Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2017
Publication Date: 10/23/2017
Citation: Lehotay, S.J., Lightfield, A.R. 2018. Simultaneous analysis of aminoglycosides with many other classes of drug residues in bovine tissues by ultra high-performance liquid chromatography-tandem mass spectrometry using an ion-pairing reagent added to final extracts. Analytical and Bioanalytical Chemistry. 410:195-1109.
Interpretive Summary: Analysis of veterinary drug residues in food animal tissues is an important application for improved food safety and addressing antimicrobial resistance. Monitoring is routinely conducted in laboratories worldwide, but the expense of sophisticated instruments is very high and adds to the cost of the food products. In this study, novel conditions were devised and evaluated that allows the combination of two extracts from different sample preparation methods to use the same instrument for analysis rather than two instruments needed previously. Results showed that the new conditions met acceptable validation performance criteria for nearly 150 of the 174 veterinary drugs tested for possible implementation in the US National Residue Program, which would save costs by reducing expensive instrumentation needs.
Technical Abstract: The way to maximize scope of analysis, sample throughput, and laboratory efficiency in the monitoring of veterinary drug residues in food animals is to determine as many analytes as possible as fast as possible in as few methods as possible. Capital and overhead expenses are also reduced by using fewer instruments in the overall monitoring scheme. Traditionally, the highly polar aminoglycoside antibiotics require different chromatographic conditions from other classes of drugs, but in this work, we demonstrate that an ion-pairing reagent (sodium 1-heptanesulfonate) added to the combined final extracts from two sample preparation methods attains good separation of 174 targeted drugs, including 9 aminoglycosides, in the same 10.5 min ultrahigh-performance liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS) analysis. The full method was validated in bovine kidney, liver, and muscle tissues according to US regulatory protocols, and 137-146 (79-84%) of the drugs gave between 70-120% average recoveries with less than or equal to 25% RSDs in the different types of tissues spiked at 0.5, 1, and 2 times the regulatory levels of interest (10-1000 ng/g depending on the drug). This method increases sample throughput and the possible number of drugs monitored in the US National Residue Program, and requires only one UHPLC-MS/MS method and instrument for analysis rather than two by the previous scheme.