Nominal conc. Mean peak area of standard (× 104) (n=6)  Extraction recovery Matrix effect (ng/ml) neat spiked in serum extract spiked in serum   Mean (%) CV (%) 3 1.26 1.20 1.23 102.77 1.09 94.90 75 27.66 28.09 29.10 103.58 1.40 101.57 150 48.16 51.68 53.39 103.34 2.16 107.31

Table 2 : Matrix effect and extraction recovery of ertapenem in serum at low, mid and high QC concentrations.