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Comparison of Lateral Flow Assay, Kidney Inhibition Swab, and Liquid Chromatography–Tandem Mass Spectrometry for the Detection of Penicillin G Residues in Sow Urine

Shelver Weilin L., Chakrabarty Shubhashis, Smith David J.
Journal of agricultural and food chemistry 2017 v.65 no.8 pp. 1778-1783
benzylpenicillin, kidneys, liquid chromatography, slaughter, sows, storage time, tandem mass spectrometry, urine
Sows (n = 126) were administered penicillin G; urine, collected at slaughter, was screened by kidney inhibition swab (KIS; 4 h testing time) and then stored at −80 °C (∼1200 days) until analysis by lateral flow assay (LF, ∼5 min testing time) and tandem quadrupole LC-MS/MS (TQ) analysis. The stability of penicillin in urine during storage was verified using TQ analyses. Quantitative results were well-correlated (R² = 0.98) with only a ∼10% decrease in penicillin concentration during the 3-year storage period. KIS retesting of stored samples returned results consistent with the original analyses. Lateral flow assay results were highly correlated with the KIS and TQ results. A KIS positive sample, which was not confirmed by TQ or LF, was assayed by Triple-TOF LC-MS to determine the cause of the apparent false positive. This study suggests LF can be used to quickly and efficiently screen for penicillin G residues before slaughter.