UHPLC–MS/MS method for the quantitation of penicillin G and metabolites in citrus fruit using internal standards

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 1044-1045; pp. 87 - 94
• Main Authors: Canzani, Daniele, Hsieh, Kevin, Standland, Matthew, Hammack, Walter, Aldeek, Fadi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.02.2017
• Subjects: Chromatography, High Pressure Liquid - methods; Chromatography, High Pressure Liquid - standards; Citrus - chemistry; Fruit - chemistry; Huanglongbing (HLB); Internal standards; LC–MS/MS; Limit of Detection; Linear Models; Metabolites; Method development; Penicillin G; Penicillin G - analysis; Penicillin G - chemistry; Penicillin G - metabolism; Reference Standards; Reproducibility of Results; Tandem Mass Spectrometry - methods; Tandem Mass Spectrometry - standards; Huanglongbing (HLB); Internal standards; Metabolites; Method development; Penicillin G; LC–MS/MS
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2017.01.012

•Development and validation of LC–MS/MS method to identify and quantitate penicillin G and two of its metabolites, penillic acid and penilloic acid, in citrus fruit.•Improvement of a previous method by incorporating isotopically labeled internal standards, namely, penillic acid-D5, and penilloic acid-D5.•Method enhancement and precision of measurements. Penicillin G has been applied to citrus trees as a potential treatment in the fight against Huanglongbing (HLB). Here, we have developed and validated a method to identify and quantitate penicillin G and two of its metabolites, penillic acid and penilloic acid, in citrus fruit using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS). This method improves upon a previous method by incorporating isotopically labeled internal standards, namely, penillic acid-D5, and penilloic acid-D5. These standards greatly enhanced the accuracy and precision of our measurements by compensating for recovery losses, degradation, and matrix effects. When 2g of citrus fruit sample is extracted, the limits of detection (LOD) were determined to be 0.1ng/g for penicillin G and penilloic acid, and 0.25ng/g for penillic acid. At fortification levels of 0.1, 0.25, 1, and 10ng/g, absolute recoveries for penillic and penilloic acids were generally between 50–70%. Recoveries corrected with the isotopically labeled standards were approximately 90–110%. This method will be useful for the identification and quantitation of drug residues and their degradation products using isotopically labeled standards and UHPLC–MS/MS.