2.5.5 Stability
The QCs at multiple concentrations were stored in different condition including room temperature for 2 h, 4°C for 12 h, and -80°C for 60 days were analyzed to evaluate the stability. Freeze-thaw stability of samples\(\ \)was determined by conducting three freeze-thaw circles at low, medium and high concentrations in triplicate. The auto-sampler stability was assessed by reinjection of same sample after 90 min storage in the auto-sampler.