A acceptor,final is the peak area of an analyte obtained by LC-MS analysis of the acceptor solution after extraction. A postspiked blank matrix is the peak area obtained from blank matrix sample spiked after extraction to the same level as the pre-extraction spiked sample. In this way, recoveries were corrected for potential matrix effects during LC-MS analysis. Sample and acceptor volumes were equal and therefore not corrected for. The calculates was performed in this manner since the sample concentration (100 ng mL -1 ) was within the linear range of the UHPLC-MS method for all model analytes.