Do Hui Kim (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Mi-Young Park (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Do Hui Kim (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Chung-Oui Hong (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Se-Hyung Kim (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Jisu Nam (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Sunjin Park (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Seon-Young Lee (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Hyun-Ok Ku (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Mi-Young Park (Veterinary Drugs & Biologics Division, Animal and Plant Quarantine Agency (APQA))

Phenylbutazone (PBZ) is a non-steroidal anti-inflammatory drug (NSAID) used in veterinary medicine to manage pain and fever. However, it can cause adverse effects such as blood dyscrasias and gastrointestinal ulceration. Since humans may be exposed to PBZ residues through the consumption of chicken muscle, South Korea has established a Maximum Residue Limit (MRL) for PBZ as “not detected”. Therefore, in this study, a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine PBZ residues in chicken muscle following CODEX Guidelines (CAC/GL 71-2009). The sample pretreatment method involves extraction steps using a mixture of acetonitrile and dichloromethane, followed by purification steps using MgSO₄, PSA, and C₁₈. PBZ was separated using a C18 column under the gradient condition with ammonium acetate solution and acetonitrile with electrospray ionization (ESI) in positive ion mode. The developed method demonstrated good linearity in the concentration range of 2–70 ng/mL, with a coefficient of determination (R2) of 0.9998. The limit of detection (LOD) and limit of quantitation (LOQ) were determined to be 1 and 5 ng/mL, respectively. Accuracy and precision were evaluated at 5, 10, and 25 ng/mL, yielding recoveries of 98.1–109.2% with coefficient of variation (CV) values of less than 8.5%. The method met validation criteria and is considered suitable for application in the exploratory surveillance study.