Application Note: Automated Extraction-SPE-LC-MS of Antibiotics in Egg

Automated extraction, SPE clean-up and LC-MS/MS determination of 5 antibiotics in egg results in excellent matrix elimination, accuracy and precision.

A liquid autosampler and sample preparation workstation performs the highly efficient mixing, required for liquid extraction of complex matrices such as chicken egg, combined with SPE clean-up using standard dimension SPE cartridges and introduction of the clean extract to the LC-MS/MS system (Agilent Ultivo Triple Quadrupole Mass Spectrometer). Determination of 5 antibiotics in egg was performed using a deuterated antibiotic as internal standard. The method was readily automated using the GERSTEL MPS roboticPRO sampler. Evaluation of the method showed the egg extracts to be well mixed within 2.5 min using the GERSTEL QuickMix Option. Linear calibration curves resulting in R2 values 0.99 or greater were achieved for the analyzed compounds. The overall LLE-SPE-LC-MS/MS method proved to be accurate and precise. Accuracy data averaged 102 % (range: 94.6 % – 115 %) and precision data averaged 3.92 % RSD (range: 1.23 % -11.2 %) for the analysed antibiotics.