Stability procedures were employed to evaluate the stability of the analytes during sample collection and handling after long- term and short-term storage. The spiked samples containing TCs and QNs were prepared and stored in a clear plastic container at ambient temperature, 4 °C and _20 °C and then analyzed by the present method. TCs and QNs in the milk samples were found to be stable for one week, when stored at 4 °C or 2 weeks at _20 °C. Extracted samples were found to be stable for at least 3 days at 4 °C and for 1 week, when stored at _20 °C, according to the degradation criterion of _15% [26]. The studied antibiotics in the meat samples were found to be stable for 4 days when stored at 4 °C, or one week when stored at _20 °C.