabapentin (GPT) is an antiepileptic drug that was approved in 1993 for use in the management of neurotrophic pain and as an adjunctive therapy for refractory partial seizure in humans.It is also being tested in veterinary medicine as an adjunctive medication in the treatment of pain due to laminitis, neuropathic, or chronic pain. Gabapentin is readily available by prescription and even on the internet; therefore, it has the potential of being used in racehorses to mask pain. It is for this reason that a sensitive liquid chromatography-tandem mass spectrometry method has now been developed for the analysis of GPT in equine plasma and for studying the pharmacokinetic and pharmacodynamic profiles of GPT in the horse. Sample preparation was by rapid protein precipitation with acetonitrile. Analyte separation was achieved on a reversed-phase ACE C 18 column and analyzed by a hybrid triple-quadrupole linear ion trap mass spectrometer in positive electrospray ionization mode. Limits of detection, quantification, and confirmation of GPT were 1, 10, and 20 ng/mL, respectively. Calibration curve showed excellent linearity within the 10-2500 ng/mL range (r 2 > 0.999). Intra-and interday precision defined by coefficient of variation was <10%. Intra-and interday accuracy (bias %) was within 90-110%. Measurement uncertainty estimation was 8.6%. The method has been successfully used in the analysis of GPT in equine plasma following its administration to research horses for pharmacokinetic studies and in routine forensic analysis for doping control in racehorses in the State of Pennsylvania.

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“…Literature data for analysis of NSAIDs indicate extraction and cleanup procedures for the determination of one or two compounds,3, 7–20 with mass spectrometry as the main detection technique. No literature data were found on multi‐residue methods in bovine muscle for structurally different compounds.…”

Section: Maximum Residue Limits (Mrls) Set For Nsaids In Bovine Musclementioning

confidence: 99%

Multi‐residue liquid chromatography/tandem mass spectrometry method for the detection of non‐steroidal anti‐inflammatory drugs in bovine muscle: optimisation of ion trap parameters

Hoof

Wasch

Poelmans

et al. 2004

Rapid Comm Mass Spectrometry

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A multi-residue liquid chromatography/tandem mass spectrometry method (LC/MS2) was developed for the detection of the non-steroidal anti-inflammatory drugs acetylsalicylic acid (via the marker residue salicylic acid), flunixin, phenylbutazone, tolfenamic acid, meloxicam and ketoprofen, in bovine muscle. After extraction of the bovine muscle with acetonitrile, the cleanup was performed using a Oasis HLB column. The evaporated eluate was reconstituted and analysed by LC/MS2. To obtain optimal detection of salicylic acid and phenylbutazone, the ion trap mass spectrometric parameters activation q and maximum ion injection time, respectively, were optimised. The activation q for salicylic acid was increased to obtain reliable detection of both salicylic acid and its product ion. The maximum ion injection time for the time segment containing phenylbutazone was decreased since there were not enough scans across the chromatographic peak of this compound. The multi-residue method was able to detect the different analytes below or at the maximum residue limit (MRL) or minimum required performance limit (MRPL) or, in the case of phenylbutazone and ketoprofen, at 100 and 20 microg kg(-1), respectively.

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Quantification and confirmation of flunixin in equine plasma by liquid chromatography–quadrupole time-of-flight tandem mass spectrometry

Cited by 29 publications

References 13 publications

Biomarkers of alcohol abuse in racehorses by liquid chromatography/tandem mass spectrometry

Biomarkers of alcohol abuse in racehorses by liquid chromatography/tandem mass spectrometry

Analysis of Gabapentin in Equine Plasma with Measurement Uncertainty Estimation by Liquid Chromatography-Tandem Mass Spectrometry

Multi‐residue liquid chromatography/tandem mass spectrometry method for the detection of non‐steroidal anti‐inflammatory drugs in bovine muscle: optimisation of ion trap parameters

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